Network Working Group R. Housley
Internet-Draft Vigil Security
Intended status: Standards Track 25 March 2025
Expires: 26 September 2025
An Attribute for Statement of Possession of a Private Key
draft-ietf-lamps-private-key-stmt-attr-02
Abstract
This document specifies an attribute for a statement of possession of
a private key by a certificate subject. As part of X.509 certificate
enrollment, a Certification Authority (CA) typically demands proof
that the subject possesses the private key that corresponds to the
to-be-certified public key. In some cases, a CA might accept a
signed statement from the certificate subject. For example, when a
certificate subject needs separate certificates for signature and key
establishment, a statement that can be validated with the previously
issued signature certificate for the same subject might be adequate
for subsequent issuance of the key establishment certificate.
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 26 September 2025.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. ASN.1 . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Attribute for Statement of Possession of a Private Key . . . 4
3. Conventions for PKCS#10 . . . . . . . . . . . . . . . . . . . 5
4. Conventions for CRMF . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 9
Appendix B. Example use of the privateKeyPossessionStatement
Attribute . . . . . . . . . . . . . . . . . . . . . . . . 10
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 19
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
This document specifies an attribute for a statement of possession of
a private key by a certificate subject. As part of X.509 certificate
[RFC5280] enrollment, a Certification Authority (CA) typically
demands proof that the subject possesses the private key that
corresponds to the to-be-certified public key. In some cases, a CA
might accept a signed statement from the certificate subject. For
example, when a certificate subject needs separate certificates for
signature and key establishment, a signed statement that can be
validated with the previously issued signature certificate for the
same subject might be adequate for subsequent issuance of the key
establishment certificate. Note that [RFC6955] offers some
algorithms to provide proof of possession for Diffie-Hellman private
keys. However, these algorithms are not suitable for use with
PKCS#10 [RFC2986]. On the other hand, the the attribute specified in
this document is suitable for use with PKCS#10 and the Certificate
Request Message Format (CRMF) [RFC4211].
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In many situations a subject needs two certificates, one for digiatal
signatures, and a separate one for key establishment. For example, a
subject may need a signature certificate that contains a ML-DSA
public key and a key establishment certificate that contains a ML-KEM
public key. For another example, a subject may need a signature
certificate that contains a ECDSA public key and a key establishment
certificate that contains a ECDH public key.
In this situation, a CA might accept a signed statement that can be
validated with the previously issued signature certificate as
adequate for subsequent issuance of the key establishment
certificate.
This document defines an attribute for a statement of possession,
which is used in lieu of the usual proof of possession mechanisms.
The statement is simply an assertion that the requestor of a key
establishment certificate has possession of the key establishment
private key. If the Certificate Policy [RFC3647] allows, the CA MAY
accept this statement in lieu of proof that the requestor has
possession of the private key.
When using the attribute defined in this document make a statement
about the possession of the key establishment private key, the
process for a subject to obtain two certificates is:
1. The subject generates the signature key pair.
2. The subject composes a PKCS#10 Certificate Signing Request (CSR)
in the usual manner. It includes a signature that is produced
with the private key from step 1.
3. The subject sends the CSR to the CA, and it gets back a signature
certificate. The signature certificate includes a key usage of
digitalSignature, nonRepudiation, or both Section 4.2.1.3 of
[RFC5280].
4. The subject generates the key establishment key pair.
5. The subject composes a PKCS#10 CSR containing the key
establishment public key. The CSR attributes include the
attribute specified in Section 2 of this document. The subject
name matches the one from step 3. The CSR includes a signature
that is produced with the private key from step 1.
6. The subject sends the CSR to the CA, and it gets back a key
establishment certificate. The key establishment certificate
includes a key usage of keyEncipherment or keyAgreement
Section 4.2.1.3 of [RFC5280].
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1.1. ASN.1
The attribute defined in this document is generated using ASN.1
[X680], using the Distinguished Encoding Rules (DER) [X690].
1.2. Terminology
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.
2. Attribute for Statement of Possession of a Private Key
The attribute for statement of possession of a private key is
included in a certificate request to make the following statement:
"The subject of the signature certificate that is used to validate
the signature on this certificate request states, without
providing proof, that it has possession of the private key that
corresponds to the public key in the certificate request."
The CA MUST perform certification path validation for the signature
certificate as specified in Section 6 of [RFC5280]. If the
certification path is not valid, then the CA MUST reject the
certificate request.
The CA MUST validate the signature on the certificate request using
the public key from the signature certificate. If the signature is
not valid, then the CA MUST reject the certificate request.
The subject in the signature certificate SHOULD be the same as the
subject name in the certificate request. If they are different, the
certificate policy MUST describe how the CA can determine that the
two subject names identify the same entity. If the CA is unable to
determine that the two subject names identify the same entity, then
the CA MUST reject the certificate request.
If subject alternative names are present in the certificate request,
they SHOULD match subject alternative names in the signature
certificate. If the CA is unable to determine that each of subject
alternative names identifies the same entity as is named in the
signature certificate, then the CA MUST reject the certificate
request.
The attribute for statement of possession of a private key has the
following structure:
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id-at-statementOfPossession OBJECT IDENTIFIER ::=
{ 1 3 6 1 4 1 22112 2 1 }
privateKeyPossessionStatement ATTRIBUTE ::= {
TYPE PrivateKeyPossessionStatement
IDENTIFIED BY id-at-statementOfPossession }
PrivateKeyPossessionStatement ::= SEQUENCE {
signer IssuerAndSerialNumber,
cert Certificate OPTIONAL }
The components of the PrivateKeyStatement SEQUENCE have the following
semantics:
signer: the issuer name and certificate serial number of the
signature certificate.
cert: the signature certificate. If the issuer of the key
establishment certificate will be the same as the issuer of the
signature certificate, then this component MAY be omitted.
When the signature certificate is omitted, the signer is
assuming that the CA has a mechanism to obtain all valid
certificates that it issued.
3. Conventions for PKCS#10
This section specifies the conventions for using the attribute for
statement of possession of a private key with PKCS#10 [RFC2986] when
requesting a key establishment certificate.
The PKCS#10 CertificationRequest always has three components, as
follows:
certificationRequestInfo: the subject name SHOULD be the same as
the subject name in the signature certificate, the
subjectPKInfo MUST contain the public key for the key
establishment algorithm, and the attributes MUST include
privateKeyPossessionStatement attribute as specified in
Section 2 of this document.
signatureAlgorithm: the signature algorithm MUST be one that can
be validated with the public key in the signature certificate.
signature: the signature over certificationRequestInfo MUST
validate with the public key in the signature certificate, and
certification path validation for the signature certificate
MUST be successful as specified in Section 6 of [RFC5280].
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4. Conventions for CRMF
This section specifies the conventions for using the attribute for
statement of possession of a private key with the CRMF [RFC4211] when
requesting a key establisment certificate.
The following ASN.1 types are defined for use with CRMF. They have
exactly the same semantics and syntax as the attribute discussed
above, but they offer a similar naming convention to the Registration
Controls in [RFC4211].
regCtrl-privateKeyPossessionStatement ATTRIBUTE ::=
privateKeyPossessionStatement
id-regCtrl-statementOfPossession OBJECT IDENTIFIER ::=
id-at-statementOfPossession
The CRMF CertificationRequest always has three components, as
follows:
certReq: the certTemplate MUST include the subject and the
publicKey components. The same subject name SHOULD match the
subject name in the signature certificate, and publicKey MUST
contain the public key for the key establishment algorithm.
popo: the ProofOfPossession MUST use the signature CHOICE, the
poposkInput MUST be present, POPOSigningKeyInput.authInfo MUST
use the sender CHOICE, the sender SHOULD be set to the subject
name that appears in the signature certificate, the publicKey
MUST contain a copy of the public key from the certTemplate,
the algorithmIdentifier MUST identify a signture algorithm that
can be validated with the public key in the signature
certificate, signature over the poposkInput MUST validate with
the public key in the signature certificate, and certification
path validation for the signature certificate MUST be
successful as specified in Section 6 of [RFC5280].
regInfo: the attributes MUST include
privateKeyPossessionStatement attribute as specified in
Section 2 of this document.
5. Security Considerations
The privateKeyPossessionStatement attribute MUST NOT be used to
obtain a signature certificate. Performing proof of possession of
the the signature private key is easily accomplished by signing the
certificate request.
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The subject is signing privateKeyPossessionStatement attribute to
tell the CA that it has possession of the key establishment private
key. This is being done instead of providing technical proof of
possession. If the subject has lost control of the signature private
key, then the signed privateKeyPossessionStatement attribute could be
generated by some other party. Timely revocation of the compromised
signature certificate is the only protection against such loss of
control.
If the CA revokes a compromised signature certificate, then the CA
SHOULD also revoke all key establishment certificates that were
obtained with privateKeyPossessionStatement attributes signed by that
compromised signature certificate.
The signature key pair and the key establishment key pair are
expected to have roughly the same security strength. To ensure that
the signature on the statement is not the weakest part of the
certificate enrollment, the signature key pair SHOULD be at least as
strong as the key establishment key pair.
If a CA allows subject in the key establishment certificate to be
different than the subject name in the signature certificate, then
certificate policy MUST describe how to determine that the two
subject names identify the same entity. Likewise, if a CA allows
subject alternative names in the key establishment certificate that
are not present in the signature certificate, then certificate policy
MUST describe how to determine that the subject alternative names
identify the same entity as is named in the signature certificate.
6. IANA Considerations
For the ASN.1 Module in the Appendix A of this document, IANA is
requested to assign an object identifier (OID) for the module
identifier (TBD0) with a Description of "d-mod-private-key-
possession-stmt-2025". The OID for the module should be allocated in
the "SMI Security for PKIX Module Identifier" registry
(1.3.6.1.5.5.7.0).
7. References
7.1. Normative References
[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>.
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[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986,
DOI 10.17487/RFC2986, November 2000,
<https://www.rfc-editor.org/rfc/rfc2986>.
[RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure
Certificate Request Message Format (CRMF)", RFC 4211,
DOI 10.17487/RFC4211, September 2005,
<https://www.rfc-editor.org/rfc/rfc4211>.
[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>.
[RFC5912] Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
DOI 10.17487/RFC5912, June 2010,
<https://www.rfc-editor.org/rfc/rfc5912>.
[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>.
[X680] ITU-T, "Information technology -- Abstract Syntax Notation
One (ASN.1): Specification of basic notation", ITU-T
Recommendation X.680, ISO/IEC 8824-1:2021, February 2021,
<https://www.itu.int/rec/T-REC-X.680>.
[X690] ITU-T, "Information technology -- ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER), Canonical
Encoding Rules (CER) and Distinguished Encoding Rules
(DER)", ITU-T Recommendation X.690, ISO/IEC 8825-1-2021,
February 2021, <https://www.itu.int/rec/T-REC-X.690>.
7.2. Informative References
[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/rfc/rfc3647>.
[RFC6955] Schaad, J. and H. Prafullchandra, "Diffie-Hellman Proof-
of-Possession Algorithms", RFC 6955, DOI 10.17487/RFC6955,
May 2013, <https://www.rfc-editor.org/rfc/rfc6955>.
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Appendix A. ASN.1 Module
This ASN.1 Module builds upon the conventions established in
[RFC5912].
<CODE STARTS>
PrivateKeyPossessionStatement-2025
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-private-key-possession-stmt-2025(TBD0) }
DEFINITIONS IMPLICIT TAGS ::= BEGIN
EXPORTS ALL;
IMPORTS
ATTRIBUTE
FROM PKIX-CommonTypes-2009 -- in [RFC5912]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkixCommon-02(57) }
Certificate
FROM PKIX1Explicit-2009 -- in [RFC5912]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkix1-explicit-02(51) }
IssuerAndSerialNumber
FROM CryptographicMessageSyntax-2010 -- [RFC6268]
{ iso(1) member-body(2) us(840) rsadsi(113549)
pkcs(1) pkcs-9(9) smime(16) modules(0)
id-mod-cms-2009(58) } ;
--
-- Private Key Possession Statement Attribute
--
id-at-statementOfPossession OBJECT IDENTIFIER ::=
{ 1 3 6 1 4 1 22112 2 1 }
privateKeyPossessionStatement ATTRIBUTE ::= {
TYPE PrivateKeyPossessionStatement
IDENTIFIED BY id-at-statementOfPossession }
PrivateKeyPossessionStatement ::= SEQUENCE {
signer IssuerAndSerialNumber,
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cert Certificate OPTIONAL }
--
-- Registration Control Support
--
RegControlSet ATTRIBUTE ::=
{ regCtrl-privateKeyPossessionStatement, ... }
regCtrl-privateKeyPossessionStatement ATTRIBUTE ::=
privateKeyPossessionStatement
id-regCtrl-statementOfPossession OBJECT IDENTIFIER ::=
id-at-statementOfPossession
END
<CODE ENDS>
Appendix B. Example use of the privateKeyPossessionStatement Attribute
In this example, the self-signed certificate for the CA is:
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
Alice generates her ECDSA signature key pair. Then, Alice composes a
PKCS#10 Certificate Signing Request (CSR) in the usual manner as
specified in [RFC2986]. The CSR includes a signature that is
produced with her ECDSA private key. The CSR is:
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-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----
The CA issues a signature certificate to Alice:
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
Alice generates her ECDH key establishment key pair. Then, Alice
composes a PKCS#10 CSR. The CSR attributes include the
privateKeyPossessionStatement attribute, which points to her ECDSA
signature certificate. The CSR includes her ECDH public key and a
signature that is produced with her ECDSA private key. The CSR is:
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-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----
The CSR decodes to:
0 1073: SEQUENCE {
4 952: SEQUENCE {
8 1: INTEGER 0
11 60: SEQUENCE {
13 11: SET {
15 9: SEQUENCE {
17 3: OBJECT IDENTIFIER countryName (2 5 4 6)
22 2: PrintableString 'US'
: }
: }
26 11: SET {
28 9: SEQUENCE {
30 3: OBJECT IDENTIFIER stateOrProvinceName (2 5 4 8)
35 2: PrintableString 'VA'
: }
: }
39 16: SET {
41 14: SEQUENCE {
43 3: OBJECT IDENTIFIER localityName (2 5 4 7)
48 7: PrintableString 'Herndon'
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: }
: }
57 14: SET {
59 12: SEQUENCE {
61 3: OBJECT IDENTIFIER commonName (2 5 4 3)
66 5: PrintableString 'Alice'
: }
: }
: }
73 116: SEQUENCE {
75 14: SEQUENCE {
77 5: OBJECT IDENTIFIER ECDH (1 3 132 1 12)
84 5: OBJECT IDENTIFIER secp384r1 (1 3 132 0 34)
: }
91 98: BIT STRING
: 04 01 47 24 13 1F E7 2A D6 CE 45 F7 8B 85 A8 57
: BB 97 52 EA 19 D1 02 F1 39 BE 7B 95 58 04 27 CA
: 00 2F 0C 27 24 90 32 3D 46 8B 11 04 5C BF B5 5A
: 3B 60 DB 75 EF 9C 9A 2E 08 3A 31 4A 90 C2 48 CA
: 9F DE 4B E9 E7 E9 DA 33 7E EE C5 AD D9 62 00 FA
: 0C F6 37 99 EE 44 66 FC 99 3E F4 91 25 31 65 FC
: 16
: }
191 765: [0] {
195 103: SEQUENCE {
197 9: OBJECT IDENTIFIER
: extensionRequest (1 2 840 113549 1 9 14)
208 90: SET {
210 88: SEQUENCE {
212 12: SEQUENCE {
214 3: OBJECT IDENTIFIER
: basicConstraints (2 5 29 19)
219 1: BOOLEAN TRUE
222 2: OCTET STRING, encapsulates {
224 0: SEQUENCE {}
: }
: }
226 11: SEQUENCE {
228 3: OBJECT IDENTIFIER keyUsage (2 5 29 15)
233 4: OCTET STRING, encapsulates {
235 2: BIT STRING 3 unused bits
: '10000'B (bit 4)
: }
: }
239 34: SEQUENCE {
241 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17)
246 27: OCTET STRING, encapsulates {
248 25: SEQUENCE {
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250 23: [1] 'alice@email.example.com'
: }
: }
: }
275 23: SEQUENCE {
277 3: OBJECT IDENTIFIER
: certificatePolicies (2 5 29 32)
282 16: OCTET STRING, encapsulates {
284 14: SEQUENCE {
286 12: SEQUENCE {
288 10: OBJECT IDENTIFIER
: testCertPolicy (2 16 840 1 101 3 2 1 48 48)
: }
: }
: }
: }
: }
: }
: }
300 656: SEQUENCE {
304 10: OBJECT IDENTIFIER
: statementOfPossession (1 3 6 1 4 1 22112 2 1)
316 640: SET {
320 636: SEQUENCE {
324 79: SEQUENCE {
326 55: SEQUENCE {
328 11: SET {
330 9: SEQUENCE {
332 3: OBJECT IDENTIFIER countryName (2 5 4 6)
337 2: PrintableString 'US'
: }
: }
341 19: SET {
343 17: SEQUENCE {
345 3: OBJECT IDENTIFIER
: organizationName (2 5 4 10)
350 10: PrintableString 'Example CA'
: }
: }
362 19: SET {
364 17: SEQUENCE {
366 3: OBJECT IDENTIFIER commonName (2 5 4 3)
371 10: PrintableString 'ca.example'
: }
: }
: }
383 20: INTEGER
: 7F 74 A3 FC 03 6C E2 14 78 5C 59 61 4E 6F 8D F2
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: 4C 47 A8 79
: }
405 551: SEQUENCE {
409 430: SEQUENCE {
413 3: [0] {
415 1: INTEGER 2
: }
418 20: INTEGER
: 7F 74 A3 FC 03 6C E2 14 78 5C 59 61 4E 6F 8D F2
: 4C 47 A8 79
440 10: SEQUENCE {
442 8: OBJECT IDENTIFIER
: ecdsaWithSHA384 (1 2 840 10045 4 3 3)
: }
452 55: SEQUENCE {
454 11: SET {
456 9: SEQUENCE {
458 3: OBJECT IDENTIFIER
: countryName (2 5 4 6)
463 2: PrintableString 'US'
: }
: }
467 19: SET {
469 17: SEQUENCE {
471 3: OBJECT IDENTIFIER
: organizationName (2 5 4 10)
476 10: PrintableString 'Example CA'
: }
: }
488 19: SET {
490 17: SEQUENCE {
492 3: OBJECT IDENTIFIER
: commonName (2 5 4 3)
497 10: PrintableString 'ca.example'
: }
: }
: }
509 30: SEQUENCE {
511 13: UTCTime 09/01/2025 17:03:48 GMT
526 13: UTCTime 09/01/2026 17:03:48 GMT
: }
541 60: SEQUENCE {
543 11: SET {
545 9: SEQUENCE {
547 3: OBJECT IDENTIFIER
: countryName (2 5 4 6)
552 2: PrintableString 'US'
: }
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: }
556 11: SET {
558 9: SEQUENCE {
560 3: OBJECT IDENTIFIER
: stateOrProvinceName (2 5 4 8)
565 2: PrintableString 'VA'
: }
: }
569 16: SET {
571 14: SEQUENCE {
573 3: OBJECT IDENTIFIER
: localityName (2 5 4 7)
578 7: PrintableString 'Herndon'
: }
: }
587 14: SET {
589 12: SEQUENCE {
591 3: OBJECT IDENTIFIER
: commonName (2 5 4 3)
596 5: PrintableString 'Alice'
: }
: }
: }
603 118: SEQUENCE {
605 16: SEQUENCE {
607 7: OBJECT IDENTIFIER
: ecPublicKey (1 2 840 10045 2 1)
616 5: OBJECT IDENTIFIER
: secp384r1 (1 3 132 0 34)
: }
623 98: BIT STRING
: 04 80 1C FB A9 57 37 53 08 33 FF 36 41 E5 8D 6F
: 9E 47 D3 3A FE 95 58 16 55 E1 74 6D FE 23 CF 10
: 9B E4 C0 A3 55 A3 34 78 51 2F 72 35 CC 57 9A 78
: 93 3A A2 25 31 C2 D1 5D 89 02 8A 98 31 7F C3 30
: 52 1C C1 9E F1 3F DB 90 77 D7 A9 E8 A6 7E 45 7B
: AD DB 5D 4B F3 E5 B5 40 8D 50 25 20 CD C4 03 51
: B1
: }
723 118: [3] {
725 116: SEQUENCE {
727 12: SEQUENCE {
729 3: OBJECT IDENTIFIER
: basicConstraints (2 5 29 19)
734 1: BOOLEAN TRUE
737 2: OCTET STRING, encapsulates {
739 0: SEQUENCE {}
: }
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: }
741 11: SEQUENCE {
743 3: OBJECT IDENTIFIER
: keyUsage (2 5 29 15)
748 4: OCTET STRING, encapsulates {
750 2: BIT STRING 7 unused bits
: '1'B (bit 0)
: }
: }
754 29: SEQUENCE {
756 3: OBJECT IDENTIFIER
: subjectKeyIdentifier (2 5 29 14)
761 22: OCTET STRING, encapsulates {
763 20: OCTET STRING
: 23 1D 00 D1 FE ED 0B 39 10 11 98 18 CC 7D CD 70
: CD 8B D3 92
: }
: }
785 31: SEQUENCE {
787 3: OBJECT IDENTIFIER
: authorityKeyIdentifier (2 5 29 35)
792 24: OCTET STRING, encapsulates {
794 22: SEQUENCE {
796 20: [0]
: 3E 98 BC B2 EF DC 34 1B BE 71 92 D2 A3 FA 6D BC
: F2 66 40 AA
: }
: }
: }
818 23: SEQUENCE {
820 3: OBJECT IDENTIFIER
: certificatePolicies (2 5 29 32)
825 16: OCTET STRING, encapsulates {
827 14: SEQUENCE {
829 12: SEQUENCE {
831 10: OBJECT IDENTIFIER
: testCertPolicy (2 16 840 1 101 3 2 1 48 48)
: }
: }
: }
: }
: }
: }
: }
843 10: SEQUENCE {
845 8: OBJECT IDENTIFIER
: ecdsaWithSHA384 (1 2 840 10045 4 3 3)
: }
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855 103: BIT STRING, encapsulates {
858 100: SEQUENCE {
860 48: INTEGER
: 6B BF 53 2A 5D EC 16 95 9D 48 C1 DF A5 2D 5F D9
: B9 66 63 E2 EF CC B9 D5 10 3C 5A 16 CE BF 42 90
: 56 B7 18 B6 3E 2A 39 D8 8C 54 A0 5C A1 57 1E C8
910 48: INTEGER
: 44 9E 94 F7 5D 38 F0 D0 1B DE 78 9C 1D CA C6 15
: FD 54 62 B8 5B 0E 5C AD 2B 8B 42 6B 91 C1 C4 3F
: EA 02 0C B8 FD E5 33 03 93 59 C1 56 8B 2B BF 2E
: }
: }
: }
: }
: }
: }
: }
: }
960 10: SEQUENCE {
962 8: OBJECT IDENTIFIER ecdsaWithSHA384 (1 2 840 10045 4 3 3)
: }
972 103: BIT STRING, encapsulates {
975 100: SEQUENCE {
977 47: INTEGER
: 64 CD 1C F5 0B 59 C0 92 D8 3A 99 08 28 90 79 2C
: 31 D8 93 CB 30 8D 78 56 2F 7B ED BC F2 AC 89 AA
: E6 9D 07 DC 17 A5 E9 F0 12 F0 19 D0 D3 45 8D
1026 49: INTEGER
: 00 84 70 C0 95 C6 D1 B8 78 6A 75 6E A6 3A 00 DD
: E6 45 84 18 6A A0 8B 12 2E BC 41 1C 7D 56 E7 34
: 21 32 10 4E 27 D2 64 3D F4 F1 D4 46 75 E8 1F 0A
: 85
: }
: }
: }
The CA issues a key establishment certificate to Alice:
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-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
Acknowledgements
Thanks to Sean Turner, Joe Mandel, Mike StJohns, Mike Ounsworth, John
Gray, Carl Wallace, Corey Bonnell, and Hani Ezzadeen for their
constructive comments.
Author's Address
Russ Housley
Vigil Security, LLC
Herndon, VA,
United States of America
Email: housley@vigilsec.com
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