Internet DRAFT - draft-raza-ace-cbor-certificates
draft-raza-ace-cbor-certificates
ACE Working Group S. Raza
Internet-Draft J. Hoeglund
Intended status: Standards Track RISE AB
Expires: September 10, 2020 G. Selander
J. Mattsson
Ericsson AB
M. Furuhed
Nexus Group
March 09, 2020
CBOR Profile of X.509 Certificates
draft-raza-ace-cbor-certificates-04
Abstract
This document specifies a CBOR encoding and profiling of X.509 public
key certificate suitable for Internet of Things (IoT) deployments.
The full X.509 public key certificate format and commonly used ASN.1
DER encoding is overly verbose for constrained IoT environments.
Profiling together with CBOR encoding reduces the certificate size
significantly with associated known performance benefits.
The CBOR certificates are compatible with the existing X.509
standard, enabling the use of profiled and compressed X.509
certificates without modifications in the existing X.509 standard.
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
Task Force (IETF). Note that other groups may also distribute
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 10, 2020.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. CBOR Encoding . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Deployment settings . . . . . . . . . . . . . . . . . . . . . 6
5. Expected Certificate Sizes . . . . . . . . . . . . . . . . . 7
6. Native CBOR Certificates . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 8
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9.1. CBOR Certificate Types Registry . . . . . . . . . . . . . 8
9.2. CBOR Certificate Signature Algorithms Registry . . . . . 9
9.3. CBOR Certificate Public Key Algorithms Registry . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
10.1. Normative References . . . . . . . . . . . . . . . . . . 10
10.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Example CBOR Certificates . . . . . . . . . . . . . 12
A.1. Example X.509 Certificate . . . . . . . . . . . . . . . . 12
A.2. Example CBOR Certificate Compression . . . . . . . . . . 13
A.3. Example Native CBOR Certificate . . . . . . . . . . . . . 13
Appendix B. X.509 Certificate Profile, ASN.1 . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
One of the challenges with deploying a Public Key Infrastructure
(PKI) for the Internet of Things (IoT) is the size and encoding of
X.509 public key certificates [RFC5280], since those are not
optimized for constrained environments [RFC7228]. More compact
certificate representations are desirable. Due to the current PKI
usage of X.509 certificates, keeping X.509 compatibility is necessary
at least for a transition period. However, the use of a more compact
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encoding with the Concise Binary Object Representation (CBOR)
[RFC7049] reduces the certificate size significantly which has known
performance benefits in terms of decreased communication overhead,
power consumption, latency, storage, etc.
CBOR is a data format designed for small code size and small message
size. CBOR builds on the JSON data model but extends it by e.g.
encoding binary data directly without base64 conversion. In addition
to the binary CBOR encoding, CBOR also has a diagnostic notation that
is readable and editable by humans. The Concise Data Definition
Language (CDDL) [RFC8610] provides a way to express structures for
protocol messages and APIs that use CBOR. [RFC8610] also extends the
diagnostic notation.
CBOR data items are encoded to or decoded from byte strings using a
type-length-value encoding scheme, where the three highest order bits
of the initial byte contain information about the major type. CBOR
supports several different types of data items, in addition to
integers (int, uint), simple values (e.g. null), byte strings (bstr),
and text strings (tstr), CBOR also supports arrays [] of data items,
maps {} of pairs of data items, and sequences of data items. For a
complete specification and examples, see [RFC7049], [RFC8610], and
[I-D.ietf-cbor-sequence].
This document specifies the CBOR certificate profile, which is a CBOR
based encoding and compression of the X.509 certificate format. The
profile is based on previous work on profiling of X.509 certificates
for Internet of Things deployments [RFC7925] [X.509-IoT] which
retains backwards compatibility with X.509, and can be applied for
lightweight certificate based authentication with e.g. TLS
[RFC8446], DTLS [I-D.ietf-tls-dtls13], or EDHOC
[I-D.selander-ace-cose-ecdhe]. The same profile can be used for
"native" CBOR encoded certificates, which further optimizes the
performance in constrained environments but are not backwards
compatible with X.509, see Section 6.
Other work has looked at reducing size of X.509 certificates. The
purpose of this document is to stimulate a discussion on CBOR based
certificates.
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.
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This specification makes use of the terminology in [RFC7228].
3. CBOR Encoding
This section specifies the content and encoding for CBOR
certificates. The CBOR certificate can be a native CBOR certificate,
in which case the signature is calculated on the CBOR encoded data,
or a CBOR compressed X.509 certificates in which case the signature
is calculated on the DER encoded ASN.1 data in the X.509 certificate.
In both cases the certificate content is adhering to the restrictions
given by [RFC7925]. The corresponding ASN.1 schema is given in
Appendix A.
The encoding and compression has several components including: ASN.1
DER and base64 encoding are replaced with CBOR encoding, static
fields are elided, and elliptic curve points are compressed. The
X.509 fields and there CBOR encodings are listed below. Combining
these different components reduces the certificate size
significantly, something that is not possible with general purpose
compressions algorithms, see Figure 1.
CBOR certificates are defined in terms of RFC 7925 profiled X.509
certificates:
o version. The 'version' field is known (fixed to v3), and is
omitted in the CBOR encoding.
o serialNumber. The 'serialNumber' field is encoded as a CBOR byte
string.
o signature. The 'signature' field is always the same as the
'signatureAlgorithm' field and always omitted from the CBOR
encoding.
o issuer. In the general case, the Distinguished Name is encoded as
CBOR map, but if only CN is present the value can be encoded as a
single text value.
o validity. The 'notBefore' and 'notAfter' UTCTime fields are
encoded as as UnixTime in unsigned integer format.
o subject. The 'subject' field is restricted to specifying the
value of the common name. By RFC 7925 an IoT subject is
identified by either an EUI-64 for clients, or by a FQDN for
servers. An EUI-64 mapped from a 48-bit MAC address is encoded as
a CBOR byte string of length 6. Other EUI-64 is ncoded as a CBOR
byte string of length 8. A FQDN is encoded as a CBOR text string.
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o subjectPublicKeyInfo. If the 'algorithm' field is the default
(id-ecPublicKey and prime256v1), it is omitted in the CBOR
encoding., otherwise it is included in the
subjectPublicKeyInfo_algorithm field encoded as a int, (see
Section 9). The 'subjectPublicKey' is encoded as as a CBOR byte
string. Public keys of type id-ecPublicKey are point compressed
as defined in Section 2.3.3 of [SECG].
o extensions. The 'extensions' field is encoded as a CBOR array
where each extension is represented with an int. The extensions
mandated to be supported by RFC 7925 is encodeded as specified
below, where a critical extensions are encoded with a negative
sign.
I.e. non-critical keyUsage keyAgreement is encoded as 5, critical
basicConstraints cA is encodes as -3, and non-criticical
extKeyUsage id-kp-codeSigning + id-kp-OCSPSigning is encoded as
22.
If subjectAltName is present, the value is placed at the end of
the array encoded as a byte or text string following the encoding
rules for the subject field. If the array contains a single int,
extensions is encoded as the int instead of an array.
subjectAltName = 1
basicConstraints = 2 + cA
keyUsage = 3 + digitalSignature
+ 2 * keyAgreement + 4 * keyCertSign
extKeyUsage = 10 + id-kp-serverAuth + 2 * id-kp-clientAuth
+ 4 * id-kp-codeSigning + 8 * id-kp-OCSPSigning
o signatureAlgorithm. If the 'signatureAlgorithm' field is the
default (ecdsa-with-SHA256) it is omitted in the CBOR encoding,
otherwise it is included in the signatureAlgorithm field encoded
as an CBOR int (see Section 9).
o signatureValue. Since the signature algorithm and resulting
signature length are known, padding and extra length fields which
are present in the ASN.1 encoding are omitted and the
'signatureValue' field is encoded as a CBOR byte string. For
native CBOR certificates the signatureValue is calculated over the
certificate CBOR sequence excluding the signatureValue.
In addition to the above fields present in X.509, the CBOR ecoding
introduces an additional field
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o type. A CBOR int used to indicate the type of CBOR certificate.
Currently type can be a native CBOR certificate (type = 0) or a
CBOR compressed X.509 certificates (type = 1), see Section 9.
The Concise Data Definition Language (CDDL) for CBOR certificate is:
certificate = (
type : int,
serialNumber : bytes,
issuer : { + int => bytes } / text,
validity_notBefore: uint,
validity_notAfter: uint,
subject : text / bytes
subjectPublicKey : bytes
extensions : [ *4 int, ? text / bytes ] / int,
signatureValue : bytes,
? ( signatureAlgorithm : int,
subjectPublicKeyInfo_algorithm : int )
)
The signatureValue for native CBOR certificates is calculated over
the CBOR sequence:
(
type : int,
serialNumber : bytes,
issuer : { + int => bytes } / text,
validity_notBefore: uint,
validity_notAfter: uint,
subject : text / bytes
subjectPublicKey : bytes
extensions : [ *4 int, ? text / bytes ] / int,
? ( signatureAlgorithm : int,
subjectPublicKeyInfo_algorithm : int )
)
TODO - Specify exactly how issuer is encoded into a map / text and
back again.
4. Deployment settings
CBOR certificates can be deployed with legacy X.509 certificates and
CA infrastructure. In order to verify the signature, the CBOR
certificate is used to recreate the original X.509 data structure to
be able to verify the signature.
For the currently used DTLS v1.2 protocol, where the handshake is
sent unencrypted, the actual encoding and compression can be done at
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different locations depending on the deployment setting. For
example, the mapping between CBOR certificate and standard X.509
certificate can take place in a 6LoWPAN border gateway which allows
the server side to stay unmodified. This case gives the advantage of
the low overhead of a CBOR certificate over a constrained wireless
links. The conversion to X.509 within an IoT device will incur a
computational overhead, however, this is negligible compared to the
reduced communication overhead.
For the setting with constrained server and server-only
authentication, the server only needs to be provisioned with the CBOR
certificate and does not perform the conversion to X.509. This
option is viable when client authentication can be asserted by other
means.
For DTLS v1.3, because certificates are encrypted, the proposed
encoding needs to be done fully end-to-end, through adding the
encoding/decoding functionality to the server. This corresponds to
the proposed native mode, a new certificate compression scheme. The
required changes on the server side are in line with recent protocols
utilizing cbor encoding for communication with resource constrained
devices [RFC8613].
5. Expected Certificate Sizes
The CBOR encoding of the sample certificate given in Appendix A
results in the numbers shown in Figure 1. After RFC 7925 profiling,
most duplicated information has been removed, and the remaining text
strings are minimal in size. Therefore the further size reduction
reached with general compression mechanisms will be small, mainly
corresponding to making the ASN.1 endcoding more compact. The zlib
number was calculated with zlib-flate.
zlib-flate -compress < cert.der > cert.compressed
+------------------+--------------+------------+--------------------+
| | RFC 7925 | zlib | CBOR Certificate |
+------------------+---------------------------+--------------------+
| Certificate Size | 314 | 295 | 136 |
+------------------+--------------+------------+--------------------+
Figure 1: Comparing Sizes of Certificates (bytes)
6. Native CBOR Certificates
Further performance improvements can be achieved with the use of
native CBOR certificates. In this case the signature is calculated
over the CBOR encoded structure rather than the ASN.1 encoded
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structure. This removes entirely the need for ASN.1 and reduces the
processing in the authenticating devices.
This solution applies when the devices are only required to
authenticate with a set of native CBOR certificate compatible
servers, which may become a preferred approach for future
deployments. The mapping between X.509 and CBOR certificates enables
a migration path between the backwards compatible format and the
fully optimized format. This motivates introducing a type flag to
indicate if the certificate should be restored to X.509 or kept cbor
encoded.
7. Security Considerations
The CBOR profiling of X.509 certificates does not change the security
assumptions needed when deploying standard X.509 certificates but
decreases the number of fields transmitted, which reduces the risk
for implementation errors.
Conversion between the certificate formats can be made in constant
time to reduce risk of information leakage through side channels.
The current version of the format hardcodes the signature algorithm
which does not allow for crypto agility. A COSE crypto algorithm can
be specified with small overhead, and this changed is proposed for a
future version of the draft.
8. Privacy Considerations
The mechanism in this draft does not reveal any additional
information compared to X.509.
Because of difference in size, it will be possible to detect that
this profile is used.
The gateway solution described in Section 4 requires unencrypted
certificates.
9. IANA Considerations
9.1. CBOR Certificate Types Registry
IANA has created a new registry titled "CBOR Certificate Types" under
the new heading "CBOR Certificate". The registration procedure is
"Expert Review". The columns of the registry are Value, Description,
and Reference, where Value is an integer and the other columns are
text strings. The initial contents of the registry are:
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+-------+---------------------------------------+-------------------+
| Value | Description | Reference |
+-------+---------------------------------------+-------------------+
| 0 | Native CBOR Certificate. | [[this document]] |
| 1 | CBOR Compressed X.509 Certificate | [[this document]] |
+-------+---------------------------------------+-------------------+
Figure 2: CBOR Certificate Types
9.2. CBOR Certificate Signature Algorithms Registry
IANA has created a new registry titled "CBOR Certificate Signature
Algorithms" under the new heading "CBOR Certificate". The
registration procedure is "Expert Review". The columns of the
registry are Value, X.509 Algorithm, and Reference, where Value is an
integer and the other columns are text strings. The initial contents
of the registry are:
+-------+---------------------------------------+-------------------+
| Value | X.509 Signature Algorithm | Reference |
+-------+---------------------------------------+-------------------+
| 0 | ecdsa-with-SHA384 | [[this document]] |
| 1 | ecdsa-with-SHA512 | [[this document]] |
| 2 | id-ecdsa-with-shake128 | [[this document]] |
| 3 | id-ecdsa-with-shake256 | [[this document]] |
| 4 | id-Ed25519 | [[this document]] |
| 5 | id-Ed448 | [[this document]] |
+-------+---------------------------------------+-------------------+
Figure 3: CBOR Certificate Signature Algorithms
9.3. CBOR Certificate Public Key Algorithms Registry
IANA has created a new registry titled "CBOR Certificate Public Key
Algorithms" under the new heading "CBOR Certificate". The
registration procedure is "Expert Review". The columns of the
registry are Value, X.509 Algorithm, and Reference, where Value is an
integer and the other columns are text strings. The initial contents
of the registry are:
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+-------+---------------------------------------+-------------------+
| Value | X.509 Public Key Algorithm | Reference |
+-------+---------------------------------------+-------------------+
| 0 | id-ecPublicKey + prime384v1 | [[this document]] |
| 1 | id-ecPublicKey + prime512v1 | [[this document]] |
| 2 | id-X25519 | [[this document]] |
| 3 | id-X448 | [[this document]] |
| 4 | id-Ed25519 | [[this document]] |
| 5 | id-Ed448 | [[this document]] |
+-------+---------------------------------------+-------------------+
Figure 4: CBOR Certificate Public Key Algorithms
10. References
10.1. Normative References
[I-D.ietf-cbor-sequence]
Bormann, C., "Concise Binary Object Representation (CBOR)
Sequences", draft-ietf-cbor-sequence-02 (work in
progress), September 2019.
[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>.
[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>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[RFC7925] Tschofenig, H., Ed. and T. Fossati, "Transport Layer
Security (TLS) / Datagram Transport Layer Security (DTLS)
Profiles for the Internet of Things", RFC 7925,
DOI 10.17487/RFC7925, July 2016,
<https://www.rfc-editor.org/info/rfc7925>.
[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>.
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[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>.
10.2. Informative References
[I-D.ietf-tls-dtls13]
Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", draft-ietf-tls-dtls13-34 (work in progress),
November 2019.
[I-D.selander-ace-cose-ecdhe]
Selander, G., Mattsson, J., and F. Palombini, "Ephemeral
Diffie-Hellman Over COSE (EDHOC)", draft-selander-ace-
cose-ecdhe-14 (work in progress), September 2019.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8613] Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
"Object Security for Constrained RESTful Environments
(OSCORE)", RFC 8613, DOI 10.17487/RFC8613, July 2019,
<https://www.rfc-editor.org/info/rfc8613>.
[SECG] "Elliptic Curve Cryptography, Standards for Efficient
Cryptography Group, ver. 2", 2009,
<https://secg.org/sec1-v2.pdf>.
[X.509-IoT]
Forsby, F., Furuhed, M., Papadimitratos, P., and S. Raza,
"Lightweight X.509 Digital Certificates for the Internet
of Things.", Springer, Cham. Lecture Notes of the
Institute for Computer Sciences, Social Informatics and
Telecommunications Engineering, vol 242., July 2018,
<https://doi.org/10.1007/978-3-319-93797-7_14>.
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Appendix A. Example CBOR Certificates
A.1. Example X.509 Certificate
Example RFC 7925 profiled X.509 certificate parsed with OpenSSL
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 128269 (0x1f50d)
Signature Algorithm: ecdsa-with-SHA256
Issuer: CN=RFC test CA
Validity
Not Before: Jan 1 00:00:00 2020 GMT
Not After : Feb 2 00:00:00 2021 GMT
Subject: CN=01-23-45-FF-FE-67-89-AB
Subject Public Key Info:
Public Key Algorithm: id-ecPublicKey
Public-Key: (256 bit)
pub:
04:ae:4c:db:01:f6:14:de:fc:71:21:28:5f:dc:7f:
5c:6d:1d:42:c9:56:47:f0:61:ba:00:80:df:67:88:
67:84:5e:e9:a6:9f:d4:89:31:49:da:e3:d3:b1:54:
16:d7:53:2c:38:71:52:b8:0b:0d:f3:e1:af:40:8a:
95:d3:07:1e:58
ASN1 OID: prime256v1
NIST CURVE: P-256
X509v3 extensions:
X509v3 Key Usage:
Digital Signature
Signature Algorithm: ecdsa-with-SHA256
30:44:02:20:37:38:73:ef:87:81:b8:82:97:ef:23:5c:1f:ac:
cf:62:da:4e:44:74:0d:c2:a2:e6:a3:c6:c8:82:a3:23:8d:9c:
02:20:3a:d9:35:3b:a7:88:68:3b:06:bb:48:fe:ca:16:ea:71:
17:17:34:c6:75:c5:33:2b:2a:f1:cb:73:38:10:a1:fc
The DER encoding of the above certificate is 314 bytes
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308201363081DEA003020102020301F50D300A06082A8648CE3D040302301631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A.2. Example CBOR Certificate Compression
The CBOR certificate compression of the X.509 in CBOR diagnostic
format is
(
1,
h'128269',
"RFC test CA",
1577836800,
1612224000,
h'0123456789AB',
h'02ae4cdb01f614defc7121285fdc7f5c6d1d42c95647f061ba
0080df678867845e',
5,
h'373873EF8781B88297EF235C1FACCF62DA4E44740DC2A2E6A3
C6C882A3238D9C3AD9353BA788683B06BB48FECA16EA711717
34C675C5332B2AF1CB733810A1FC'
)
The CBOR encoding (CBOR sequence) of the CBOR certificate is 136
bytes
01431282696B52464320746573742043411A5E0BE1001A601896004601234567
89AB582102AE4CDB01F614DEFC7121285FDC7F5C6D1D42C95647F061BA0080DF
678867845E055840373873EF8781B88297EF235C1FACCF62DA4E44740DC2A2E6
A3C6C882A3238D9C3AD9353BA788683B06BB48FECA16EA71171734C675C5332B
2AF1CB733810A1FC
A.3. Example Native CBOR Certificate
The corresponfing native CBOR certificate in CBOR diagnostic format
is equal execpt for type and signatureValue
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(
0,
h'128269',
"RFC test CA",
1577836800,
1612224000,
h'0123456789AB',
h'02ae4cdb01f614defc7121285fdc7f5c6d1d42c95647f061
ba0080df678867845e',
5,
h'7F10A063DA8DB2FD49414440CDF85070AC22A266C7F1DFB1
577D9A35A295A8742E794258B76968C097F85542322A0796
0199C13CC0220A9BC729EF2ECA638CFE'
)
The CBOR encoding (CBOR sequence) of the CBOR certificate is 136
bytes
00431282696B52464320746573742043411A5E0BE1001A601896004601234567
89AB582102AE4CDB01F614DEFC7121285FDC7F5C6D1D42C95647F061BA0080DF
678867845E0558407F10A063DA8DB2FD49414440CDF85070AC22A266C7F1DFB1
577D9A35A295A8742E794258B76968C097F85542322A07960199C13CC0220A9B
C729EF2ECA638CFE
Appendix B. X.509 Certificate Profile, ASN.1
IOTCertificate DEFINITIONS EXPLICIT TAGS ::= BEGIN
Certificate ::= SEQUENCE {
tbsCertificate TBSCertificate,
signatureAlgorithm AlgorithmIdentifier,
signatureValue BIT STRING
}
TBSCertificate ::= SEQUENCE {
version [0] INTEGER {v3(2)},
serialNumber INTEGER (1..MAX),
signature AlgorithmIdentifier,
issuer Name,
validity Validity,
subject Name,
subjectPublicKeyInfo SubjectPublicKeyInfo,
extensions [3] Extensions OPTIONAL
}
Name ::= SEQUENCE SIZE (1) OF DistinguishedName
DistinguishedName ::= SET SIZE (1) OF CommonName
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CommonName ::= SEQUENCE {
type OBJECT IDENTIFIER (id-at-commonName),
value UTF8String
}
Validity ::= SEQUENCE {
notBefore UTCTime,
notAfter UTCTime
}
SubjectPublicKeyInfo ::= SEQUENCE {
algorithm AlgorithmIdentifier,
subjectPublicKey BIT STRING
}
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL }
}
Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension
Extension ::= SEQUENCE {
extnId OBJECT IDENTIFIER,
critical BOOLEAN DEFAULT FALSE,
extnValue OCTET STRING
}
id-at-commonName OBJECT IDENTIFIER ::=
{joint-iso-itu-t(2) ds(5) attributeType(4) 3}
END
Authors' Addresses
Shahid Raza
RISE AB
Email: shahid.raza@ri.se
Joel Hoeglund
RISE AB
Email: joel.hoglund@ri.se
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Goeran Selander
Ericsson AB
Email: goran.selander@ericsson.com
John Preuss Mattsson
Ericsson AB
Email: john.mattsson@ericsson.com
Martin Furuhed
Nexus Group
Email: martin.furuhed@nexusgroup.com
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