Intel Profile for Remote Attestation

Internet-Draft	Intel profile	March 2025
Beaney, et al.	Expires 27 September 2025	[Page]

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1. Introduction

This profile describes extensions and restrictions placed on Reference Values, Endorsements, and Evidence that support attestation capabilities of Intel products containing Intel(R) SGX(TM) or Intel(R) TDX(TM) technology, or Intel(R) products that contain DICE [DICE.engine] root of trust, DICE layers [DICE.layer], or modules that implement SPDM [DMTF.SPDM].¶

The CoRIM specifications [DICE.CoRIM] and [I-D.ietf-rats-corim] define a baseline schema for Reference Values and Endorsements that form the foundation for the extensions defined in this profile. [I-D.ietf-rats-corim] contains a foundational representation for Attester actual state that Evidence, as specified by [DICE.Attest], [TCG.CE], and [DMTF.SPDM], Reference Values, and Endorsements can map to that helps ensure compatibility with a broad spectrum of Verifier implementations. The Reference Values extensions in this profile describe reference state that can be expressed as set membership or value ranges. This profile defines extensions to CoRIM that support appraisal matching that is based on set membership, masked values, and numeric ranges.¶

The baseline CoRIM, as defined by [DICE.CoRIM] is a subset of the Intel profile. Intel products that implement exclusively to the baseline CoRIM may not rely upon this profile. The Intel profile extensions may be generally useful. Implementations based on the Intel profile does not necessarily imply an implementation is an Intel product.¶

This profile extends CoMID measurement-values-map, as defined by [DICE.CoRIM] (see also [I-D.ietf-rats-corim]), with measurement types that are unique to Intel products. Some measurement types are specific to Reference Values where multiple reference states may be included in reference manifests. Intel profile extensions use a CBOR tagged value that defines a comparison operator and operands that instruct Verifiers regarding subset, range, and masked values matching semantics. For example, a numeric operator 'greater-than' instructs the Verifier to match a numeric Evidence value if it is greater than a numeric range operand.¶

This profile follows the Verifier behavior defined by [DICE.CoRIM] and extends Verifier behavior to include operator-operand matching. If no operator is specified by Reference Values statements, the Verifier defaults to baseline [DICE.CoRIM] matching semantics. If Evidence matches Reference Values and Endorsements apply, Endorsed Values may be added to the accetped claims set. When all Evidence and Endorsements are processed, the Verifier's set of accepted claims is available for Attestation Results computations. This profile doesn't define Attestation Results. Rather, an Attestation Results profile, such as [I-D.kdyxy-rats-tdx-eat-profile] may be referenced instead.¶

This profile is compatible with multiple Evidence formats, as defined by [DICE.Attest], [TCG.CE], and [DMTF.SPDM]. It describes considerations when mapping Evidence formats to CoRIM [DICE.CoRIM] that a Verifier may use when performig appraisals.¶

2. Conventions and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

The reader is assumed to be familiar with the terms defined in Section 4 of [RFC9334] and [I-D.ietf-rats-endorsements].¶

3. Background

Complex platforms may contain a variety of hardware components, several of which may contain a hardware root of trust. Each root of trust may anchor one or more layers [DICE.layer] resulting in multiple instances of attestation Evidence. Evidence may be integrity protected by digital signatures, such as certificates [DICE.Attest], tokens [RFC8392] or by a secure transport [DMTF.SPDM]. For example, a system bus may allow dynamically configured peripheral devices that have attestation capabilities. Confidential computing environments, such as SGX, may extend an initial boundary to include a peripheral, or a peer enclave, that together forms a network of trustworthy nodes that a remote attestation Verifier may need to appraise. Multiple Evidence blocks may be combined into a composite Evidence block [I-D.ietf-rats-msg-wrap] that is more easily conveyed. Complex platforms may have one or more lead Attester endpoints that communicate with a remote Verifier to convey composite Evidence. The composition of the complex platform is partially represented in the composite Evidence.¶

However, composite Evidence may not fully describe platform composition. A complex platform may consist of multiple subsystems, such as network adapters, storage controllers, memory controllers, special purpose processors, etc. The various sub-subsystem components vendors may create hardware bills of material (HBOM) that describe sub-system composition. A complex platform vendor may assemble various sub-system components whose composition is described by a platform HBOM. Although CoRIM may be used to create HBOMs, use of this profile for HBOM creation is unanticipated.¶

Nevertheless, a complex system may contain multiple identical instances of sub-sytem components that produce identical Evidence blocks. Additionally, dynamic insertion or removal of a component may result in composite Evidence blocks that reflect this dynamism.¶

4. Profile Identifier

This profile applies to Reference Values from a CoRIM manifest that a Verifier uses to process Evidence.¶

Profile identifier structures are defined by CoRIM [I-D.ietf-rats-corim], EAT [I-D.ietf-rats-eat] and Concise Evidence [TCG.CE].¶

4.1. Intel Profile

The profile identifier for the Intel Profile is the OID:¶

{joint-iso-itu-t(2) country(16) us(840) organization(1) intel(113741) (1) intel-comid(16) profile(1)}¶

2.16.840.1.113741.1.16.1¶

4.2. Profile Specific Media and Content Types

This profile uses the following media types:¶

"application/eat+cwt"¶
"application/eat+cwt; eat_profile=2.16.840.1.113741.1.16.1"¶
"application/rim+cbor" (TBA)¶
"application/rim+cbor" (TBA); profile=2.16.840.1.113741.1.16.1"¶

This profile uses the following content formats:¶

Table 1
Content Type	C-F ID	TN Function
"application/eat+cwt"	263	1668547081
"application/eat+cwt; eat_profile=2.16.840.1.113741.1.16.1"	10005	1668556861
"application/toc+cbor"	10570	1668557428
"application/ce+cbor"	10571	1668557429

This profile uses the following top level CBOR tags (not already listed):¶

501, 570, 571¶

5. Attester Anatomy

Attesters implement DICE layering using an initial Attesting Environment, also called a Root of Trust (RoT), that collection claims about one or more Target Environments. A Target Environment may become an Attesting Environment for a subsequent Target Environment, and so forth. There may be more than one RoT in the same Attester.¶

Attesting Environments generate Evidence by signing collected claims using an Attestation Key. Environments may have other keys besides attestation keys. Keys can be regarded as claims that are collected and reported as Evidence. Keys can also be regarded as Target Environments that have measurements that are specific to the key.¶

Confidential computing environments are Target Environments that can dynamically request Evidence from an Attesting Environment agent. Such Evidence may also be referred to as a 'Quote'.¶

Each DICE layer may produce signed Evidence. Evidence formats include both signature and measurements formats. Signature formats may include a mix of X.509 certificates and EAT CWTs. Evidence measurements formats may include a mix of ASN.1 and CBOR, where ASN.1 uses DiceTcbInfo and related varients and CBOR uses concise evidence, and CMW. Multiple Evidence blocks may be bundled using CMW collections.¶

Target Environments (other than cryptographic keys) are primarily identified using OIDs from Intel's OID arc (2.16.840.1.113741). Keys are identified using key identifiers, public key, or certificate digests as defined by $crypto-key-type-choice [I-D.ietf-rats-corim].¶

6. Evidence Profile

Evidence may be integrity protected in various ways including: certificates [RFC5280], SPDM transcript [DMTF.SPDM], and CBOR web token (CWT) [RFC8392]. Evidence contained in a certificate may be encoded using DiceTcbInfo and DiceTcbInfoSeq [DICE.Attest]. Evidence contained in an SPDM payload may be encoded using the SPDM Measurement Block [DMTF.SPDM]. Evidence may be formatted as concise-evidence [TCG.CE] and included in an alias certificate or an SPDM Measurement Manifest.¶

The DiceTcbInfo and SPDM Evidence formats can be translated to CoMID. The concise evidence format is native to CoMID. This profile documents evidence mapping from DiceTcbInfo and SPDM Measurement Block to CoMID, as defined by [DICE.CoRIM].¶

The CoMID extensions defined by this profile Section 8.2 are applied to concise-evidence so that Verifiers that support this profile can consistently apply a common schema across Evidence, Reference Values, and Endorsements.¶

6.1. Evidence Hierarchy

Evidence hierarchy refers to DICE layering where the platform bootstrap components double as Attesting Environments that collect measurements of the other bootstrap components (as Target Environments) until the quoting agent (e.g., SGX Quoting Enclave (QE), TDX Quoting TD (QTD)) is initialized. Tenant trusted execution environment (TEE) components can be dynamically loaded then request Evidence from its quoting agent. Quoting agents locally verify then sign measurments using the QTD / QE attestation key. A hierarchy of Evidence consisting of all the Evidence from a RoT to the tenant environment describes the Attester.¶

A complex device may have multiple roots of trust, such as [DICE.engine], each contributing an evidence hierarchy that results in several Evidence "chains", that together, constitute a complete Evidence hierarchy for the Attester device.¶

The Evidence hierarchy should form a spanning tree that contains all Attester Evidence. All Attesting Environments within the device produce the spanning tree. CoRIM manifests contain Reference Values for the spanning tree so that Verifiers do not assume the spanning tree is defined by Evidence. Note that a failure or comporomise within the Attester device could result in a portion of the spanning tree being omitted.¶

Evidence examples:¶

A DICE certificate chain with a DiceTcbInfo extension, a DiceTcbInfoSeq extension, and a ConceptualMessageWrapper (CMW) [I-D.ietf-rats-msg-wrap] extension containing a CBOR-encoded tagged-concise-evidence.¶
An SPDM alias intermediate certification chain containing a CMW extension, and an SPDM measurement manifest containing tagged-concise-evidence.¶

6.2. Concise Evidence

Concise evidence is a CDDL representation of Evidence [TCG.CE] that uses expressions from CoMID, which are a subset of CoRIM. See [DICE.CoRIM] and [I-D.ietf-rats-corim]. Evidence describes the actual state of the Attester. tagged-concise-evidence uses a CBOR tag (571) to identify concise-evidence [TCG.CE]. This profile uses concise-evicence in conceptual message wrappers [I-D.ietf-rats-msg-wrap] and EAT tokens [I-D.ietf-rats-eat] to encode Evidence. This profile extends concise-evidence by extending measurement-values-map.¶

7. Reference Values and Endorsements Profile

The CoRIM specifications [DICE.CoRIM] and [I-D.ietf-rats-corim] define a baseline schema for Reference Values and Endorsements in this profile. The profile defines extensions to CoRIM for measurement types that are not representable by CoRIM or are more conveniently represented. This profile doesn't require use of extensions when base capabilities will suffice.¶

7.1. Concise Module ID Tag (CoMID)

This profile uses concise-mid-tag in conceptual message wrappers [I-D.ietf-rats-msg-wrap] and CoRIMs. This profile extends concise-mid-tag by extending measurement-values-map. Several extensions define two forms, one for representing actual state which is used for Endorsements and Evidence. The other form is used to represent reference state which is used for Reference Values.¶

7.2. Raw Value Measurements

Raw value measurements encode vendor-defined values opaquely. However, the mkey value can add vendor-specific semantics when used with raw-value and name measurement types. Additionally, specific environment-map values can supply vendor-specific semantics to raw-value and name measurement types.¶

Environments that project vendor-specific semantics are as follows:¶

Table 2
Envoronment Identifier	Value	Semantics
class-id:OID=2.16.840.1.113741.1.5.3.6.8	560(bytes)	device type

8. CoRIM Extensions

The Intel Profile extends measurement-values-map which is used by Evidence, Reference Values, and Endorsed Values by defining code points from the negative integer range.¶

Reference Values extensions define types that can have multiple Reference Values that "match" a singleton Evidence value called "non-exact match" matching. Reference state expressions define non-exact-match matching semantics in terms of numeric ranges, date-time ranges, sets, and masks. Reference Values data types are identified by the CBOR tag #6.60010(...).¶

8.1. Expressions

Expressions are used to specify richer Reference Values measurements that expect non-exact matching semantics. The Reference Value expression instructs the Verifier regarding matching parameters, such as greater-than or less-than, ranges, sets, etc. Typically, the Evidence value is one operand of an expression and the Reference Value contains the operator and additional operands.¶

The operator and remaining operands are contained in an array. Expression arrays have an operator followed by zero or more operands. The operator definition identifies the additional operands and their data types. A Verifier forms an expression using Evidence as the first operand, obtains the operator from the first entry in the expression array, and any remaining array entries are operands.¶

This document describes operations using infix notation where the first operand, operand_1, is obtained from Evidence, followed by the operator, followed by any remaining operands: operand_2, operand_3, etc...¶

For example:¶

From Evidence: operand_1, from Reference Values: [ operator, operand_2, operand_3, ... ].¶

Expression records are CBOR tagged to indicate the following CBOR is to be evaluated as an expression. Expression statements found in Reference Values informs the Verifier that Evidence is needed to complete the expression equation. Appraisal processing MUST evaluate the expression.¶

This profile anticipates use of the CBOR tag #6.600XX to identify expression arrays. See Section 12.¶

For example:¶

#6.600XX([ operator, operand_2, operand_3, ... ]).¶

8.1.1. Expression Operators

There are several classes of operators as follows:¶

Numeric: The numeric operand can be an integer, unsigned integer, or floading point value.¶
Set: The set operand can be an set (array) of any primitive value or a set of arrays containing any primitive value. The position of the items in a set is unordered, while the position of items in an array within a set is ordered.¶
Date-Time: The date-time operators compare two date-time values, while the epoch operators determine if a date-time value is within a range defined by an epoch and a grece period relative to the epoch.¶
Mask: The mask operator compares two bit fields where a bit-field is compared to a second bit-field using a bit-field-mask that selects the bits to be compared. The bit-field may contain a sequence of bytes of any length. The bit-field-mask should be the same length as the bit-field.¶

8.1.1.1. Equivalence Operator

By default, exact match rules are assumed. Consequently, no operator artifact is needed when Evidence values are identical to Reference Values.¶

8.1.2. Numeric Expressions

Numeric operators apply to values that are integers, unsigned integers or floating point numbers. There are four numeric operators:¶

greater-than (gt),¶
greater-than-or-equal (ge),¶
less-than (lt),¶
less-than-or-equal (le).¶

The equals operator is not defined because an exact match rule is the default rule when an Evidence value is identical to a Reference Value.¶

The numeric operator data type definitions are as follows:¶

numeric-type = integer / unsigned / float
numeric-operators /= op.gt
numeric-operators /= op.ge
numeric-operators /= op.lt
numeric-operators /= op.le
numeric-expression = [ numeric-operators, numeric-type ]
tagged-numeric-expression = #6.60010(numeric-expression)

A numeric expression is an array containing a numeric operator and a numeric operand. The operand contains a numeric Reference Value that is matched with a numeric Evidence value.¶

Evidence and Reference Values MUST be the same numeric type. For example, if a Reference Value numeric type is integer, then the Evidence numeric value must also be integer.¶

This profile defines four macro numeric expressions, one for each numeric operator:¶

tagged-numeric-gt,¶
tagged-numeric-ge,¶
tagged-numeric-lt,¶
tagged-numeric-le.¶

In each case, the numeric operator is used to evaluate a Reference Value operand against an Evidence value operand that is obtained from Evidence.¶

If the expression is read using infix notation, the first operand is Evidence, followed by the operator, followed by the Reference Value operand.¶

Example:¶

<evidence_numeric> <le> <reference_numeric>¶

The numeric expression definitions are as follows:¶

tagged-numeric-gt = #6.60010( [
    op.gt .within numeric-operators,
    reference-value: numeric-type ] )
tagged-numeric-ge = #6.60010( [
    op.ge .within numeric-operators,
    reference-value: numeric-type ] )
tagged-numeric-lt = #6.60010( [
    op.lt .within numeric-operators,
    reference-value: numeric-type ] )
tagged-numeric-le = #6.60010( [
    op.le .within numeric-operators,
    reference-value: numeric-type ] )

8.1.3. Set Expressions

Set operators allow Reference Values, that are expressed as a set, to be compared with Evidence that is expressed as either a primitive value or a set.¶

Set expression statements have two forms:¶

A binary relation between a primitive object 'O' and a set 'S', and¶
A binary relation between two sets, an Evidence set 'S1' and a Reference Values set 'S2'.¶

The first form, relation between an object and a set, has two operators:¶

member and¶
not-member.¶

The Evidence object 'O' is evaluated with the Reference Values set 'S'.¶

The op.member and op.not-member operators expect a Reverence Value set as operand_2 and a primitive Evidence value as operand_1. Evaluation tests whether operand_1 is a member of the set operand_2.¶

Example:¶

<evidence-value> <set-operator> <reference-set>¶

The set data type definitions are defined as follows:¶

member = 6
not-member = 7
set-operators /= op.mem
set-operators /= op.nmem

set-digest-type /= [ * digest ]
set-digest-expression = [ set-operators, set-digest-type ]
tagged-set-digest-expression = #6.60020( set-digest-expression )

set-tstr-type /= [ * tstr ]
set-tstr-expression = [ set-operators, set-tstr-type ]
tagged-set-tstr-expression = #6.60021( set-tstr-expression )

A set expression array contins a set operator followed by a set of Reference Values. The set is defined by set-type.¶

The set expression type definitions are as follows:¶

tagged-exp-digest-member = #6.60020([
    op.mem .within set-operators, set-digest-type ])

tagged-exp-digest-not-member = #6.60020([
    op.nmem .within set-operators, set-digest-type ])

tagged-exp-tstr-member = #6.60021([
    op.mem .within set-operators, set-tstr-type ])

tagged-exp-tstr-not-member = #6.60021([
    op.nmem .within set-operators, set-tstr-type ])

Examples:¶

<evidence_object> <member> <reference_set>¶
<evidence_object> <not-member> <reference_set>¶

The Evidence object MUST NOT be nil.¶

The Reference Values set may be the empty set.¶

The second form, a relation between two sets, has three operators:¶

subset,¶
superset,¶
disjoint.¶

The fist set, S1 is Evidence and set, S2 is the Reference Values set.¶

The subset, superset, and disjoint operators test whether an Evidence set value satisfies a set operation, given a Reverence Value set.¶

Examples:¶

<evidence_set> <subset> <reference_set>¶
<evidence_set> <superset> <reference_set>¶
<evidence_set> <disjoint> <reference_set>¶

The Reference Values and Evidence sets may be the empty set.¶

The set of sets data type definitions are as follows:¶

; The CDDL here needs to be fixed, Ned to work on this
subset = 8
superset = 9
disjoint = 10
set-of-set-type = [ * [ + any ]]
set-of-set-operator = subset / superset / disjoint
set-of-set-expression = [ set-of-set-operator, set-of-set-type ]
tagged-set-of-set-expression = #6.60020(set-of-set-expression)

For subset, every member in the Evidence set 'S1', MUST map to a member in the Reference Values set 'S2'. The Evidence set, 'S1', MAY be a proper subset of 'S2'. For example, if every member in set 'S1' maps to every member in set 'S2' then matching is successful. A successful result produces the set 'S1'.¶

For superset, every member in the Reference Values set 'S2', MUST map to a member in the Evidence set 'S1'. A successful result produces the set 'S1'.¶

For disjoint, every member in the Evidence set 'S1' MUST NOT map to any member in the Reference Values set 'S2'. A successful result produces the empty set.¶

The set of sets expression definitions are as follows:¶

tagged-exp-subset = #6.60010([
    subset .within set-of-set-operator, set-of-set-type ])

tagged-exp-superset = #6.60010([
    superset .within set-of-set-operator, set-of-set-type ])

tagged-exp-disjoint = #6.60010([
    disjoint .within set-of-set-operator, set-of-set-type ])

8.1.4. Time Expressions

8.1.4.1. Date-Time Expressions

Date-time can be expressed in both string tdate or numeric time formats. There are four operators that are defined for date-time expressions:¶

lt determines if a date-time Evidence value is less than a Reference Values date-time.¶
le determines if a date-time Evidence value is less than or equal to a Reference Values date-time.¶
gt determines if a data-time Evidence value is greater than a Reference Values date-time.¶
ge determines if a data-time Evidence value is greater than or equal to a Reference Values date-time.¶

The date-time operators are in fact numeric. Expressions involving string date-time values must be converted to numeric format before the numeric comparison operator can be applied.¶

The numeric date-time data type definitions are as follows:¶

time-operators /= op.eq
time-operators /= op.gt
time-operators /= op.ge
time-operators /= op.lt
time-operators /= op.le
time-type = ~time
time-expression = [ time-operators, time-type ] ;#6.1(int or float)
tagged-time-expression = #6.60030( time-expression )

The string date-time data type definitions are as follows:¶

tdate-operators /= op.gt
tdate-operators /= op.ge
tdate-operators /= op.lt
tdate-operators /= op.le
tdate-type = ~tdate
tdate-expression = [ tdate-operators, tdate-type ] ;#6.0(string) - tdate converts to numeric
tagged-tdate-expression = #6.60031( tdate-expression )

The date-time expressions for evaluating time consist of a CBOR tagged record containing a time operator followed by a date-time value.¶

The gt expression compares a date-time value contained in Evidence to a Reference Values date-time. If the Evidence date-time value is greater-than to the Reference Value, then the Evidence value is accepted.¶

The ge expression compares a date-time value contained in Evidence to a Reference Values date-time. If the Evidence date-time value is greater-than-or-equal to the Reference Value, then the Evidence value is accepted.¶

The lt expression compares a date-time value contained in Evidence to a Reference Values date-time. If the Evidence date-time value is less-than to the Reference Value, then the Evidence value is accepted.¶

The le expression compares a date-time value contained in Evidence to a Reference Values date-time. If the Evidence date-time value is less-than-or-equal to the Reference Value, then the Evidence value is accepted.¶

In infix notation, a date-time value reported as Evidence in operand_1. The Reference Value expression contains a time comparison operator and operand_2 contains a reference date-time.¶

Example:¶

<evidence_date_time> <gt> <reference_date_time>¶

The numeric date-time expression definitions are as follows:¶

tagged-exp-time-eq = #6.60030([
    op.eq .within time-operators,
    time-type ])

tagged-exp-time-gt = #6.60030([
    op.gt .within time-operators,
    time-type ])

tagged-exp-time-ge = #6.60030([
    op.ge .within time-operators,
    time-type ])

tagged-exp-time-lt = #6.60030([
    op.lt .within time-operators,
    time-type ])

tagged-exp-time-le = #6.60030([
    op.le .within time-operators,
    time-type ])

The string date-time expression definitions are as follows:¶

tagged-exp-tdate-gt = #6.60031([
    op.gt .within tdate-operators,
    tdate-type ])

tagged-exp-tdate-ge = #6.60031([
    op.ge .within tdate-operators,
    tdate-type ])

tagged-exp-tdate-lt = #6.60031([
    op.lt .within tdate-operators,
    tdate-type ])

tagged-exp-tdate-le = #6.60031([
    op.le .within tdate-operators,
    tdate-type ])

8.1.4.2. Epoch Expressions

An epoch expression defines a timing window that can be used to determine recentness of a time stampped message. By default, the Verifier's current time implicitly defines an epoch. A grace period defines the epoch window differential, in seconds, that a timestamp must fall within to be valid.¶

Epochs don't have to rely on current time. [I-D.birkholz-rats-epoch-markers] defines several.¶

The epoch data type definitions are as follows:¶

epoch-operators /= op.eq
epoch-operators /= op.gt
epoch-operators /= op.ge
epoch-operators /= op.lt
epoch-operators /= op.le
epoch-seconds-type = ~time
$tagged-epoch-id /= tdate ; string - converted to ~time for comparisons
$tagged-epoch-id /= time ; int or float
$epoch-timestamp-type /= ~tdate
$epoch-timestamp-type /= ~time
epoch-expression = [
    epoch-operators,
    grace-period: epoch-seconds-type,
    ? epoch-id: $tagged-epoch-id
]
tagged-epoch-expression = #6.60032( epoch-expression )

An epoch expression array contains an epoch-operator followed by a grace period in seconds that is optionally followed by a $tagged-epoch-id. Epoch operators can be: gt, ge, lt, or le. The operator defines the position of the grace window relative to the epoch and epoch-grace-seconds defines the size of the window in seconds. If the default epoch type is not used, $tagged-epoch-id defines the alternate epoch scheme.¶

The $epoch-timestamp-type defines the timestamp type for the epoch scheme. By default, the timestamp is tdate.¶

The tagged-epoch-expression is an epoch-expression preceded by a CBOR tag for an expression array that has the value #6.60010.¶

The epoch expression definitions are as follows:¶

tagged-exp-epoch-gt = #6.60032([
    op.gt .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-ge = #6.60032([
    op.ge .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-lt = #6.60032([
    op.lt .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-le = #6.60032([
    op.le .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-id-gt = #6.60032([
    op.gt .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

tagged-exp-epoch-id-ge = #6.60032([
    op.ge .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

tagged-exp-epoch-id-lt = #6.60032([
    op.lt .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

tagged-exp-epoch-id-le = #6.60032([
    op.le .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

A variety of epoch expressions can be defined that convenently constrain epoch definition. The tagged-exp-epoch-gt expression defines an epoch window that is greater than the current date and time by the supplied grace period.¶

In infix notation, the timestamp value is within an epoch window that is defined by the current time, plus the grace period, and where the epoch-operator defines the shape of the epoch window.¶

Example epoch expression:¶

<evidence_timestamp> <epoch-operator> <grace_period> <current_time>¶

The Verifier adds grace_period to current_time to obtain the epoch window then applies the operator to determine if the evidence_timestamp is within the window.¶

8.1.5. Mask Expression

Reference Values expressed as an array of bits or bytes that uses a mask can indicate to a Verifier which bits or bytes of Evidence to ignore.¶

Reference Value and mask arrays MUST be the same length for the mask to be applied correctly. Normally, Evidence would not supply a mask, while Endorsed Values would. The mask-eq operator indicates that an Evidence value of type mask-type is compared with a Reference Value of type mask-type, and that a mask of type mask-type is applied to both values before comparing values. If the operator is mask-eq, then a binary equivalence comparison is applied.¶

The Verifier MUST ensure the lengths of values and mask are equivalent. If the mask is shorter than the values, the mask is padded with zeros (0) until it is the same length as the largest value. If the Evidence or Reference Value length is shorter than the mask, the value is padded with zeros (0) to the length of the mask.¶

The masked data type definitions are as follows:¶

mask-operators /= op.eq
mask-type = bstr
mask-expression = [ mask-operators, value: mask-type, mask: mask-type]
tagged-mask-expression = #6.60040( mask-expression )

If the Evidence bit field is a different length from the Reference Value and mask, the shorter length bit field is padded with zeros to accommodate the larger bit field.¶

The tagged-exp-mask-eq expression defines a tagged expression that applies the mask equivalence operator to an Evidence value and a Reference Value using the supplied mask.¶

In infix notation, the Evidence value is operand_1, followed by the mask operator, followed by a Reference Value, operand_2, followed by the mask, operand_3.¶

Example:¶

<evidence_value> <mask-eq> <reference_value> <mask>¶

If each bit in Evidence has a corresponding matching bit in the Reference Value, then the Evidence value is accepted.¶

The masked data expression definitions are as follows:¶

tagged-exp-mask-eq = #6.60040([ op.eq .within mask-operators, value: mask-type, mask: mask-type ] )

8.2. Measurement Extensions

This profile extends the CoMID measurement-values-map with additional code point definitions, that accommodate Intel SGX and similar architectures. Measurement extensions don't change Verifier behavior. An extension enables the Verifier to validate the profile compliance of the input evidence and reference values, as it defines the acceptable data types in evidence and the expression operator that is explicitly supplied with the Reference Values, see Section 8.1.1.¶

In cases where Evidence does not exactly match Reference Values, the operator definition determines the expected data types of the operands. Expected Verifier behavior is defined in Section 9 ¶

The measurement extensions that follow are assumed to be appraised according to the appriasal steps described in Section 8.1 of [I-D.ietf-rats-corim].¶

8.2.1. The tee-advisory-ids-type Measurement Extension

The tee.advisory-ids extension enables Attesters to report known security advisories and for Reference Values Providers (RVP) to assert updated security advisories. It can also be used by Endorsers to assert security advisory information through conditional endorsement.¶

The $tee-advisory-ids-type is used to specify a set of security advisories, where each identifier is represented using a string. Evidence may report a set of advisories the Attester believes are relevant. The set of advisories are constrained by the set-tstr-type structure.¶

As a Reference Value expression, an empty set can be used to signify that no outstanding advisories are expected. If the Evidence also contains the empty set then the Reference corroborates the Evidence.¶

The $tee-advisory-ids-type is a list of strings, each identifying a single security advisory. When used with Evidence the set-tstr-type type is used. When used with Reference Values or Endorsements the set-tstr-type, tagged-exp-tstr-member, or tagged-exp-tstr-not-member types can be used.¶

$$measurement-values-map-extension //= (
  &(tee.advisory-ids: -89) => $tee-advisory-ids-type
)
$tee-advisory-ids-type /= set-tstr-type
$tee-advisory-ids-type /= tagged-exp-tstr-not-member
$tee-advisory-ids-type /= tagged-exp-tstr-member

8.2.1.1. The tee-advisory-ids-type Comparison Algorithm

The comparison algorithm for tee-advisory-ids-type is used when Endorsement or Reference Values triples conditions are matched with an Environment Claims Tuple (ECT) in the Verifier's Accepted Claims Set (ACS). The triple condition containing a tee-advisory-ids-type Claim matches an ACS ECT according to the comparison algorithm for set of strings as defined in Section 9.2.¶

8.2.2. The tee-attributes-type Measurement Extension

The tee.attributes extension enables the Attester to report TEE attributes and an RVP to assert a reference TEE attributes and mask.¶

The $tee-attributes-type is used to specify TEE attributes in 8 or 16 byte words. If Evidence uses an 8 byte mask, then the Reference Values expression also uses an 8 byte value and mask.¶

The $tee-attributes-type is a singleton value omitting the mask value when used as Endorsement or Evidence and a tuple containing the reference and mask when used as a Reference Value.¶

$$measurement-values-map-extension //= (
  &(tee.attributes: -82) => $tee-attributes-type
)
$tee-attributes-type /= mask-type
$tee-attributes-type /= tagged-exp-mask-eq

Alternatively, the TEE attributes may be encoded using mkey where mkey contains the non-negative tee.attributes and mval.raw-value contains the $tee-attributes-type.mask-type value.¶

8.2.3. The tee-cryptokey-type Measurement Extension

The tee.cryptokeys extension identifies cryptographic keys associated with a Target Environment. If multiple $crypto-key-type-choice measurements are supplied, array position disambiguates each entry. Appraisal compares values indexed by array position.¶

$$measurement-values-map-extension //= (
  &(tee.cryptokeys: -91) => [ + $tee-cryptokey-type ]
)
$tee-cryptokey-type /= $crypto-key-type-choice

Alternatively, the TEE cryptokeys may be encoded using mkey where mkey contains the non-negative tee.cryptokeys and mval.cryptokeys contains the $tee-cryptokey-type value.¶

8.2.4. The tee-date-type Measurement Extension

The tee.tcbdate extension enables the Attester or Endorser to report the TEE date attribute and a RVP to assert a valid TEE matching operation.¶

The $tee-date-type is a date-time string when used for Evidence or Endorsement. When used for a Reference Value, either a tagged-tdate-expression or a tagged-epoch-expression describes the TCB validity.¶

$$measurement-values-map-extension //= (
  &(tee.tcbdate: -72) => $tee-date-type
)
$tee-date-type /= tdate-type
$tee-date-type /= tagged-exp-tdate-ge
;$tee-date-type /= tagged-exp-epoch-ge
;$tee-date-type /= tagged-exp-epoch-id-ge

tdate strings must be converted to numeric time before the tdate-operator, which is a numeric operator, can be applied.¶

Alternatively, the TEE tcbdate may be encoded using mkey where mkey contains the non-negative tee.tcbdate and mval.name contains the string representation $tee-date-type without the CBOR tag (i.e., ~tdate).¶

8.2.5. The tee-digest-type Measurement Extension

The tee.mrtee extension enables an Attester to report digests for the SGX enclave or TDX TD (e.g., MRENCLAVE, MRTD). The tee.mrsigner extension enables an Attester to report the signer of the TEE digest (e.g., MRSIGNER).¶

The $tee-digest-type has multiple type structures involving digest values. A singleton digest has a hash algorithm identifier and the digest value. When used as Evidence, either a signleton digest or a set of digests can be reported. When used as Reference Values or Endorsements, a set of digests can be asserted signifying equivalence matching. Alternatively, matching may be expressed as set membership or set difference expressions.¶

$$measurement-values-map-extension //= (
  &(tee.mrtee: -83) => $tee-digest-type
)
$$measurement-values-map-extension //= (
  &(tee.mrsigner: -84) => $tee-digest-type
)
$tee-digest-type /= digest ; see corim
$tee-digest-type /= digests-type ; see corim
$tee-digest-type /= set-digest-type
$tee-digest-type /= tagged-exp-digest-member
$tee-digest-type /= tagged-exp-digest-not-member

Alternatively, the TEE digests may be encoded using mkey where mkey contains the non-negative tee.mrtee or tee.mrsigner and mval.digests contains a digests-type value.¶

8.2.5.1. The tee-digest-type Comparison Algorithm

The comparison algorithm for tee-digest-type is used when the condition statement in an Endorsement or Reference Values triple is matched with an Environment Claim Tuple (ECT) from the Verifier's Accepted Claims Set (ACS). The comparison algorithm for set of digests is defined in Section 9.2.¶

8.2.6. The tee-epoch-type Measurement Extension

The tee.epoch extension enables the Attester to report an epoch Evidence measurement, and a RVP to assert an epoch Reference Value.¶

As Evidence, the $tee-epoch-type is a tdate timestamp.¶

As a Reference Value, the $tee-epoch-type is a grace period, in seconds, that is relative to the Verifier's current date and time, and an epoch operator: gt, ge, lt, or le. The Verifier evaluates whether the timestamp is within the grace period relative to the current date and time. The current date and time is implicit, and is assumed to be in tdate format.¶

The $tee-epoch-type is an $epoch-timestamp-type when used as Evidence or Endorsement and a $tagged-epoch-expression when used as a Reference Value.¶

$$measurement-values-map-extension //= (
  &(tee.epoch: -90) => $tee-epoch-type
)
$tee-epoch-type /= $epoch-timestamp-type
$tee-epoch-type /= tagged-exp-epoch-gt
$tee-epoch-type /= tagged-exp-epoch-ge
$tee-epoch-type /= tagged-exp-epoch-lt
$tee-epoch-type /= tagged-exp-epoch-le
$tee-epoch-type /= tagged-exp-epoch-id-gt
$tee-epoch-type /= tagged-exp-epoch-id-ge
$tee-epoch-type /= tagged-exp-epoch-id-lt
$tee-epoch-type /= tagged-exp-epoch-id-le

Alternatively, for Evidence, the TEE epoch timestamp may be encoded using mkey where mkey contains the non-negative tee.epoch and mval.name contains the string representation $tagged-epoch-id without the CBOR tag (i.e., ~tdate).¶

8.2.7. The tee-instance-id-type Measurement Extension

The tee.instance-id extension enables the Attester to report the TEE (TD or enclave) instance identifier as an Evidence value and the RVP to assert an exact-match Reference Value.¶

The $tee-instance-id-type is an unsigned integer or bstr.¶

$$measurement-values-map-extension //= (
  &(tee.instance-id: -77) => $tee-instance-id-type
)
$tee-instance-id-type /= uint
$tee-instance-id-type /= bstr

Alternatively, the TEE instance ID may be encoded using mkey where mkey contains the non-negative tee.instance-id and mval.raw-value contains the $tee-instance-id-type value. If the $tee-instance-id-type is an unsigned integer, the integer values is converted to a single byte bstr.¶

8.2.8. The tee-platform-instance-id-type Measurement Extension

Platform Instance ID is a globally unique identifier generated by the platform during Platform Establishment. This value remains consistent across trusted computing base (TCB) recoveries, but is regenerated during Platform Establishment due to desire to reset keys or to add and remove hardware. See (Section 3.7 [INTEL.DCAP]).¶

The tee.platform-instance-id extension enables the Attester to report the platform instance identifier as an Evidence value and the RVP to assert an exact-match Reference Value.¶

The $tee-platform-instance-id-type is a bstr.¶

$$measurement-values-map-extension //= (
  &(tee.platform-instance-id: -101) => $tee-platform-instance-id-type
)
$tee-platform-instance-id-type /= bstr

Alternatively, the platform instance ID may be encoded using mkey where mkey contains the non-negative tee.platform-instance-id and mval.raw-value contains the $tee-platform-instance-id-type value.¶

8.2.9. The tee-isvprodid-type Measurement Extension

The tee.isvprodid extension enables the Attester to report the ISV product identifier Evidence value and the RVP to assert an exact-match Reference Value.¶

The $tee-isvprodid-type is an unsigned integer.¶

The $tee-isvprodid-type is an exact match measurement.¶

$$measurement-values-map-extension //= (
  &(tee.isvprodid: -85) => $tee-isvprodid-type
)
$tee-isvprodid-type /= uint
$tee-isvprodid-type /= bstr

Alternatively, the TEE product ID may be encoded using mkey where mkey contains the non-negative tee.isvprodid and mval.raw-value contains the $tee-isvprodid-type value.¶

8.2.10. The tee-miscselect-type Measurement Extension

The tee.miscselect extension enables the Attester to report the (TBD:miscselect-description) Evidence value and the RVP to assert a Reference Value and mask.¶

The $tee-miscselect-type is a 4 byte value and mask.¶

The $tee-miscselect-type is a singleton mask-type value when used as Endorsement or Evidence and a tagged-mask-expression when used a Reference Value.¶

$$measurement-values-map-extension //= (
  &(tee.miscselect: -81) => $tee-miscselect-type
)
$tee-miscselect-type /= mask-type
$tee-miscselect-type /= tagged-exp-mask-eq

Alternatively, the TEE miscselect may be encoded using mkey where mkey contains the non-negative tee.miscselect and mval.raw-value contains the measurement value and mval.raw-value-mask` contains the mask value.¶

8.2.11. The tee-model-type Measurement Extension

The tee.model extension enables the Attester to report the TEE model string as Evidence and the RVP to assert an exact-match Reference Value.¶

The $tee-model-type is a string.¶

The $tee-model-type is an exact match measurement.¶

$$measurement-values-map-extension //= (
  &(tee.model: -71) => $tee-model-type
)
$tee-model-type /= tstr

Alternatively, the TEE model may be encoded using mkey where mkey contains the non-negative tee.model and mval.name contains the $tee-model-type value.¶

8.2.12. The tee-pceid-type Measurement Extension

The tee.pceid extension enables the Attester to report the PCEID as Evidence and the RVP to assert an exact-match Reference Value.¶

The $tee-pceid-type is a string.¶

The $tee-pceid-type is an exact match measurement.¶

$$measurement-values-map-extension //= (
  &(tee.pceid: -80) => $tee-pceid-type
)
$tee-pceid-type /= tstr

Alternatively, the PCEID may be encoded using mkey where mkey contains the non-negative tee.pceid and mval.name contains the $tee-pceid-type value.¶

8.2.13. The tee-svn-type Measurement Extension

The tee.isvsvn extension enables the Attester to report the SVN for the independent software vendor supplied component as Evidence and the RVP to assert a Reference Value that is greater-than-or-equal to the reported SVN.¶

The $tee-svn-type is either an unsigned integer when reported as Evidence, or a tagged numeric expression that contains an SVN and a numeric greater-than-or-equal operator. The Verifier ensures the Evidence value is greater-that-or-equal to the Reference Value.¶

The $tee-svn-type is a svn-type when used as Endorsement or Evidence and a tagged-numeric-expression when used as a Reference Value.¶

$$measurement-values-map-extension //= (
  &(tee.isvsvn: -73) => $tee-svn-type
)
$tee-svn-type /= svn-type .within numeric-type
$tee-svn-type /= tagged-numeric-ge

Alternatively, the TEE isvsvn may be encoded using mkey where mkey contains the non-negative tee.isvsvn and mval.svn contains the svn value as svn-type.¶

8.2.14. The tee-tcb-comp-svn-type Measurement Extension

The tee.tcb-comp-svn extension enables the Attester to report an array of SVN values for the TCB when asserted as Evidence and an array of tagged-numeric-ge entries when asserted as a Reference Value.¶

The $tee-tcb-comp-svn-type is an array containing 16 SVN values when reported as Evidence and an array of 16 expression records each containing the numeric ge operator and a reference SVN value. The Verifier evaluates each SVN in the Evidence array with the corresponding reference expression, by array position. If all Evidence values match their respective expressions, evaluation is successful. The array of SVN Evidence is accepted.¶

$$measurement-values-map-extension //= (
  &(tee.tcb-comp-svn: -125) => $tee-tcb-comp-svn-type
)
$tee-tcb-comp-svn-type /=
  [ 16*16 svn-type .within numeric-type ]
$tee-tcb-comp-svn-type /=
  [ 16*16 tagged-numeric-ge ]

8.2.15. The tee-tcb-eval-num-type Measurement Extension

The tee.tcb-eval-num extension enables the Attester to report a TCB evaluation number as Evidence and the RVP to assert a Reference Value expression that compares the tcb-eval-num Evidence with the Reference Value using the greater-than-or-equal operator.¶

The $tee-tcb-eval-num-type is an unsigned integer when reported as Evidence and a tagged numeric expression when asserted as Reference Values.¶

$$measurement-values-map-extension //= (
  &(tee-tcb-eval-num: -86) => $tee-tcb-eval-num-type
)
$tee-tcb-eval-num-type /= uint .within numeric-type
$tee-tcb-eval-num-type /= tagged-numeric-ge

Alternatively, the TEE tcb-eval-num Evidence may be encoded using mkey where mkey contains the non-negative tee.tcb-eval-num and mval.raw-value contains the tcb-eval-num encoded as 4-byte bstr value.¶

8.2.16. The tee-tcbstatus-type Measurement Extension

The tee.tcb-status extension enables Attesters to report the status of the TEE trusted computing base (TCB) and for Reference Value Providers (RVP) to assert expected TCB status. It can also be used by Endorsers to assert TCB status through conditional endorsement.¶

The tee-tcbstatus-type is used to specify TCB status as a set of status strings or as an expression with a set membership operator.¶

The $tee-tcbstatus-type is a status array containing strings describing TCB status values. When describing Evidence the set-tstr-type type is used. When describing Reference Values or Endorsements the set-tstr-type, tagged-exp-tstr-member, or tagged-exp-tstr-not-member types can be used.¶

$$measurement-values-map-extension //= (
  &(tee.tcbstatus: -88) => $tee-tcbstatus-type
)
$tee-tcbstatus-type /= set-tstr-type
$tee-tcbstatus-type /= tagged-exp-tstr-member
$tee-tcbstatus-type /= tagged-exp-tstr-not-member

8.2.16.1. The tee-tcbstatus-type Comparison Algorithm

The comparison algorithm for tee-tcbstatus-type is used when Endorsement or Reference Values triples conditions are matched with an Environment Claims Tuple (ECT) in the Verifier's Accepted Claims Set (ACS). The triple condition containing a tee-tcbstatuss-type Claim matches an ACS ECT according to the comparison algorithm for set of strings as defined in Section 9.2.¶

8.2.17. The tee-vendor-type Measurement Extension

The tee.vendor extension enables the Attester to report the TEE vendor name as Evidence and for the RVP to assert the TEE vendor name.¶

The $tee-vendor-type is a string containing the vendor name as a string. The vendor string in Evidence must exactly match the vendor string in Reference Values.¶

The $tee-vendor-type is an exact match measurement.¶

$$measurement-values-map-extension //= (
  &(tee.vendor: -70) => $tee-vendor-type
)
$tee-vendor-type /= tstr

Alternatively, the TEE vendor may be encoded using mkey where mkey contains the non-negative tee.vendor and mval.name contains the $tee-vendor-type value.¶

9. Appraisal Algorithm

The Intel profile anticipates appraisal algorithms will be based on the appraisal algorithm defined in [I-D.ietf-rats-corim]. This profile extends the appraisal algorithm to recognize profile extensions that form equations. An Evidence measurement forms one of the operands: (evidence operand). A Reference Value forms the operator and remaining operands: [(expression operator), (reference value operand), ...]. For example, if a numeric reference value is 14, and the expressions operator is gt the Reference Value might contain the Claim: #6.60010([ 1, 14]). Evidence might contain the measurement: '15'. In infix construction, the equation would be: (15) (gt) (14). The Verifier evaluates whether 15 is greater-than 14.¶

9.1. Complex Expressions

Complex expressions can be used to assess whether the Target Environment is in a particular state before certain Endorsement claims can be asserted. For example, if an SGX enclave has an svn value that is less than the prescribed minimum svn, the enclave status may be considered "OutOfDate" or may have a known security advisory. The CoMID conditional-endorsement-triples or conditional-endorsement-series-triples describe complex Endorsement expressions.¶

This profile uses these triples with the reference measurement values extensions described in Section 8.2.¶

9.2. Comparison Algorithm for Sets

The comparison algorithm for sets describes set equivalence, set membership, and set difference (not membership). The Verifier's Accepted Claims Set (ACS) contains a list of Environment Claims Tuples (ECT)[I-D.ietf-rats-corim]. The condition ECTs are compared to ACS ECTs based on this comparison algorithm.¶

The set comparison algorithm processes sets of strings and sets of digests.¶

9.2.1. Comparison Algorithm for Set of Strings

There are three string set representations: set-tstr-type, tagged-exp-tstr-member, and tagged-exp-tstr-not-member.¶

set-tstr-type - Every string in the condition set-tstr-type MUST match a string in the ACS.ECT.element-map.element-claims.set-tstr-type set. The string position in the array is not significant. The ACS.ECT.element-map.element-claims.set-tstr-type set MUST be equivalent to the condition set-tstr-type set (i.e., the two sets have the same cardinality and the same set members).¶
tagged-exp-tstr-member - The condition ECT set operator MUST equal member and every string in the condition set-tstr-type MUST match a string in the ACS.ECT.element-map.element-claims.set-tstr-type set. The string position in the array is not significant. The ACS.ECT.element-map.element-claims.set-tstr-type set MAY contain strings not found in the condition set-tstr-type.¶
tagged-exp-tstr-not-member - The condition ECT set operator MUST equal not-member and every string in the condition set-tstr-type MUST NOT match a string in the ACS.ECT.element-map.element-claims.set-tstr-type set. The string position in the array is not significant.¶

9.2.2. Comparison Algorithm for Set of Digests

There are five digest set representations: digest, digest-type, set-digest-type, tagged-exp-digest-member, and tagged-exp-digest-not-member.¶

digest - The singleton digest in the condition MUST match at least one digest in the ACS.ECT.element-map.element-claims.set-digest-type set.¶
digest-type and set-digest-type - Every digest in the condition digest-type or set-digest-type MUST match a digest in the ACS.ECT.element-map.element-claims.set-digest-type set. The digest position in the array is not significant. The ACS.ECT.element-map.element-claims.set-digest-type set MUST be equivalent to the condition set-digest-type set (i.e., the two sets have the same cardinality and the same set members). Matching based on the empty set is permitted when the set-digest-type is used.¶
tagged-exp-digest-member - The condition ECT set operator MUST equal member and every digest in the condition set-digest-type MUST match a digest in the ACS.ECT.element-map.element-claims.set-digest-type set. The digest position in the array is not significant. The ACS.ECT.element-map.element-claims.set-digest-type set MAY contain digests not found in the condition set-digest-type.¶
tagged-exp-digest-not-member - The condition ECT set operator MUST equal not-member and every digest in the condition set-digest-type MUST NOT match a digest in the ACS.ECT.element-map.element-claims.set-digest-type set. The digest position in the array is not significant.¶

10. Reporting Attestation Results

Attestation verification can be performed by a pipeline consisting of multiple stages where each input manifest demarks a stage. The final stage prepares Attestation Results according to Relying Party specifications. This profile does not define an attestation results format. The Relying Party should specify suitable Attestation Results formats such as [I-D.ietf-rats-ar4si] or [I-D.kdyxy-rats-tdx-eat-profile].¶

The precise Attestation Results format used, if negotiated by Verifier and Relying Party, should reference this profile to acknowledge that the Relying Party and Verifier both support the extensions defined in this document.¶

11. Security Considerations

The security of this profile depends on the security considerations of the various normative references.¶

12. IANA Considerations

IANA is requested to allocate the following tags in the CBOR Tags registry [IANA.cbor-tags], preferably with the CBOR tag value requested.¶

Table 3
Tag	Data Item	Semantics	Reference
60010	`tag`	Numeric Expressions, see Section 8.1.2	RFCthis
60020	`tag`	Set digest Expressions, see Section 8.1.3	RFCthis
60021	`tag`	Set tstr Expressions, see Section 8.1.3	RFCthis
60030	`tag`	Time Expressions, see Section 8.1.4	RFCthis
60031	`tag`	Date Expressions, see Section 8.1.4	RFCthis
60032	`tag`	Epoch Expressions, see Section 8.1.4	RFCthis
60040	`tag`	Mask Expressions, see Section 8.1.5	RFCthis

13. References

13.1. Normative References

[DICE.Attest]: Trusted Computing Group (TCG), "DICE Attestation Architecture", Version 1.1, Revision 18 , January 2024, <https://trustedcomputinggroup.org/wp-content/uploads/DICE-Attestation-Architecture-Version-1.1-Revision-18_pub.pdf>.
[DICE.CoRIM]: Trusted Computing Group (TCG), "DICE Endorsement Architecture for Devices", Version 1.0, Revision 0.38 , November 2022, <https://trustedcomputinggroup.org/wp-content/uploads/TCG-Endorsement-Architecture-for-Devices-V1-R38_pub.pdf>.
[DICE.layer]: Trusted Computing Group (TCG), "DICE Layering Architecture", Version 1.0, Revision 0.19 , July 2020, <https://trustedcomputinggroup.org/wp-content/uploads/DICE-Layering-Architecture-r19_pub.pdf>.
[I-D.ietf-rats-corim]: Birkholz, H., Fossati, T., Deshpande, Y., Smith, N., and W. Pan, "Concise Reference Integrity Manifest", Work in Progress, Internet-Draft, draft-ietf-rats-corim-07, 3 March 2025, <https://datatracker.ietf.org/doc/html/draft-ietf-rats-corim-07>.
[I-D.ietf-rats-eat]: Lundblade, L., Mandyam, G., O'Donoghue, J., and C. Wallace, "The Entity Attestation Token (EAT)", Work in Progress, Internet-Draft, draft-ietf-rats-eat-31, 6 September 2024, <https://datatracker.ietf.org/doc/html/draft-ietf-rats-eat-31>.
[I-D.ietf-rats-msg-wrap]: Birkholz, H., Smith, N., Fossati, T., Tschofenig, H., and D. Glaze, "RATS Conceptual Messages Wrapper (CMW)", Work in Progress, Internet-Draft, draft-ietf-rats-msg-wrap-12, 28 February 2025, <https://datatracker.ietf.org/doc/html/draft-ietf-rats-msg-wrap-12>.
[IANA.cbor-tags]: IANA, "Concise Binary Object Representation (CBOR) Tags", <https://www.iana.org/assignments/cbor-tags>.
[RFC2119]: Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174]: Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[TCG.CE]: Trusted Computing Group (TCG), "TCG DICE Concise Evidence Binding for SPDM", Version 1.0, Revision 0.54 , January 2024, <https://trustedcomputinggroup.org/wp-content/uploads/TCG-DICE-Concise-Evidence-Binding-for-SPDM-Version-1.0-Revision-54_pub.pdf>.

13.2. Informative References

[DICE.engine]: Trusted Computing Group (TCG), "Requirements for a Device Identifier Composition Engine", Family "2.0", Level 00 Revision 78 , March 2018, <https://trustedcomputinggroup.org/wp-content/uploads/Hardware-Requirements-for-Device-Identifier-Composition-Engine-r78_For-Publication.pdf>.
[DMTF.SPDM]: Distributed Managability Task Force (DMTF), "Security Protocol and Data Mmodel (SPDM) Specification", Version 1.2.1 , May 2022, <https://www.dmtf.org/sites/default/files/standards/documents/DSP0274_1.2.1.pdf>.
[I-D.birkholz-rats-epoch-markers]: Birkholz, H., Fossati, T., Pan, W., and C. Bormann, "Epoch Markers", Work in Progress, Internet-Draft, draft-birkholz-rats-epoch-markers-08, 22 July 2024, <https://datatracker.ietf.org/doc/html/draft-birkholz-rats-epoch-markers-08>.
[I-D.ietf-rats-ar4si]: Voit, E., Birkholz, H., Hardjono, T., Fossati, T., and V. Scarlata, "Attestation Results for Secure Interactions", Work in Progress, Internet-Draft, draft-ietf-rats-ar4si-08, 6 February 2025, <https://datatracker.ietf.org/doc/html/draft-ietf-rats-ar4si-08>.
[I-D.ietf-rats-endorsements]: Thaler, D., Birkholz, H., and T. Fossati, "RATS Endorsements", Work in Progress, Internet-Draft, draft-ietf-rats-endorsements-06, 3 March 2025, <https://datatracker.ietf.org/doc/html/draft-ietf-rats-endorsements-06>.
[I-D.kdyxy-rats-tdx-eat-profile]: Kostal, G., Dittakavi, S., Yeluri, R., Xia, H., and J. Yu, "EAT profile for Intel(r) Trust Domain Extensions (TDX) attestation result", Work in Progress, Internet-Draft, draft-kdyxy-rats-tdx-eat-profile-02, 13 December 2024, <https://datatracker.ietf.org/doc/html/draft-kdyxy-rats-tdx-eat-profile-02>.
[INTEL.DCAP]: Intel Corporation, "Intel(R) Software Guard Extensions (Intel(R) SGX) Data Center Attestation Primitives ECDSA Quote Library API", August 2023, <https://download.01.org/intel-sgx/latest/dcap-latest/linux/docs/Intel_SGX_ECDSA_QuoteLibReference_DCAP_API.pdf>.
[RFC5280]: Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, <https://www.rfc-editor.org/rfc/rfc5280>.
[RFC8392]: Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, "CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392, May 2018, <https://www.rfc-editor.org/rfc/rfc8392>.
[RFC9334]: Birkholz, H., Thaler, D., Richardson, M., Smith, N., and W. Pan, "Remote ATtestation procedureS (RATS) Architecture", RFC 9334, DOI 10.17487/RFC9334, January 2023, <https://www.rfc-editor.org/rfc/rfc9334>.

Appendix A. Acknowledgments

The authors wish to thank Shanwei Cen, Piotr Zmijewski, Francisco J. Chinchilla and Dionna Amalie Glaze for their valuable contributions.¶

Appendix B. Full Intel Profile CDDL

tagged-numeric-gt = #6.60010( [
    op.gt .within numeric-operators,
    reference-value: numeric-type ] )
tagged-numeric-ge = #6.60010( [
    op.ge .within numeric-operators,
    reference-value: numeric-type ] )
tagged-numeric-lt = #6.60010( [
    op.lt .within numeric-operators,
    reference-value: numeric-type ] )
tagged-numeric-le = #6.60010( [
    op.le .within numeric-operators,
    reference-value: numeric-type ] )

numeric-type = integer / unsigned / float
numeric-operators /= op.gt
numeric-operators /= op.ge
numeric-operators /= op.lt
numeric-operators /= op.le
numeric-expression = [ numeric-operators, numeric-type ]
tagged-numeric-expression = #6.60010(numeric-expression)

member = 6
not-member = 7
set-operators /= op.mem
set-operators /= op.nmem

set-digest-type /= [ * digest ]
set-digest-expression = [ set-operators, set-digest-type ]
tagged-set-digest-expression = #6.60020( set-digest-expression )

set-tstr-type /= [ * tstr ]
set-tstr-expression = [ set-operators, set-tstr-type ]
tagged-set-tstr-expression = #6.60021( set-tstr-expression )

tagged-exp-digest-member = #6.60020([
    op.mem .within set-operators, set-digest-type ])

tagged-exp-digest-not-member = #6.60020([
    op.nmem .within set-operators, set-digest-type ])

tagged-exp-tstr-member = #6.60021([
    op.mem .within set-operators, set-tstr-type ])

tagged-exp-tstr-not-member = #6.60021([
    op.nmem .within set-operators, set-tstr-type ])

subset = 8
superset = 9
disjoint = 10
set-of-set-type = [ * [ + any ]]
set-of-set-operator = subset / superset / disjoint
set-of-set-expression = [ set-of-set-operator, set-of-set-type ]
tagged-set-of-set-expression = #6.60020(set-of-set-expression)

tagged-exp-subset = #6.60010([
    subset .within set-of-set-operator, set-of-set-type ])

tagged-exp-superset = #6.60010([
    superset .within set-of-set-operator, set-of-set-type ])

tagged-exp-disjoint = #6.60010([
    disjoint .within set-of-set-operator, set-of-set-type ])

mask-operators /= op.eq
mask-type = bstr
mask-expression = [ mask-operators, value: mask-type, mask: mask-type]
tagged-mask-expression = #6.60040( mask-expression )

tagged-exp-mask-eq = #6.60040([ op.eq .within mask-operators, value: mask-type, mask: mask-type ] )

tagged-exp-tdate-gt = #6.60031([
    op.gt .within tdate-operators,
    tdate-type ])

tagged-exp-tdate-ge = #6.60031([
    op.ge .within tdate-operators,
    tdate-type ])

tagged-exp-tdate-lt = #6.60031([
    op.lt .within tdate-operators,
    tdate-type ])

tagged-exp-tdate-le = #6.60031([
    op.le .within tdate-operators,
    tdate-type ])

tdate-operators /= op.gt
tdate-operators /= op.ge
tdate-operators /= op.lt
tdate-operators /= op.le
tdate-type = ~tdate
tdate-expression = [ tdate-operators, tdate-type ] ;#6.0(string) - tdate converts to numeric
tagged-tdate-expression = #6.60031( tdate-expression )

tagged-exp-time-eq = #6.60030([
    op.eq .within time-operators,
    time-type ])

tagged-exp-time-gt = #6.60030([
    op.gt .within time-operators,
    time-type ])

tagged-exp-time-ge = #6.60030([
    op.ge .within time-operators,
    time-type ])

tagged-exp-time-lt = #6.60030([
    op.lt .within time-operators,
    time-type ])

tagged-exp-time-le = #6.60030([
    op.le .within time-operators,
    time-type ])

time-operators /= op.eq
time-operators /= op.gt
time-operators /= op.ge
time-operators /= op.lt
time-operators /= op.le
time-type = ~time
time-expression = [ time-operators, time-type ] ;#6.1(int or float)
tagged-time-expression = #6.60030( time-expression )

tagged-exp-epoch-gt = #6.60032([
    op.gt .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-ge = #6.60032([
    op.ge .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-lt = #6.60032([
    op.lt .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-le = #6.60032([
    op.le .within epoch-operators
    grace-period: epoch-seconds-type ])

tagged-exp-epoch-id-gt = #6.60032([
    op.gt .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

tagged-exp-epoch-id-ge = #6.60032([
    op.ge .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

tagged-exp-epoch-id-lt = #6.60032([
    op.lt .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

tagged-exp-epoch-id-le = #6.60032([
    op.le .within epoch-operators
    grace-period: epoch-seconds-type,
    epoch-id: $tagged-epoch-id ])

epoch-operators /= op.eq
epoch-operators /= op.gt
epoch-operators /= op.ge
epoch-operators /= op.lt
epoch-operators /= op.le
epoch-seconds-type = ~time
$tagged-epoch-id /= tdate ; string - converted to ~time for comparisons
$tagged-epoch-id /= time ; int or float
$epoch-timestamp-type /= ~tdate
$epoch-timestamp-type /= ~time
epoch-expression = [
    epoch-operators,
    grace-period: epoch-seconds-type,
    ? epoch-id: $tagged-epoch-id
]
tagged-epoch-expression = #6.60032( epoch-expression )

$$measurement-values-map-extension //= (
  &(tee.advisory-ids: -89) => $tee-advisory-ids-type
)
$tee-advisory-ids-type /= set-tstr-type
$tee-advisory-ids-type /= tagged-exp-tstr-not-member
$tee-advisory-ids-type /= tagged-exp-tstr-member

$$measurement-values-map-extension //= (
  &(tee.attributes: -82) => $tee-attributes-type
)
$tee-attributes-type /= mask-type
$tee-attributes-type /= tagged-exp-mask-eq

$$measurement-values-map-extension //= (
  &(tee.cryptokeys: -91) => [ + $tee-cryptokey-type ]
)
$tee-cryptokey-type /= $crypto-key-type-choice

$$measurement-values-map-extension //= (
  &(tee.tcbdate: -72) => $tee-date-type
)
$tee-date-type /= tdate-type
$tee-date-type /= tagged-exp-tdate-ge

$$measurement-values-map-extension //= (
  &(tee.mrtee: -83) => $tee-digest-type
)
$$measurement-values-map-extension //= (
  &(tee.mrsigner: -84) => $tee-digest-type
)
$tee-digest-type /= digest ; see corim
$tee-digest-type /= digests-type ; see corim
$tee-digest-type /= set-digest-type
$tee-digest-type /= tagged-exp-digest-member
$tee-digest-type /= tagged-exp-digest-not-member

$$measurement-values-map-extension //= (
  &(tee.epoch: -90) => $tee-epoch-type
)
$tee-epoch-type /= $epoch-timestamp-type
$tee-epoch-type /= tagged-exp-epoch-gt
$tee-epoch-type /= tagged-exp-epoch-ge
$tee-epoch-type /= tagged-exp-epoch-lt
$tee-epoch-type /= tagged-exp-epoch-le
$tee-epoch-type /= tagged-exp-epoch-id-gt
$tee-epoch-type /= tagged-exp-epoch-id-ge
$tee-epoch-type /= tagged-exp-epoch-id-lt
$tee-epoch-type /= tagged-exp-epoch-id-le

$$measurement-values-map-extension //= (
  &(tee.instance-id: -77) => $tee-instance-id-type
)
$tee-instance-id-type /= uint
$tee-instance-id-type /= bstr

$$measurement-values-map-extension //= (
  &(tee.isvprodid: -85) => $tee-isvprodid-type
)
$tee-isvprodid-type /= uint
$tee-isvprodid-type /= bstr

$$measurement-values-map-extension //= (
  &(tee.miscselect: -81) => $tee-miscselect-type
)
$tee-miscselect-type /= mask-type
$tee-miscselect-type /= tagged-exp-mask-eq

$$measurement-values-map-extension //= (
  &(tee.model: -71) => $tee-model-type
)
$tee-model-type /= tstr

op.eq=0
op.gt=1
op.ge=2
op.lt=3
op.le=4
op.mem=6
op.nmem=7
op.sub=8
op.sup=9
op.dif=10

$$measurement-values-map-extension //= (
  &(tee.pceid: -80) => $tee-pceid-type
)
$tee-pceid-type /= tstr

$$measurement-values-map-extension //= (
  &(tee.isvsvn: -73) => $tee-svn-type
)
$tee-svn-type /= svn-type .within numeric-type
$tee-svn-type /= tagged-numeric-ge

$$measurement-values-map-extension //= (
  &(tee.tcb-comp-svn: -125) => $tee-tcb-comp-svn-type
)
$tee-tcb-comp-svn-type /=
  [ 16*16 svn-type .within numeric-type ]
$tee-tcb-comp-svn-type /=
  [ 16*16 tagged-numeric-ge ]

$$measurement-values-map-extension //= (
  &(tee-tcb-eval-num: -86) => $tee-tcb-eval-num-type
)
$tee-tcb-eval-num-type /= uint .within numeric-type
$tee-tcb-eval-num-type /= tagged-numeric-ge

$$measurement-values-map-extension //= (
  &(tee.tcbstatus: -88) => $tee-tcbstatus-type
)
$tee-tcbstatus-type /= set-tstr-type
$tee-tcbstatus-type /= tagged-exp-tstr-member
$tee-tcbstatus-type /= tagged-exp-tstr-not-member

$$measurement-values-map-extension //= (
  &(tee.vendor: -70) => $tee-vendor-type
)
$tee-vendor-type /= tstr

$$measurement-values-map-extension //= (
  &(tee.platform-instance-id: -101) => $tee-platform-instance-id-type
)
$tee-platform-instance-id-type /= bstr