Internet DRAFT - draft-santesson-svt
draft-santesson-svt
Network Working Group S. Santesson
Internet-Draft IDsec Solutions
Intended status: Informational R. Housley
Expires: 18 November 2022 Vigil Security
17 May 2022
Signature Validation Token
draft-santesson-svt-08
Abstract
Electronic signatures have a limited lifespan with respect to the
time period that they can be validated and determined to be
authentic. The Signature Validation Token (SVT) defined in this
specification provides evidence that asserts the validity of an
electronic signature. The SVT is provided by a trusted authority,
which asserts that a particular signature was successfully validated
according to defined procedures at a certain time. Any future
validation of that electronic signature can be satisfied by
validating the SVT without any need to also validate the original
electronic signature or the associated digital certificates. SVT
supports electronic signatures in CMS, XML, PDF and JSON documents.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on 18 November 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Signature Validation Token . . . . . . . . . . . . . . . . . 5
3.1. Signature Validation Token Function . . . . . . . . . . . 6
3.2. Signature Validation Token Syntax . . . . . . . . . . . . 7
3.2.1. Data Types . . . . . . . . . . . . . . . . . . . . . 7
3.2.2. Signature Validation Token JWT Claims . . . . . . . . 8
3.2.3. SigValidation Object Class . . . . . . . . . . . . . 9
3.2.4. Signature Claims Object Class . . . . . . . . . . . . 10
3.2.5. SigReference Claims Object Class . . . . . . . . . . 10
3.2.6. SignedDataReference Claims Object Class . . . . . . . 11
3.2.7. PolicyValidation Claims Object Class . . . . . . . . 11
3.2.8. TimeValidation Claims Object Class . . . . . . . . . 12
3.2.9. CertReference Claims Object Class . . . . . . . . . . 13
3.2.10. SVT JOSE Header . . . . . . . . . . . . . . . . . . . 13
4. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1. Defined Profiles . . . . . . . . . . . . . . . . . . . . 15
5. Signature Verification with a SVT . . . . . . . . . . . . . . 15
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
6.1. Claim Names Registration . . . . . . . . . . . . . . . . 16
6.1.1. Registry Contents . . . . . . . . . . . . . . . . . . 16
6.2. Header Parameter Names Registration . . . . . . . . . . . 16
6.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
7.1. Level of reliance . . . . . . . . . . . . . . . . . . . . 17
7.2. Aging algorithms . . . . . . . . . . . . . . . . . . . . 17
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1. Normative References . . . . . . . . . . . . . . . . . . 17
8.2. Informative References . . . . . . . . . . . . . . . . . 19
Appendix A. Appendix: XML signature profile . . . . . . . . . . 19
A.1. Notation . . . . . . . . . . . . . . . . . . . . . . . . 20
A.1.1. References to XML Elements from XML Schemas . . . . . 20
A.2. SVT in XML Documents . . . . . . . . . . . . . . . . . . 20
A.2.1. SignatureValidationToken Signature Property . . . . . 20
A.2.2. Multiple SVT in an XML signature . . . . . . . . . . 22
A.3. XML signature SVT Claims . . . . . . . . . . . . . . . . 22
A.3.1. XML Profile Identifier . . . . . . . . . . . . . . . 22
A.3.2. XML Signature Reference Data . . . . . . . . . . . . 22
A.3.3. XML Signed Data Reference Data . . . . . . . . . . . 23
A.3.4. XML Signer Certificate References . . . . . . . . . . 23
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A.4. JOSE Header . . . . . . . . . . . . . . . . . . . . . . . 23
A.4.1. SVT Signing Key Reference . . . . . . . . . . . . . . 23
Appendix B. Appendix: PDF signature profile . . . . . . . . . . 24
B.1. SVT in PDF Documents . . . . . . . . . . . . . . . . . . 24
B.1.1. SVT Extension to Timestamp Tokens . . . . . . . . . . 24
B.2. PDF signature SVT Claims . . . . . . . . . . . . . . . . 25
B.2.1. PDF Profile Identifier . . . . . . . . . . . . . . . 25
B.2.2. PDF Signature Reference Data . . . . . . . . . . . . 25
B.2.3. PDF Signed Data Reference Data . . . . . . . . . . . 25
B.2.4. PDF Signer Certificate References . . . . . . . . . . 25
B.3. JOSE Header . . . . . . . . . . . . . . . . . . . . . . . 26
B.3.1. SVT Signing Key Reference . . . . . . . . . . . . . . 26
Appendix C. Appendix: JWS Profile . . . . . . . . . . . . . . . 26
C.1. SVT in JWS . . . . . . . . . . . . . . . . . . . . . . . 27
C.1.1. "svt" Header Parameter . . . . . . . . . . . . . . . 27
C.1.2. Multiple SVT in a JWS signature . . . . . . . . . . . 27
C.2. JWS signature SVT Claims . . . . . . . . . . . . . . . . 27
C.2.1. JWS Profile Identifier . . . . . . . . . . . . . . . 28
C.2.2. JWS Signature Reference Data . . . . . . . . . . . . 28
C.2.3. JWS Signed Data Reference Data . . . . . . . . . . . 28
C.2.4. JWS Signer Certificate References . . . . . . . . . . 28
C.3. SVT JOSE Header . . . . . . . . . . . . . . . . . . . . . 29
C.3.1. SVT Signing Key Reference . . . . . . . . . . . . . . 29
Appendix D. Appendix: Schemas . . . . . . . . . . . . . . . . . 29
D.1. Concise Data Definition Language (CDDL) . . . . . . . . . 29
D.2. JSON Schema . . . . . . . . . . . . . . . . . . . . . . . 31
Appendix E. Appendix: Examples . . . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39
1. Introduction
Electronic signatures have a limited lifespan regarding when they can
be validated and determined to be authentic. Many factors make it
more difficult to validate electronic signatures over time. For
example:
* Trusted information about the validity of the certificate
containing the signer's public key is not available.
* Trusted information about the date and time when the signature was
actually created is not available.
* Algorithms used to create the electronic signature may no longer
be considered secure at the time of validation and may therefore
no longer be available in software libraries.
* Services necessary to validate the signature are no longer
available at the time of validation.
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* Supporting evidence such as CA certificates, OCSP responses, CRLs,
or timestamps.
The challenges to validation of an electronic signature increases
over time, and eventually it may simply be impossible to verify the
signature with a sufficient level of assurance.
Existing standards, such as the ETSI XAdES [XADES] profile for XML
signatures [XMLDSIG11], ETSI PAdES [PADES] profile for PDF signatures
[ISOPDF2], and ETSI CAdES [CADES] profile for CMS signatures
[RFC5652] can be used to extend the time within which a signature can
be validated at the cost of significant complexity which involves
storing and validating significant amounts of external evidence data
such as revocation data, signature time stamps and archival time
stamps.
The Signature Validation token (SVT) defined in this specification
takes a trusted signature validation process as an input and
preserves the validation result for the associated signature and
signed document. The SVT asserts that a particular electronic
signature was successfully validated by a trusted authority according
to defined procedures at a certain date and time. Those procedures
MUST include checks that the signature match the signed document,
checks that the signature can be validated by the signing certificate
and checks that the signing certificate pass certificate path
validation [RFC5280]. Those procedures MAY also include checks
associated with a particular trust policy such as that an acceptable
certificate policy [RFC5280] [RFC3647] was used to issue the signer's
certificate and checks that an acceptable signature policy was used
by the signer [RFC3125].
Once the SVT is issued by a trusted authority, any future validation
of that electronic signature can be satisfied by validating the SVT,
without any need to also re-validate the original electronic
signature.
As SVT is used to preserve validation result obtained through
applying existing standards for signature validation, it is
complementary to and not a replacement for such standards, including
the ETSI standards for long term validation listed above. SVT do
however have the potentially positive effect that it may
significantly reduce the need to apply complex long-term validation
and preservation techniques for signature validation if an SVT is
issued and applied to the signed document at an early stage where the
signature can be validated without support of large amounts of
external evidence. The use of SVT may therefore drastically reduce
the complexity of re-validation of old archived electronic
signatures.
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The SVT can be signed with private keys and algorithms that provide
confidence for a considerable time period. In fact, multiple SVTs
can be used to offer greater assurance. For example, one SVT could
be produced with a large RSA private key, a second one with a strong
elliptic curve, and a third one with a quantum safe digital signature
algorithm to protect against advances in computing power and
cryptanalytic capabilities. Further, the trusted authority can add
additional SVTs in the future using fresh private keys and signatures
to extend the lifetime of the, if necessary.
2. 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.
This document use the following terms:
* Signed Data -- The data covered by a particular electronic
signature. This is typically equivalent to the signed content of
a document, and it represents the data that the signer intended to
sign. In some cases, such as in some XML signatures, the signed
data can be the collection of several data fragments each
referenced by the signature. In the case of PDF, this is the data
covered by the "ByteRange" parameter in the signature dictionary.
In JWS, this is the unencoded payload data (before base64url
encoding).
* Signed Bytes -- These are the actual bytes of data that were
hashed and signed by the digital signature algorithm. In most
cases, this is not the actual Signed Data, but a collection of
signature metadata that includes references (hash) of the Signed
Data as well as information about algorithms and other data bound
to a signature. In XML, this is the canonicalized SignedInfo
element. In CMS and PDF signatures, this is the DER-encoded
SignedAttributes structure. In JWS, this is the protected header
and payload data formatted according to [RFC7515].
When these terms are used as defined in this section, they appear
with a capitalized first letter.
3. Signature Validation Token
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3.1. Signature Validation Token Function
Signature Validation Token (SVT) is created by a trusted service to
assert evidence of successful electronic signature validation using a
well-defined and trustworthy signature validation process. The SVT
binds the validation result to the validated signature, the document
signed by the signature and the certificate of the signer. This
allows a relying party to verify the validity of a signed document
without having to re-validate the original signature or to re-use any
of its associated cryptographic algorithms for as long as the SVT
itself can be validated. The SVT achieves this by binding the
following information to a specific electronic signature:
* A unique identification of the electronic signature.
* The data and metadata signed by the electronic signature.
* The signer's certificate that was validated as part of electronic
signature verification.
* The certification path that was used to validate the signer's
certificate.
* An assertion providing evidence of that the signature was
verified, the date and time the verification was performed, the
procedures used to verify the electronic signature, and the
outcome of the verification.
* An assertion providing evidence of the date and time at which the
signature is known to have existed, the procedures used to
validate the date and time of existence, and the outcome of the
validation.
The SVT aims to support long term validation that can be further
extended into the future by applying the following strategies:
* By using secure algorithms with long life exepectancy when signing
the SVT.
* By re-issuing the SVT before it becomes insecure or is considered
expired.
* Optionally, by issuing multipple SVT:s with different algorithms
to provide redundancy in case one algorithm is broken.
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3.2. Signature Validation Token Syntax
The SVT is carried in a JSON Web Token (JWT) as defined in [RFC7519].
3.2.1. Data Types
The contents of claims in an SVT are specified using the following
data types:
* String -- JSON Data Type of string that contains an arbitrary case
sensitive string value.
* Base64Binary -- JSON Data Type of string that contains of Base64
encoded byte array of binary data.
* StringOrURI -- JSON Data Type of string that contains an arbitrary
string or an URI as defined in [RFC7519], which REQUIRES a value
containing the colon character (":") to be a URI.
* URI -- JSON Data Type of string that contains an URI as defined in
[RFC7519].
* Integer -- JSON Data Type of number that contains a 32-bit signed
integer value (from -2^31 to 2^31-1).
* Long -- JSON Data Type of number that contains a 64-bit signed
integer value (from -2^63 to 2^63-1).
* NumericDate -- JSON Data Type of number that contains a data as
defined in [RFC7519], which is the number of seconds from
1970-01-01T00:00:00Z UTC until the specified UTC date/time,
ignoring leap seconds.
* Boolean -- JSON Data Type of boolean that contains explicit value
of true or false.
* Object<Class> -- A JSON object holding a claims object of a class
defined in this specification (see Section 3.2.2).
* Map<Type> -- A JSON object with name-value pairs where the value
is an object of the specified Type in the notation. For example,
Map<String> is a JSON object with name value pairs where all
values are of type String.
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* Array -- A JSON array of a specific data type as defined in this
section. An array is expressed in this specification by square
brackets. For example, [String] indicates an array of String
values, and [Object<DocHash>] indicates an array of DocHash
objects.
* Null -- A JSON null that represents an absent value. A claim with
a null value is equivalent with an absent claim.
3.2.2. Signature Validation Token JWT Claims
The SVT MUST contain only JWT claims in the following list:
* jti -- A String data type that is a "JWT ID" registered claim
according to [RFC7519]. It is RECOMMENDED that the identifier
holds a hexadecimal string representation of a 128-bit unsigned
integer. A SVT MUST contain one "JWT ID" claim.
* iss -- A StringOrURI data type that is an "Issuer" registered
claim according to [RFC7519], which is an arbitrary unique
identifier of the SVT issuer. This value SHOULD have the value of
an URI based on a domain owned by the issuer. A SVT MUST contain
one "Issuer" claim.
* iat -- A NumericDate data type that is an "Issued At" registered
claim according to [RFC7519], which expresses the date and time
when this SVT was issued. A SVT MUST contain one "Issued At"
claim.
* aud -- A [StringOrURI] data type or a StringOrURI data type that
is an "Audience" registered claim according to [RFC7519]. The
audience claim is an array of one or more identifiers, identifying
intended recipients of the SVT. Each identifier MAY identify a
single entity, a group of entities or a common policy adopted by a
group of entities. If only one value is provided it MAY be
provided as a single StringOrURI data type value instead of as an
array of values. Inclusion of the "Audience" claim in a SVT is
OPTIONAL.
* exp -- A NumericDate data type that is an "Expiration Time"
registered claim according to [RFC7519], which expresses the date
and time when services and responsibilities related to this SVT is
no longer provided by the SVT issuer. The precise meaning of the
expiration time claim is defined by local policies. See
implementation note below. Inclusion of the "Expiration Time"
claim in a SVT is OPTIONAL.
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* sig_val_claims -- A Object<SigValidation> data type that contains
signature validation claims for this SVT extending the standard
registered JTW claims above. A SVT MUST contain one
sig_val_claims claim.
Note: An SVT asserts that a particular validation process was
undertaken at a stated date and time. This fact never changes and
never expires. However, some other aspects of the SVT such as
liability for false claims or service provision related to a specific
SVT may expire after a certain period of time, such as a service
where an old SVT can be upgraded to a new SVT signed with fresh keys
and algorithms.
3.2.3. SigValidation Object Class
The sig_val_claims JWT claim uses the SigValidation object class. A
SigValidation object holds all custom claims, and a SigValidation
object contains the following parameters:
* ver -- A String data type representing the version. This
parameter MUST be present, and the version in this specification
indicated by the value "1.0".
* profile -- A StringOrURI data type representing the name of a
profile that defines conventions followed for specific claims and
any extension points used by the SVT issuer. This parameter MUST
be present.
* hash_algo -- A URI data type that identifies the hash algorithm
used to compute the hash values within the SVT. The URI
identifier MUST be one defined in [RFC6931] or in the IANA
registry defined by this specification. This parameter MUST be
present.
* sig -- A [Object<Signature>] data type that gives information
about validated electronic signatures as an array of Signature
objects. If the SVT contains signature validation evidence for
more than one signature, then each signature is represented by a
separate Signature object. At least one Signature object MUST be
present.
* ext -- A Map<String> data type that provides additional claims
related to the SVT. Extension claims are added at the discretion
of the SVT issuer; however, extension claims MUST follow any
conventions defined in a profile of this specification (see
Section 4). Inclusion of this parameter is OPTIONAL.
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3.2.4. Signature Claims Object Class
The sig parameter in the SigValidation object class uses the
Signature object class. The Signature object contains claims related
to signature validation evidence for one signature, and it contains
the following parameters:
* sig_ref -- A Object<SigReference> data type that contains
reference information identifying the target signature. This
parameter MUST be present.
* sig_data_ref -- A [Object<SignedDataReference>] data type that
contains an array of references to Signed Data that was signed by
the target electronic signature. At least one SignedDataReference
object MUST be present.
* signer_cert_ref -- A Object<CertReference> data type that
references the signer's certificate and optionally reference to a
supporting certification path that was used to verify the target
electronic signature. This parameter MUST be present.
* sig_val -- A [Object<PolicyValidation>] data type that contains an
array of results of signature verification according to defined
procedures. At least one PolicyValidation object MUST be present.
* time_val -- A [Object<TimeValidation>] data type that contains an
array of time verification results that the target signature has
existed at a specific date and time in the past. Inclusion of
this parameter is OPTIONAL.
* ext -- A MAP<String> data type that provides additional claims
related to the target signature. Extension claims are added at
the discretion of the SVT Issuer; however, extension claims MUST
follow any conventions defined in a profile of this specification
(see Section 4). Inclusion of this parameter is OPTIONAL.
3.2.5. SigReference Claims Object Class
The sig_ref parameter in the Signature object class uses the
SigReference object class. The SigReference object provides
information used to match the Signature claims object to a specific
target electronic signature and to verify the integrity of the target
signature value and Signed Bytes, and it contains the following
parameters:
* id -- A String data type that contains an identifier assigned to
the target signature. Inclusion of this parameter is OPTIONAL.
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* sig_hash -- A Base64Binary data type that contains a hash value of
the target electronic signature value. This parameter MUST be
present.
* sb_hash -- A Base64Binary data type that contains a hash value of
the Signed Bytes of the target electronic signature. This
parameter MUST be present.
3.2.6. SignedDataReference Claims Object Class
The sig_data_ref parameter in the Signature object class uses the
SignedDataReference object class. The SignedDataReference object
provides information used to verify the target electronic signature
references to Signed Data as well as to verify the integrity of all
data that is signed by the target signature, and it contains the
following parameters:
* ref -- A String data type that contains a reference identifier for
the data or data fragment covered by the target electronic
signature. This parameter MUST be present.
* hash -- A Base64Binary data type that contains the hash value for
the data covered by the target electronic signature. This
parameter MUST be present.
3.2.7. PolicyValidation Claims Object Class
The sig_val parameter in the Signature object class uses the
PolicyValidation object class. The PolicyValidation object provides
information about the result of a validation process according to a
spefific policy, and it contains the following parameters:
* pol -- A StringOrURI data type that contains the identifier of the
policy governing the electronic signature verification process.
This parameter MUST be present.
* res -- A String data type that contains the result of the
electronic signature verification process. The value MUST be one
of "PASSED", "FAILED" or "INDETERMINATE" as defined by
[ETSI319102-1]. This parameter MUST be present.
* msg -- A String data type that contains a message describing the
result. Inclusion of this parameter is OPTIONAL.
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* ext -- A MAP<String> data type that provides additional claims
related to the target signature. Extension claims are added at
the discretion of the SVT Issuer; however, extension claims MUST
follow any conventions defined in a profile of this specification
(see Section 4). Inclusion of this parameter is OPTIONAL.
3.2.8. TimeValidation Claims Object Class
The time_val parameter in the Signature object class uses the
TimeValidation object class. The TimeValidation claims object
provides information about the result of validating evidence of time
asserting that the target signature existed at a particular date and
time in the past. Evidence of time is typically a timestamp
according to [RFC3161] but other types of evidence may be used such
as a previously issued SVT for this signature. The TimeValidation
claims object contains the following parameters:
* time -- A NumericDate data type that contains the verified time.
This parameter MUST be present.
* type -- A StringOrURI data type that contains an identifier of the
type of evidence of time. This parameter MUST be present.
* iss -- A StringOrURI data type that contains an identifier of the
entity that issued the evidence of time. This parameter MUST be
present.
* id -- A String data type that contains an unique identifier
assigned to the evidence of time. Inclusion of this parameter is
OPTIONAL.
* hash -- A Base64Binary data type that contains the hash value of
the validated evidence of time. Inclusion of this parameter is
OPTIONAL.
* val -- A [Object<PolicyValidation>] data type that contains an
array of results of the time evidence validation according to
defined validation procedures. Inclusion of this parameter is
OPTIONAL.
* ext -- A MAP<String> data type that provides additional claims
related to the target signature. Extension claims are added at
the discretion of the SVT Issuer; however, extension claims MUST
follow any conventions defined in a profile of this specification
(see Section 4). Inclusion of this parameter is OPTIONAL.
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3.2.9. CertReference Claims Object Class
The signer_cert_ref parameter in the Signature object class uses the
CertReference object class. The CertReference object references a
single X.509 certificate or a X.509 certification path, either by
providing the certificate data or by providing hash references for
certificates that can be located in the target electronic signature,
and it contains the following parameters:
* type -- A StringOrURI data type that contains an identifier of the
type of reference. The type identifier MUST be one of the
identifiers defined below, an identifier specified by the selected
profile, or a URI identifier. This parameter MUST be present.
* ref -- A [String] data type that contains an array of string
parameters according to conventions defined by the type
identifier. At least one parameter MUST be present.
The following type identifiers are defined:
* chain -- The ref contains an array of Base64 encoded X.509
certificates [RFC5280]. The certificates MUST be provided in the
order starting with the end entity certificate. Any following
certificate must be able to validate the signature on the previous
certificate in the array.
* chain_hash -- The ref contains an array of one or more Base64
encoded hash values where each hash value is a hash over a X.509
certificate [RFC5280] used to validate the signature. The
certificates MUST be provided in the order starting with the end
entity certificate. Any following certificate must be able to
validate the signature on the previous certificate in the array.
This option MUST NOT be used unless all hashed certificates are
present in the target electronic signature.
Note: All certificates referenced using the identifiers above are
X.509 certificates. Profiles of this specification MAY define
alternative types of public key containers; however, a major function
of these referenced certificates is not just to reference the public
key, but also to provide the subject name of the signer. It is
therefore important for the full function of an SVT that the
referenced public key container also provides the means to identify
of the signer.
3.2.10. SVT JOSE Header
The SVT JWT MUST contain the following JOSE header parameters in
accordance with Section 5 of [RFC7519]:
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* typ -- This parameter MUST have the string value "JWT" (upper
case).
* alg -- This parameter identifies the algorithm used to sign the
SVT JWT. The algorithm identifier MUST be specified in [RFC7518]
or the IANA JSON Web Signature and Encryption Algorithms Registry
[ add a ref ]. The specified signature hash algorithm MUST be
identical to the hash algorithm specified in the hash_algo
parameter of the SigValidation object within the sig_val_claims
claim.
The SVT header MUST contain a public key or a reference to a public
key used to verify the signature on the SVT in accordance with
[RFC7515]. Each profile, as discussed in Section 4, MUST define the
requirements for how the key or key reference is included in the
header.
4. Profiles
Each signed document and signature type will have to define the
precise content and use of several claims in the SVT.
Each profile MUST as a minimum define:
* The identifier of the profile.
* How to reference the Signed Data content of the signed document.
* How to reference to the target electronic signature and the Signed
Bytes of the signature.
* How to reference certificates supporting each electronic
siganture.
* How to include public keys or references to public keys in the
SVT.
* Whether each electronic signature is supported by a single SVT, or
whether one SVT may support multiple electronic signatures of the
same document.
A profile MAY also define:
* Explicit information on how to perform signature validation based
on an SVT.
* How to attach an SVT to an electronic signature or signed
document.
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4.1. Defined Profiles
The following profiles are defined in Appendixes of this document:
* Appendix A: XML Profile
* Appendix B: PDF Profile
* Appendix C: JWS Profile
Other documents MAY define other profiles that MAY complement, ammend
or supersede these profiles.
5. Signature Verification with a SVT
Signature verification based on an a SVT MUST follow these steps:
1. Locate all available SVTs available for the signed document that
are relevant for the target electronic signature.
2. Select the most recent SVT that can be successfully validated and
meets the requirement of the relying party.
3. Verify the integrity of the signature and the Signed Bytes of the
target electronic signature using the sig_ref claim.
4. Verify that the Signed Data reference in the original electronic
signature matches the reference values in the sig_data_ref claim.
5. Verify the integrity of referenced Signed Data using provided
hash values in the sig_data_ref claim.
6. Obtain the verified certificates supporting the asserted
electronic signature verification through the signer_cert_ref
claim.
7. Verify that signature validation policy results satisfy the
requirements of the relying party.
8. Verify that verified time results satisfy the context for the use
of the signed document.
After successfully performing these steps, signature validity is
established as well as the trusted signer certificate binding the
identity of the signer to the electronic signature.
6. IANA Considerations
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6.1. Claim Names Registration
This section registers the "sig_val_claims" claim name in the IANA
"JSON Web Token Claims" registry established by Section 10.1 in
[RFC7519].
6.1.1. Registry Contents
* Claim Name: "sig_val_claims"
* Claim Description: Signature Validation Token
* Change Controller: IESG
* Specification Document(s): Section 3.2.3 of {this document}
NOTE to RFC editor: Please replace {this document} with its assigned
RFC number.
6.2. Header Parameter Names Registration
This section registers the "svt" Header Parameter in the IANA "JSON
Web Signature and Encryption Header Parameters" registry established
by [RFC7515].
6.2.1. Registry Contents
* Header Parameter Name: "svt"
* Header Parameter Description: Signature Validation Token
* Header Parameter Usage Location(s): JWS
* Change Controller: IESG
* Specification Document(s): Appendix C.1.1 of {this document}
NOTE to RFC editor: Please replace {this document} with its assigned
RFC number.
7. Security Considerations
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7.1. Level of reliance
An SVT allows a signature verifier to still validate the original
signature using the original signature data and to use the
information in the SVT selectively to either just confirm the
validity and integrity of the original data, such as confirming the
integrity of signed data or the validity of the signer's certificate
etc.
Another way to use an SVT is to completely rely on the validation
conclusion provided by the SVT and to omit re-validation of the
original signature value and original certificate status checking
data.
This choice is a decision made by the verifier according to its own
policy and risk assessment.
However, even when relying on the SVT validation conclusion of an SVT
it is vital to still verify that the present SVT is correctly
associated with the document and signature that is being validated by
validating the hashed reference data in the SVT of the signature,
signing certificate chain, signed data and the signed bytes.
7.2. Aging algorithms
Even if the SVT provides protection against algorithms becoming
weakened or broken over time, this protection is only valid for as
long as the algorithms used to sign the SVT are still considered
secure. It is advisable to re-issue SVT in cases where an algorithm
protecting the SVT is getting close to its end of life.
One way to increase the resistance of algorithms becoming insecure,
is to issue multiple SVT for the same signature with different
algorithms and key lengths where one algorithm could still be secure
even if the corresponding algorithm used in the alternative SVT is
broken.
8. References
8.1. Normative References
[CADES] ETSI, "Electronic Signatures and Infrastructures (ESI);
CAdES digital signatures; Part 1: Building blocks and
CAdES baseline signatures", ETSI EN 319 122-1 v1.1.1,
April 2016.
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[ETSI319102-1]
ETSI, "ETSI - Electronic Signatures and Infrastructures
(ESI); Procedures for Creation and Validation of AdES
Digital Signatures; Part 1: Creation and Validation",
ETSI EN 319 102-1 v1.1.1, May 2016.
[ISOPDF2] ISO, "Document management -- Portable document format --
Part 2: PDF 2.0", ISO 32000-2, July 2017.
[PADES] ETSI, "Electronic Signatures and Infrastructures (ESI);
PAdES digital signatures; Part 1: Building blocks and
PAdES baseline signatures", ETSI EN 319 142-1 v1.1.1,
April 2016.
[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/info/rfc2119>.
[RFC3125] Ross, J., Pinkas, D., and N. Pope, "Electronic Signature
Policies", RFC 3125, DOI 10.17487/RFC3125, September 2001,
<https://www.rfc-editor.org/info/rfc3125>.
[RFC3161] Adams, C., Cain, P., Pinkas, D., and R. Zuccherato,
"Internet X.509 Public Key Infrastructure Time-Stamp
Protocol (TSP)", RFC 3161, DOI 10.17487/RFC3161, August
2001, <https://www.rfc-editor.org/info/rfc3161>.
[RFC3647] Chokhani, S., Ford, W., Sabett, R., Merrill, C., and S.
Wu, "Internet X.509 Public Key Infrastructure Certificate
Policy and Certification Practices Framework", RFC 3647,
DOI 10.17487/RFC3647, November 2003,
<https://www.rfc-editor.org/info/rfc3647>.
[RFC5035] Schaad, J., "Enhanced Security Services (ESS) Update:
Adding CertID Algorithm Agility", RFC 5035,
DOI 10.17487/RFC5035, August 2007,
<https://www.rfc-editor.org/info/rfc5035>.
[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/info/rfc5280>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/info/rfc5652>.
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[RFC6931] Eastlake 3rd, D., "Additional XML Security Uniform
Resource Identifiers (URIs)", RFC 6931,
DOI 10.17487/RFC6931, April 2013,
<https://www.rfc-editor.org/info/rfc6931>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
DOI 10.17487/RFC7518, May 2015,
<https://www.rfc-editor.org/info/rfc7518>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>.
[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/info/rfc8174>.
[XADES] ETSI, "Electronic Signatures and Infrastructures (ESI);
XAdES digital signatures; Part 1: Building blocks and
XAdES baseline signatures", ETSI EN 319 132-1 v1.1.1,
April 2016.
[XMLDSIG11]
Eastlake, D., Reagle, J., Solo, D., Hirsch, F., Nystrom,
M., Roessler, T., and K. Yiu, "XML Signature Syntax and
Processing Version 1.1", W3C Proposed Recommendation, 11
April 2013.
8.2. Informative References
[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
Definition Language (CDDL): A Notational Convention to
Express Concise Binary Object Representation (CBOR) and
JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
June 2019, <https://www.rfc-editor.org/info/rfc8610>.
Appendix A. Appendix: XML signature profile
This appendix defines a profile for implementing SVT with a signed
XML document, and defines the following aspects of SVT usage:
* How to include reference data related to XML signatures and XML
documents in an SVT.
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* How to add an SVT token to a XML signature.
XML documents can have any number of signature elements, signing an
arbitrary number of fragments of XML documents. The actual signature
element may be included in the signed XML document (enveloped),
include the signed data (enveloping) or may be separate from the
signed content (detached).
To provide a generic solution for any type of XML signature an SVT is
added to each XML signature element within the XML signature
<ds:Object> element.
A.1. Notation
A.1.1. References to XML Elements from XML Schemas
When referring to elements from the W3C XML Signature namespace
(http://www.w3.org/2000/09/xmldsig#) the following syntax is used:
* <ds:Signature>
When referring to elements from the ETSI XAdES XML Signature
namespace (http://uri.etsi.org/01903/v1.3.2#) the following syntax is
used:
* <xades:CertDigest>
When referring to elements defined in this specification
(http://id.swedenconnect.se/svt/1.0/sig-prop/ns) the following syntax
is used:
* <svt:Element>
A.2. SVT in XML Documents
When SVT is provided for XML signatures then one SVT MUST be provided
for each XML signature.
An SVT embedded within the XML signature element MUST be placed in a
<svt:SignatureValidationToken> element as defined in Appendix A.2.1.
A.2.1. SignatureValidationToken Signature Property
The <svt:SignatureValidationToken> element MUST be placed in a
<ds:SignatureProperty> element in accordance with [XMLDSIG11]. The
<ds:SignatureProperty> element MUST be placed inside a
<ds:SignatureProperties> element inside a <ds:Object> element inside
a <ds:Signature> element.
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Note: [XMLDSIG11] requires the Target attribute to be present in
<ds:SignatureProperty>, referencing the signature targeted by this
signature property. If an SVT is added to a signature that do not
have an Id attribute, implementations SHOULD add an Id attribute to
the <ds:Signature> element and reference that Id in the Target
attribute. This Id attribute and Target attribute value matching is
required by the [XMLDSIG11] standard, but it is redundant in the
context of SVT validation as the SVT already contains information
that uniquely identifies the target signature. Validation
applications SHOULD not reject an SVT token because of Id and Target
attribute mismatch, and MUST rely on matching against signature using
signed information in the SVT itself.
The <svt:SignatureValidationToken> element is defined by the
following XML Schema:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
targetNamespace="http://id.swedenconnect.se/svt/1.0/sig-prop/ns"
xmlns:svt="http://id.swedenconnect.se/svt/1.0/sig-prop/ns">
<xs:element name="SignatureValidationToken"
type="svt:SignatureValidationTokenType" />
<xs:complexType name="SignatureValidationTokenType">
<xs:simpleContent>
<xs:extension base="xs:string">
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:schema>
The SVT token MUST be included as a string representation of the SVT
JWT. Note that this is the string representation of the JWT without
further encoding. The SVT MUST NOT be represented by the Base64
encoded bytes of the JWT string.
Example:
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<ds:Signature Id="MySignatureId">
...
<ds:Object>
<ds:SignatureProperties>
<ds:SignatureProperty Target="#MySignatureId">
<svt:SignatureValidationToken>
eyJ0eXAiOiJKV1QiLCJhb...2aNZ
</svt:SignatureValidationToken>
</ds:SignatureProperty>
</ds:SignatureProperties>
</ds:Object>
</ds:Signature>
A.2.2. Multiple SVT in an XML signature
If a new SVT is stored in a signature which already contains a
previously issued SVT, implementations can choose to either replace
the existing SVT or to store the new SVT in addition to the existing
SVT.
If the new SVT is stored in addition to the old SVT, it SHOULD be
stored in a new <ds:SignatureProperty> element inside the existing
<ds:SignatureProperties> element where the old SVT is located.
For interoperability robustness, signature validation applications
MUST be able to handle signatures where the new SVT is located in a
new <ds:Object> element.
A.3. XML signature SVT Claims
A.3.1. XML Profile Identifier
When this profile is used the SigValidation object MUST contain a
"profile" claim with the value "XML".
A.3.2. XML Signature Reference Data
The SVT Signature object MUST contain a "sig_ref" claim (SigReference
object) with the following elements:
* "id" -- The Id-attribute of the XML signature, if present.
* "sig_hash" -- The hash over the signature value bytes.
* "sb_hash" -- The hash over the canonicalized <ds:SignedInfo>
element (the bytes the XML signature algorithm has signed to
generated the signature value).
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A.3.3. XML Signed Data Reference Data
The SVT Signature object MUST contain one instance of the "sig_data"
claim (SignedData object) for each <ds:Reference> element in the
<ds:SignedInfo> element. The "sig_data" claim MUST contain the
following elements:
* "ref" -- The value of the URI attribute of the corresponding
<ds:Reference> element.
* "hash" -- The hash of all bytes identified corresponding
<ds:Reference> element after applying all identified
canonicalization and transformation algorithms. These are the
same bytes that is hashed by the hash value in the
<ds:DigestValue> element inside the <ds:Reference> element.
A.3.4. XML Signer Certificate References
The SVT Signature object MUST contain a "signer_cert_ref" claim
(CertReference object). The "type" parameter of the
"signer_cert_ref" claim MUST be either "chain" or "chain_hash".
* The "chain" type MUST be used when signature validation was
performed using one or more certificates where some or all of the
certificates in the chain are not present in the target signature.
* The "chain_hash" type MUST be used when signature validation was
performed using one or more certificates where all of the
certificates are present in the target signature.
A.4. JOSE Header
A.4.1. SVT Signing Key Reference
The SVT JOSE header for XML signatures must contain one of the
following header parameters in accordance with [RFC7515], for storing
a reference to the public key used to verify the signature on the
SVT:
* "x5c" -- Holds an X.509 certificate [RFC5280] or a chain of
certificates. The certificate holding the public key that
verifies the signature on the SVT MUST be the first certificate in
the chain.
* "kid" -- A key identifier holding the Base64 encoded hash value of
the certificate that can verify the signature on the SVT. The
hash algorithm MUST be the same hash algorithm used when signing
the SVT as specified by the alg header parameter.
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Appendix B. Appendix: PDF signature profile
This appendix defines a profile for implementing SVT with a signed
PDF document, and defines the following aspects of SVT usage:
* How to include reference data related to PDF signatures and PDF
documents in an SVT.
* How to add an SVT token to a PDF document.
PDF document signatures are added as incremental updates to the
signed PDF document and signs all data of the PDF document up until
the current signature. When more than one signature is added to a
PDF document the previous signature is signed by the next signature
and can not be updated with additional data after this event.
To minimize the impact on PDF documents with multiple signatures and
to stay backwards compatible with PDF software that do not understand
SVT, PDF documents add one SVT token for all signatures of the PDF as
an extension to a document timestamp added to the signed PDF as an
incremental update. This SVT covers all signatures of the signed
PDF.
B.1. SVT in PDF Documents
The SVT for a signed PDF document MAY provide signature validation
information about any of the present signatures in the PDF. The SVT
MUST contain a separate "sig" claim (Signature object) for each
signature on the PDF that is covered by the SVT.
An SVT added to a signed PDF document MUST be added to a document
timestamp accordance with ISO 32000-2:2017 [ISOPDF2].
The document timestamp contains an [RFC3161] timestamp token
(TSTInfo) in EncapsulatedContentInfo of the CMS signature. The SVT
MUST be added to the timestamp token (TSTInfo) as an Extension object
as defined in Appendix B.1.1.
B.1.1. SVT Extension to Timestamp Tokens
The SVT extension is an Extension suitable to be included in TSTInfo
as defined by [RFC3161].
The SVT extension is identified by the Object Identifier (OID)
1.2.752.201.5.2
Editors note: This is the current used OID. Consider assigning an
IETF extension OID.
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This extension data (OCTET STRING) holds the bytes of SVT JWT,
represented as a UTF-8 encoded string.
This extension MUST NOT be marked critical.
Note: Extensions in timestamp tokens according to [RFC3161] are
imported from the definition of the X.509 certificate extensions
defined in [RFC5280].
B.2. PDF signature SVT Claims
B.2.1. PDF Profile Identifier
When this profile is used the SigValidation object MUST contain a
"profile" claim with the value "PDF".
B.2.2. PDF Signature Reference Data
The SVT Signature object MUST contain a "sig_ref" claim (SigReference
object) with the following elements:
* "id" -- Absent or a Null value.
* "sig_hash" -- The hash over the signature value bytes.
* "sb_hash" -- The hash over the DER encoded SignedAttributes in
SignerInfo.
B.2.3. PDF Signed Data Reference Data
The SVT Signature object MUST contain one instance of the "sig_data"
claim (SignedData object) with the following elements:
* "ref" -- The string representation of the ByteRange value of the
PDF signature dictionary of the target signature. This is a
sequence of integers separated by space where each integer pair
specifies the start index and length of a byte range.
* "hash" -- The hash of all bytes identified by the ByteRange value.
This is the concatenation of all byte ranges identified by the
ByteRange value.
B.2.4. PDF Signer Certificate References
The SVT Signature object MUST contain a "signer_cert_ref" claim
(CertReference object). The "type" parameter of the
"signer_cert_ref" claim MUST be either "chain" or "chain_hash".
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* The "chain" type MUST be used when signature validation was
performed using one or more certificates where some or all of the
certificates in the chain are not present in the target signature.
* The "chain_hash" type MUST be used when signature validation was
performed using one or more certificates where all of the
certificates are present in the target signature.
Note: The referenced signer certificate MUST match any certificates
referenced using ESSCertID or ESSCertIDv2 from [RFC5035].
B.3. JOSE Header
B.3.1. SVT Signing Key Reference
The SVT JOSE header must contain one of the following header
parameters in accordance with [RFC7515], for storing a reference to
the public key used to verify the signature on the SVT:
* "x5c" -- Holds an X.509 certificate [RFC5280] or a chain of
certificates. The certificate holding the public key that
verifies the signature on the SVT MUST be the first certificate in
the chain.
* "kid" -- A key identifier holding the Base64 encoded hash value of
the certificate that can verify the signature on the SVT. The
hash algorithm MUST be the same hash algorithm used when signing
the SVT as specified by the alg header parameter. The referenced
certificate SHOULD be the same certificate that was used to sign
the document timestamp that contains the SVT.
Appendix C. Appendix: JWS Profile
This appendix defines a profile for implementing SVT with a JWS
signed payload according to [RFC7515], and defines the following
aspects of SVT usage:
* How to include reference data related to JWS signatures in an SVT.
* How to add an SVT token to JWS signatures.
A JWS may have one or more signatures depending on its serialization
format, signing the same payload data. A JWS either contains the
data to be signed (enveloping) or may sign any externally associated
payload data (detached).
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To provide a generic solution for JWS, an SVT is added to each
present signature as a JWS Unprotected Header. If a JWS includes
multiple signatures, then each signature includes its own SVT.
C.1. SVT in JWS
An SVT token MAY be added to any signature of a JWS to support
validation of that signature. If more than one signature is present
then each present SVT MUST provide information exclusively related to
one associated signature and MUST NOT include information about any
other signature in the JWS.
Each SVT is stored in its associated signature's "svt" header as
defined in Appendix C.1.1.
C.1.1. "svt" Header Parameter
The "svt" (Signature Validation Token) Header Parameter is used to
contain an array of SVT tokens to support validation of the
associated signature. Each SVT token in the array has the format of
a JWT as defined in [RFC7519] and is stored using its natural string
representation without further wrapping or encoding.
The "svt" Header Parameter, when used, MUST be included as a JWS
Unprotected Header.
Note: JWS Unprotected Header is not supported with JWS Compact
Serialization. A consequence of adding an SVT token to a JWS is
therefore that JWS JSON Serialization MUST be used, either in the
form of general JWS JSON Serialization (for one or more signatures)
or in the form of flattened JWS JSON Serialization (optionally used
when only one signature is present in the JWS).
C.1.2. Multiple SVT in a JWS signature
If a new SVT is stored in a signature which already contains a
previously issued SVT, implementations can choose to either replace
the existing SVT or to store the new SVT in addition to the existing
SVT.
If a JWS signature already contains an array of SVTs and a new SVT is
to be added, then the new SVT MUST be added to the array of SVT
tokens in the existing "svt" Header Parameter.
C.2. JWS signature SVT Claims
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C.2.1. JWS Profile Identifier
When this profile is used the SigValidation object MUST contain a
"profile" claim with the value "JWS".
C.2.2. JWS Signature Reference Data
The SVT Signature object MUST contain a "sig_ref" claim (SigReference
object) with the following elements:
* "sig_hash" -- The hash over the associated signature value (the
bytes of the base64url-decoded signature parameter).
* "sb_hash" -- The hash over all bytes signed by the associated
signature (the JWS Signing Input according to [RFC7515]).
C.2.3. JWS Signed Data Reference Data
The SVT Signature object MUST contain one instance of the "sig_data"
claim (SignedData object) with the following elements:
* "ref" -- This parameter MUST hold one of the following thee
possible values.
1. The explicit string value "payload" if the signed JWS Payload
is embedded in a "payload" member of the JWS.
2. The explicit string value "detached" if the JWS signs detached
payload data without explicit reference.
3. A URI that can be used to identify or fetch the detached
signed data. The means to determine the URI for the detached
signed data is outside the scope of this specification.
* "hash" -- The hash over the JWS Payload data bytes (not its
base64url-encoded string representation).
C.2.4. JWS Signer Certificate References
The SVT Signature object MUST contain a "signer_cert_ref" claim
(CertReference object). The "type" parameter of the
"signer_cert_ref" claim MUST be either "chain" or "chain_hash".
* The "chain" type MUST be used when signature validation was
performed using one or more certificates where some or all of the
certificates in the chain are not present in the target signature.
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* The "chain_hash" type MUST be used when signature validation was
performed using one or more certificates where all of the
certificates are present in the target signature JOSE header using
the "x5c" Header Parameter.
C.3. SVT JOSE Header
C.3.1. SVT Signing Key Reference
The SVT JOSE header must contain one of the following header
parameters in accordance with [RFC7515], for storing a reference to
the public key used to verify the signature on the SVT:
* "x5c" -- Holds an X.509 certificate [RFC5280] or a chain of
certificates. The certificate holding the public key that
verifies the signature on the SVT MUST be the first certificate in
the chain.
* "kid" -- A key identifier holding the Base64 encoded hash value of
the certificate that can verify the signature on the SVT. The
hash algorithm MUST be the same hash algorithm used when signing
the SVT as specified by the alg header parameter.
Appendix D. Appendix: Schemas
D.1. Concise Data Definition Language (CDDL)
The following informative CDDL [RFC8610] express the structure of an
SVT token:
svt = {
jti: text
iss: text
iat: uint
? aud: text / [* text]
? exp: uint
sig_val_claims: SigValClaims
}
SigValClaims = {
ver: text
profile: text
hash_algo: text
sig: [+ Signature]
? ext: Extension
}
Signature = {
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sig_ref: SigReference
sig_data_ref: [+ SignedDataReference]
signer_cert_ref: CertReference
sig_val: [+ PolicyValidation]
? time_val: [* TimeValidation]
? ext: Extension
}
SigReference = {
? id: text / null
sig_hash: binary-value
sb_hash: binary-value
}
SignedDataReference = {
ref: text
hash: binary-value
}
CertReference = {
type: "chain" / "chain_hash"
ref: [+ text]
}
PolicyValidation = {
pol: text
res: "PASSED" / "FAILED" / "INDETERMINATE"
? msg: text / null
? ext: Extension
}
TimeValidation = {
"time": uint
type: text
iss: text
? id: text / null
? hash: binary-value / null
? val: [* PolicyValidation]
? ext: Extension
}
Extension = {
+ text => text
} / null
binary-value = text ; base64 classic with padding
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D.2. JSON Schema
The following informative JSON schema describes the syntax of the SVT
token payload.
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"title": "Signature Validation Token JSON Schema",
"description": "Schema defining the payload format for SVT",
"type": "object",
"required": [
"jti",
"iss",
"iat",
"sig_val_claims"
],
"properties": {
"jti": {
"description": "JWT ID",
"type": "string"
},
"iss": {
"description": "Issuer",
"type": "string"
},
"iat": {
"description": "Issued At",
"type": "integer"
},
"aud": {
"description": "Audience",
"type": [
"string",
"array"
],
"items": {"type": "string"}
},
"exp": {
"description": "Expiration time (seconds since epoch)",
"type": "integer"
},
"sig_val_claims": {
"description": "Signature validation claims",
"type": "object",
"required": [
"ver",
"profile",
"hash_algo",
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"sig"
],
"properties": {
"ver": {
"description": "Version",
"type": "string"
},
"profile": {
"description": "Implementation profile",
"type": "string"
},
"hash_algo": {
"description": "Hash algorithm URI",
"type": "string"
},
"sig": {
"description": "Validated signatures",
"type": "array",
"items": {
"$ref": "#/$def/Signature"
},
"minItems": 1
},
"ext": {
"description": "Extension map",
"$ref": "#/$def/Extension"
}
},
"additionalProperties": false
}
},
"additionalProperties": false,
"$def": {
"Signature":{
"type": "object",
"required": [
"sig_ref",
"sig_data_ref",
"signer_cert_ref",
"sig_val"
],
"properties": {
"sig_ref": {
"description": "Signature Reference",
"$ref": "#/$def/SigReference"
},
"sig_data_ref": {
"description": "Signed data array",
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"type": "array",
"items": {
"$ref" : "#/$def/SignedDataReference"
},
"minItems": 1
},
"signer_cert_ref": {
"description": "Signer certificate reference",
"$ref": "#/$def/CertReference"
},
"sig_val": {
"description": "Signature validation results",
"type": "array",
"items": {
"$ref": "#/$def/PolicyValidation"
},
"minItems": 1
},
"time_val": {
"description": "Time validations",
"type": "array",
"items": {
"$ref": "#/$def/TimeValidation"
}
},
"ext": {
"description": "Extension map",
"$ref": "#/$def/Extension"
}
},
"additionalProperties": false
},
"SigReference":{
"type": "object",
"required": [
"sig_hash",
"sb_hash"
],
"properties": {
"sig_hash": {
"description": "Hash of the signature value",
"type": "string",
"format": "base64"
},
"sb_hash": {
"description": "Hash of the Signed Bytes",
"type": "string",
"format": "base64"
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},
"id": {
"description": "Signature ID reference",
"type": ["string","null"]
}
},
"additionalProperties": false
},
"SignedDataReference": {
"type": "object",
"required": [
"ref",
"hash"
],
"properties": {
"ref": {
"description": "Reference to the signed data",
"type": "string"
},
"hash": {
"description": "Signed data hash",
"type": "string",
"format": "base64"
}
},
"additionalProperties": false
},
"CertReference":{
"type": "object",
"required": [
"type",
"ref"
],
"properties": {
"type": {
"description": "Type of certificate reference",
"type": "string",
"enum": ["chain","chain_hash"]
},
"ref": {
"description": "Certificate reference data",
"type": "array",
"items": {
"type": "string",
"format": "base64"
},
"minItems": 1
}
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},
"additionalProperties": false
},
"PolicyValidation":{
"type": "object",
"required": [
"pol",
"res"
],
"properties": {
"pol": {
"description": "Policy identifier",
"type": "string"
},
"res": {
"description": "Signature validation result",
"type": "string",
"enum": ["PASSED","FAILED","INDETERMINATE"]
},
"msg": {
"description": "Message",
"type": ["string","null"]
},
"ext": {
"description": "Extension map",
"$ref": "#/$def/Extension"
}
},
"additionalProperties": false
},
"TimeValidation":{
"type": "object",
"required": [
"time",
"type",
"iss"
],
"properties": {
"time": {
"description": "Verified time",
"type": "integer"
},
"type": {
"description": "Type of time validation proof",
"type": "string"
},
"iss": {
"description": "Issuer of the time proof",
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"type": "string"
},
"id": {
"description": "Time evidence identifier",
"type": ["string","null"]
},
"hash": {
"description": "Hash of time evidence",
"type": ["string","null"],
"format": "base64"
},
"val": {
"description": "Validation result",
"type": "array",
"items": {
"$ref": "#/$def/PolicyValidation"
}
},
"ext": {
"description": "Extension map",
"$ref": "#/$def/Extension"
}
},
"additionalProperties": false
},
"Extension": {
"description": "Extension map",
"type": ["object","null"],
"required": [],
"additionalProperties": {
"type": "string"
}
}
}
}
Appendix E. Appendix: Examples
The following example illustrates a basic SVT according to this
specification issued for a signed PDF document.
Note: Line breaks in the decoded example are inserted for
readablilty. Line breaks are not allowed in valid JSON data.
Signature validation token JWT:
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eyJraWQiOiJPZW5JKzQzNEpoYnZmRG50ZlZcLzhyT3hHN0ZrdnlqYUtWSmFWcUlG
QlhvaFZoQWU1Zks4YW5vdjFTNjg4cjdLYmFsK2Z2cGFIMWo4aWJnNTJRQnkxUFE9
PSIsInR5cCI6IkpXVCIsImFsZyI6IlJTNTEyIn0.eyJhdWQiOiJodHRwOlwvXC9l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.TdHCoIUSZj2zMINKg7E44-8VE_mJq6TG1OoPwnYSs_hyUbuX
mrLJpuk8GR5YrndeOucPUYAwPxHt_f68JIQyFTi0agO9VJjn1R7Pj3Jt6WG9pYVN
n5LH-D1maxD11ZxxbcYeHbsstd2Sy2uMa3BdpsstGdPymSmc6GxY5uJoL0-5vwo_
3l-4Bb3LCTiuxYPcmztKIbDy2hEgJ3Hx1K4HF0SHgn3InpqBev3hm2SLw3hH5BCM
rywBAhHYE6OGE0aOJ6ktA5UP0jIIHfaw9i1wIiJtHTaGuvtyWSLk5cshmun9Hkdk
kRTA75bzuq0Iyd0qh070rA8Gje-s4Tw4xzttgKx1KSkvy8n5FqvzWdsZvclCG2mY
Y9rMxh_7607NXcxajAP4yDOoKNs5nm937ULe0vCN8a7WTrFuiaGjry7HhzRM4C5A
qxbDOBXPLyoMr4qn4LRJCHxOeLZ6o3ugvDOOWsyjk3eliyBwDu8qJH7UmyicLxDc
Cr0hUK_kvREqjD2Z
Decoded JWT Header:
{
"kid":"OenI+434JhbvfDntfV\/8rOxG7FkvyjaKVJaVqIFBXohVhAe5fK8anov
1S688r7Kbal+fvpaH1j8ibg52QBy1PQ==",
"typ":"JWT",
"alg":"RS512"
}
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Decoded JWT Claims:
{
"aud" : "http://example.com/audience1",
"iss" : "https://swedenconnect.se/validator",
"iat" : 1603458421,
"jti" : "4d1396f1ff728f40d52403b61c574486",
"sig_val_claims" : {
"sig" : [ {
"ext" : null,
"sig_val" : [ {
"msg" : "OK",
"ext" : null,
"res" : "PASSED",
"pol" : "http://id.swedenconnect.se/svt/sigval-policy/
ts-pkix/01"
} ],
"sig_ref" : {
"sig_hash" : "ycePVLIzdcpK97IYOhFIf1ny79HmICbSVzIeZNbizo7rGIw
HNN0zXISyKGjCvnonOaQGfL/P3vDtB88yKSWeXg==",
"id" : "id-73989c6fc063636ab5e753f10f757467",
"sb_hash" : "BoPV4WCA9sAIahjK1HajfFxi+AzC4JGTuf39W3ZWjczDCURx
dc9YeteHtcxGVeggpxHJ75/cQ7HN1dDdliyIwg=="
},
"signer_cert_ref" : {
"ref" : [ "1+aaJetg7relERlUDYEiU4ZIZhT4RUviIQZuK7o1GFKaTPQ6y+
kx/PNtDrpuqQ6XfrkH9wYDK4ey0y4WrNErnw==",
"h4PDxb5ZKmx1eTSqvVvYG8g33s05JzwB+NgEHFU4gc9tqG0kgH
kf6W3oLzkTwwurIh6Y9AafZYqc2zP2pE2p4Q==",
"Dd2C5sB0IOQeMVnEBkM5Q9W96mBHNwwa2tzXMs+LwuYcOUvPkr
yGR0aPG8O9nIP3lbw6KjQ1hDmRk6zC8x2jdg==" ],
"type" : "chain_hash"
},
"sig_data_ref" : [ {
"ref" : "",
"hash" : "FcGpOOf8ilcPt21GDd2cGnLGDxRS5j7svM4app2H41dDELm2Czc
eTY02ndeJfWjintmQ376IlXTOAr31yzYzsg=="
}, {
"ref" : "#xades-11a155d92bf55774613bb7b661477cfd",
"hash" : "KRkgbZ6P/nhU63IMk0GiUfU/DTwveYiteQkwGeJqC5BzTNV8bQb
pedTTuWJPxqvJ0RY84hwm7eY/g0HrAOegKw=="
} ],
"time_val" : [ ]
} ],
"ext" : null,
"ver" : "1.0",
"profile" : "XML",
"hash_algo" : "http://www.w3.org/2001/04/xmlenc#sha512"
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}
}
Authors' Addresses
Stefan Santesson
IDsec Solutions AB
Forskningsbyn Ideon
SE-223 70 Lund
Sweden
Email: sts@aaa-sec.com
Russ Housley
Vigil Security, LLC
516 Dranesville Road
Herndon, VA, 20170
United States of America
Email: housley@vigilsec.com
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