RFC2511 - Internet X.509 Certificate Request Message Format

Network Working Group M. Myers

Request for Comments: 2511 VeriSign

Category: Standards Track C. Adams

Entrust Technologies

D. Solo

Citicorp

D. Kemp

DoD

March 1999

Internet X.509 Certificate Request Message Format

Status of this Memo

This document specifies an Internet standards track protocol for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "Internet

Official Protocol Standards" (STD 1) for the standardization state

and status of this protocol. Distribution of this memo is unlimited.

1. Abstract

This document describes the Certificate Request Message Format

(CRMF). This syntax is used to convey a request for a certificate to

a Certification Authority (CA) (possibly via a Registration Authority

(RA)) for the purposes of X.509 certificate prodUCtion. The request

will typically include a public key and associated registration

information.

The key Words "MUST", "REQUIRED", "SHOULD", "RECOMMENDED", and "MAY"

in this document (in uppercase, as shown) are to be interpreted as

described in RFC2119.

2. Overview

Construction of a certification request involves the following steps:

a) A CertRequest value is constructed. This value may include the

public key, all or a portion of the end-entity's (EE's) name,

other requested certificate fields, and additional control

information related to the registration process.

b) A proof of possession (of the private key corresponding to the

public key for which a certificate is being requested) value may

be calculated across the CertRequest value.

c) Additional registration information may be combined with the

proof of possession value and the CertRequest structure to form a

CertReqMessage.

d) The CertReqMessage is securely communicated to a CA. Specific

means of secure transport are beyond the scope of this

specification.

3. CertReqMessage Syntax

A certificate request message is composed of the certificate request,

an optional proof of possession field and an optional registration

information field.

CertReqMessages ::= SEQUENCE SIZE (1..MAX) OF CertReqMsg

CertReqMsg ::= SEQUENCE {

certReq CertRequest,

pop ProofOfPossession OPTIONAL,

-- content depends upon key type

regInfo SEQUENCE SIZE(1..MAX) of AttributeTypeAndValue OPTIONAL }

The proof of possession field is used to demonstrate that the entity

to be associated with the certificate is actually in possession of

the corresponding private key. This field may be calculated across

the contents of the certReq field and varies in structure and content

by public key algorithm type and operational mode.

The regInfo field SHOULD only contain supplementary information

related to the context of the certification request when such

information is required to fulfill a certification request. This

information MAY include subscriber contact information, billing

information or other ancillary information useful to fulfillment of

the certification request.

Information directly related to certificate content SHOULD be

included in the certReq content. However, inclusion of additional

certReq content by RAs may invalidate the pop field. Data therefore

intended for certificate content MAY be provided in regInfo.

See Section 8 and Appendix B for example regInfo contents.

4. Proof of Possession (POP)

In order to prevent certain attacks and to allow a CA/RA to properly

check the validity of the binding between an end entity and a key

pair, the PKI management operations specified here make it possible

for an end entity to prove that it has possession of (i.e., is able

to use) the private key corresponding to the public key for which a

certificate is requested. A given CA/RA is free to choose how to

enforce POP (e.g., out-of-band procedural means versus the CRMF in-

band message) in its certification exchanges (i.e., this may be a

policy issue). However, it is MANDATED that CAs/RAs MUST enforce POP

by some means because there are currently many non-PKIX operational

protocols in use (various electronic mail protocols are one example)

that do not eXPlicitly check the binding between the end entity and

the private key. Until operational protocols that do verify the

binding (for signature, encryption, and key agreement key pairs)

exist, and are ubiquitous, this binding can only be assumed to have

been verified by the CA/RA. Therefore, if the binding is not verified

by the CA/RA, certificates in the Internet Public-Key Infrastructure

end up being somewhat less meaningful.

POP is accomplished in different ways depending on the type of key

for which a certificate is requested. If a key can be used for

multiple purposes (e.g., an RSA key) then any of the methods MAY be

used.

This specification allows for cases where POP is validated by the CA,

the RA, or both. Some policies may require the CA to verify POP

during certification, in which case the RA MUST forward the end

entity's CertRequest and ProofOfPossession fields unaltered to the

CA, and as an option MAY also verify POP. If the CA is not required

by policy to verify POP, then the RA SHOULD forward the end entity's

request and proof unaltered to the CA as above. If this is not

possible (for example because the RA verifies POP by an out-of-band

method), then the RA MAY attest to the CA that the required proof has

been validated. If the CA uses an out-of-band method to verify POP

(such as physical delivery of CA-generated private keys), then the

ProofOfPossession field is not used.

4.1 Signature Keys

For signature keys, the end entity can sign a value to prove

possession of the private key.

4.2 Key Encipherment Keys

For key encipherment keys, the end entity can provide the private key

to the CA/RA, or can be required to decrypt a value in order to prove

possession of the private key. Decrypting a value can be achieved

either directly or indirectly.

The direct method is for the RA/CA to issue a random challenge to

which an immediate response by the end entity is required.

The indirect method is to issue a certificate which is encrypted for

the end entity (and have the end entity demonstrate its ability to

decrypt this certificate in a confirmation message). This allows a CA

to issue a certificate in a form which can only be used by the

intended end entity.

4.3 Key Agreement Keys

For key agreement keys, the end entity can use any of the three

methods given in Section 5.2 for encryption keys. For the direct and

indirect methods, the end entity and the PKI management entity (i.e.,

CA or RA) must establish a shared secret key in order to prove that

the end entity has possession of the private key (i.e., in order to

decrypt the encrypted certificate or to construct the response to the

issued challenge). Note that this need not impose any restrictions

on the keys that can be certified by a given CA -- in particular, for

Diffie-Hellman keys the end entity may freely choose its algorithm

parameters -- provided that the CA can generate a short-term (or

one-time) key pair with the appropriate parameters when necessary.

The end entity may also MAC the certificate request (using a shared

secret key derived from a Diffie-Hellman computation) as a fourth

alternative for demonstrating POP. This option may be used only if

the CA already has a DH certificate that is known to the end entity

and if the EE is willing to use the CA's DH parameters.

4.4 Proof of Possession Syntax

ProofOfPossession ::= CHOICE {

raVerified [0] NULL,

-- used if the RA has already verified that the requester is in

-- possession of the private key

signature [1] POPOSigningKey,

keyEncipherment [2] POPOPrivKey,

keyAgreement [3] POPOPrivKey }

POPOSigningKey ::= SEQUENCE {

popoSKINput [0] POPOSigningKeyInput OPTIONAL,

algorithmIdentifier AlgorithmIdentifier,

signature BIT STRING }

-- The signature (using "algorithmIdentifier") is on the

-- DER-encoded value of poposkInput. NOTE: If the CertReqMsg

-- certReq CertTemplate contains the subject and publicKey values,

-- then poposkInput MUST be omitted and the signature MUST be

-- computed on the DER-encoded value of CertReqMsg certReq. If

-- the CertReqMsg certReq CertTemplate does not contain the public

-- key and subject values, then poposkInput MUST be present and

-- MUST be signed. This strategy ensures that the public key is

-- not present in both the poposkInput and CertReqMsg certReq

-- CertTemplate fields.

POPOSigningKeyInput ::= SEQUENCE {

authInfo CHOICE {

sender [0] GeneralName,

-- used only if an authenticated identity has been

-- established for the sender (e.g., a DN from a

-- previously-issued and currently-valid certificate)

publicKeyMAC PKMACValue },

-- used if no authenticated GeneralName currently exists for

-- the sender; publicKeyMAC contains a password-based MAC

-- on the DER-encoded value of publicKey

publicKey SubjectPublicKeyInfo } -- from CertTemplate

PKMACValue ::= SEQUENCE {

algId AlgorithmIdentifier,

-- the algorithm value shall be PasswordBasedMac

-- {1 2 840 113533 7 66 13}

-- the parameter value is PBMParameter

value BIT STRING }

POPOPrivKey ::= CHOICE {

thisMessage [0] BIT STRING,

-- posession is proven in this message (which contains the private

-- key itself (encrypted for the CA))

subsequentMessage [1] SubsequentMessage,

-- possession will be proven in a subsequent message

dhMAC [2] BIT STRING }

-- for keyAgreement (only), possession is proven in this message

-- (which contains a MAC (over the DER-encoded value of the

-- certReq parameter in CertReqMsg, which must include both subject

-- and publicKey) based on a key derived from the end entity's

-- private DH key and the CA's public DH key);

-- the dhMAC value MUST be calculated as per the directions given

-- in Appendix A.

SubsequentMessage ::= INTEGER {

encrCert (0),

-- requests that resulting certificate be encrypted for the

-- end entity (following which, POP will be proven in a

-- confirmation message)

challengeResp (1) }

-- requests that CA/RA engage in challenge-response exchange with

-- end entity in order to prove private key possession

It is expected that protocols which incorporate this specification

will include the confirmation and challenge-response messages

necessary to a complete protocol.

4.4.1 Use of Password-Based MAC

The following algorithm SHALL be used when publicKeyMAC is used in

POPOSigningKeyInput to prove the authenticity of a request.

PBMParameter ::= SEQUENCE {

salt OCTET STRING,

owf AlgorithmIdentifier,

-- AlgId for a One-Way Function (SHA-1 recommended)

iterationCount INTEGER,

-- number of times the OWF is applied

mac AlgorithmIdentifier

-- the MAC AlgId (e.g., DES-MAC, Triple-DES-MAC [PKCS11],

} -- or HMAC [RFC2104, RFC2202])

The process of using PBMParameter to compute publicKeyMAC and so

authenticate the origin of a public key certification request

consists of two stages. The first stage uses shared secret

information to produce a MAC key. The second stage MACs the public

key in question using this MAC key to produce an authenticated value.

Initialization of the first stage of algorithm assumes the existence

of a shared secret distributed in a trusted fashion between CA/RA and

end-entity. The salt value is appended to the shared secret and the

one way function (owf) is applied iterationCount times, where the

salted secret is the input to the first iteration and, for each

successive iteration, the input is set to be the output of the

previous iteration, yielding a key K.

In the second stage, K and the public key are inputs to HMAC as

documented in [HMAC] to produce a value for publicKeyMAC as follows:

publicKeyMAC = Hash( K XOR opad, Hash( K XOR ipad, public key) )

where ipad and opad are defined in [RFC2104].

The AlgorithmIdentifier for owf SHALL be SHA-1 {1 3 14 3 2 26} and

for mac SHALL be HMAC-SHA1 {1 3 6 1 5 5 8 1 2}.

5. CertRequest syntax

The CertRequest syntax consists of a request identifier, a template

of certificate content, and an optional sequence of control

information.

CertRequest ::= SEQUENCE {

certReqId INTEGER, -- ID for matching request and reply

certTemplate CertTemplate, -- Selected fields of cert to be issued

controls Controls OPTIONAL } -- Attributes affecting issuance

CertTemplate ::= SEQUENCE {

version [0] Version OPTIONAL,

serialNumber [1] INTEGER OPTIONAL,

signingAlg [2] AlgorithmIdentifier OPTIONAL,

issuer [3] Name OPTIONAL,

validity [4] OptionalValidity OPTIONAL,

subject [5] Name OPTIONAL,

publicKey [6] SubjectPublicKeyInfo OPTIONAL,

issuerUID [7] UniqueIdentifier OPTIONAL,

subjectUID [8] UniqueIdentifier OPTIONAL,

extensions [9] Extensions OPTIONAL }

OptionalValidity ::= SEQUENCE {

notBefore [0] Time OPTIONAL,

notAfter [1] Time OPTIONAL } --at least one must be present

Time ::= CHOICE {

utcTime UTCTime,

generalTime GeneralizedTime }

6. Controls Syntax

The generator of a CertRequest may include one or more control values

pertaining to the processing of the request.

Controls ::= SEQUENCE SIZE(1..MAX) OF AttributeTypeAndValue

The following controls are defined (it is recognized that this list

may expand over time): regToken; authenticator; pkiPublicationInfo;

pkiArchiveOptions; oldCertID; protocolEncrKey.

6.1 Registration Token Control

A regToken control contains one-time information (either based on a

secret value or on knowledge) intended to be used by the CA to verify

the identity of the subject prior to issuing a certificate. Upon

receipt of a certification request containing a value for regToken,

the receiving CA verifies the information in order to confirm the

identity claimed in the certification request.

The value for regToken may be generated by the CA and provided out of

band to the subscriber, or may otherwise be available to both the CA

and the subscriber. The security of any out-of-band exchange should

be commensurate with the risk of the CA accepting an intercepted

value from someone other than the intended subscriber.

The regToken control would typically be used only for initialization

of an end entity into the PKI, whereas the authenticator control (see

Section 7.2) would typically be used for initial as well as

subsequent certification requests.

In some instances of use the value for regToken could be a text

string or a numeric quantity such as a random number. The value in

the latter case could be encoded either as a binary quantity or as a

text string representation of the binary quantity. To ensure a

uniform encoding of values regardless of the nature of the quantity,

the encoding of regToken SHALL be UTF8.

6.2 Authenticator Control.

An authenticator control contains information used in an ongoing

basis to establish a non-cryptographic check of identity in

communication with the CA. Examples include: mother's maiden name,

last four digits of social security number, or other knowledge-based

information shared with the subscriber's CA; a hash of such

information; or other information produced for this purpose. The

value for an authenticator control may be generated by the subscriber

or by the CA.

In some instances of use the value for regToken could be a text

string or a numeric quantity such as a random number. The value in

the latter case could be encoded either as a binary quantity or as a

text string representation of the binary quantity. To ensure a

uniform encoding of values regardless of the nature of the quantity,

the encoding of authenticator SHALL be UTF8.

6.3 Publication Information Control

The pkiPublicationInfo control enables subscribers to control the

CA's publication of the certificate. It is defined by the following

syntax:

PKIPublicationInfo ::= SEQUENCE {

action INTEGER {

dontPublish (0),

pleasePublish (1) },

pubInfos SEQUENCE SIZE (1..MAX) OF SinglePubInfo OPTIONAL }

-- pubInfos MUST NOT be present if action is "dontPublish"

-- (if action is "pleasePublish" and pubInfos is omitted,

-- "dontCare" is assumed)

SinglePubInfo ::= SEQUENCE {

pubMethod INTEGER {

dontCare (0),

x500 (1),

web (2),

ldap (3) },

pubLocation GeneralName OPTIONAL }

If the dontPublish option is chosen, the requester indicates that the

PKI should not publish the certificate (this may indicate that the

requester intends to publish the certificate him/herself).

If the dontCare method is chosen, or if the PKIPublicationInfo

control is omitted from the request, the requester indicates that the

PKI MAY publish the certificate using whatever means it chooses.

If the requester wishes the certificate to appear in at least some

locations but wishes to enable the CA to make the certificate

available in other repositories, set two values of SinglePubInfo for

pubInfos: one with x500, web or ldap value and one with dontCare.

The pubLocation field, if supplied, indicates where the requester

would like the certificate to be found (note that the CHOICE within

GeneralName includes a URL and an IP address, for example).

6.4 Archive Options Control

The pkiArchiveOptions control enables subscribers to supply

information needed to establish an archive of the private key

corresponding to the public key of the certification request. It is

defined by the following syntax:

PKIArchiveOptions ::= CHOICE {

encryptedPrivKey [0] EncryptedKey,

-- the actual value of the private key

keyGenParameters [1] KeyGenParameters,

-- parameters which allow the private key to be re-generated

archiveRemGenPrivKey [2] BOOLEAN }

-- set to TRUE if sender wishes receiver to archive the private

-- key of a key pair which the receiver generates in response to

-- this request; set to FALSE if no archival is desired.

EncryptedKey ::= CHOICE {

encryptedValue EncryptedValue,

envelopedData [0] EnvelopedData }

-- The encrypted private key MUST be placed in the envelopedData

-- encryptedContentInfo encryptedContent OCTET STRING.

EncryptedValue ::= SEQUENCE {

intendedAlg [0] AlgorithmIdentifier OPTIONAL,

-- the intended algorithm for which the value will be used

symmAlg [1] AlgorithmIdentifier OPTIONAL,

-- the symmetric algorithm used to encrypt the value

encSymmKey [2] BIT STRING OPTIONAL,

-- the (encrypted) symmetric key used to encrypt the value

keyAlg [3] AlgorithmIdentifier OPTIONAL,

-- algorithm used to encrypt the symmetric key

valueHint [4] OCTET STRING OPTIONAL,

-- a brief description or identifier of the encValue content

-- (may be meaningful only to the sending entity, and used only

-- if EncryptedValue might be re-examined by the sending entity

-- in the future)

encValue BIT STRING }

KeyGenParameters ::= OCTET STRING

An alternative to sending the key is to send the information about

how to re-generate the key using the KeyGenParameters choice (e.g.,

for many RSA implementations one could send the first random numbers

tested for primality). The actual syntax for this parameter may be

defined in a subsequent version of this document or in another

standard.

6.5 OldCert ID Control

If present, the OldCertID control specifies the certificate to be

updated by the current certification request. The syntax of its

value is:

CertId ::= SEQUENCE {

issuer GeneralName,

serialNumber INTEGER

}

6.6 Protocol Encryption Key Control

If present, the protocolEncrKey control specifies a key the CA is to

use in encrypting a response to CertReqMessages.

This control can be used when a CA has information to send to the

subscriber that needs to be encrypted. Such information includes a

private key generated by the CA for use by the subscriber.

The encoding of protocolEncrKey SHALL be SubjectPublicKeyInfo.

7. Object Identifiers

The OID id-pkix has the value

id-pkix OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)

dod(6) internet(1) security(5) mechanisms(5) pkix(7) }

-- arc for Internet X.509 PKI protocols and their components

id-pkip OBJECT IDENTIFIER :: { id-pkix pkip(5) }

-- Registration Controls in CRMF

id-regCtrl OBJECT IDENTIFIER ::= { id-pkip regCtrl(1) }

id-regCtrl-regToken OBJECT IDENTIFIER ::= { id-regCtrl 1 }

id-regCtrl-authenticator OBJECT IDENTIFIER ::= { id-regCtrl 2 }

id-regCtrl-pkiPublicationInfo OBJECT IDENTIFIER ::= { id-regCtrl 3 }

id-regCtrl-pkiArchiveOptions OBJECT IDENTIFIER ::= { id-regCtrl 4 }

id-regCtrl-oldCertID OBJECT IDENTIFIER ::= { id-regCtrl 5 }

id-regCtrl-protocolEncrKey OBJECT IDENTIFIER ::= { id-regCtrl 6 }

-- Registration Info in CRMF

id-regInfo OBJECT IDENTIFIER ::= { id-pkip id-regInfo(2) }

id-regInfo-asciiPairs OBJECT IDENTIFIER ::= { id-regInfo 1 }

--with syntax OCTET STRING

id-regInfo-certReq OBJECT IDENTIFIER ::= { id-regInfo 2 }

--with syntax CertRequest

8. Security Considerations

The security of CRMF delivery is reliant upon the security mechanisms

of the protocol or process used to communicate with CAs. Such

protocol or process needs to ensure the integrity, data origin

authenticity, and privacy of the message. Encryption of a CRMF is

strongly recommended if it contains subscriber-sensitive information

and if the CA has an encryption certificate that is known to the end

entity.

9. References

[HMAC] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed-

Hashing for Message Authentication", RFC2104, February 1997.

10. Acknowledgments

The authors gratefully acknowledge the contributions of Barbara Fox,

Warwick Ford, Russ Housley and John Pawling, whose review and

comments significantly clarified and improved the utility of this

specification.

11. Authors' Addresses

Michael Myers

VeriSign, Inc.

1390 Shorebird Way

Mountain View, CA 94019

EMail: mmyers@verisign.com

Carlisle Adams

Entrust Technologies

750 Heron Road, Suite E08

Ottawa, Canada, K1V 1A7

EMail: cadams@entrust.com

Dave Solo

Citicorp

666 Fifth Ave, 3rd Floor

New York, Ny 10103

EMail: david.solo@citicorp.com

David Kemp

National Security Agency

Suite 6734

9800 Savage Road

Fort Meade, MD 20755

EMail: dpkemp@missi.ncsc.mil

Appendix A. Constructing "dhMAC"

This Appendix describes the method for computing the bit string

"dhMAC" in the proof-of-possession POPOPrivKey structure for Diffie-

Hellman certificate requests.

1. The entity generates a DH public/private key-pair.

The DH parameters used to calculate the public SHOULD be those

specified in the CA's DH certificate.

From CA's DH certificate:

CApub = g^x mod p (where g and p are the established DH

parameters and x is the CA's private

DH component)

For entity E:

DH private value = y

Epub = DH public value = g^y mod p

2. The MACing process will then consist of the following steps.

a) The value of the certReq field is DER encoded, yielding a binary

string. This will be the 'text' referred to in [HMAC], the data to

which HMAC-SHA1 is applied.

b) A shared DH secret is computed, as follows,

shared secret = Kec = g^xy mod p

[This is done by the entity E as CApub^y and by the CA as Epub^x,

where CApub is retrieved from the CA's DH certificate and Epub is

retrieved from the actual certification request.]

c) A key K is derived from the shared secret Kec and the subject and

issuer names in the CA's certificate as follows:

K = SHA1(DER-encoded-subjectName Kec DER-encoded-issuerName)

where "" means concatenation. If subjectName in the CA

certificate is an empty SEQUENCE then DER-encoded-subjectAltName

should be used instead; similarly, if issuerName is an empty

SEQUENCE then DER-encoded-issuerAltName should be used instead.

d) Compute HMAC-SHA1 over the data 'text' as per [RFC2104] as:

SHA1(K XOR opad, SHA1(K XOR ipad, text))

where,

opad (outer pad) = the byte 0x36 repeated 64 times

and

ipad (inner pad) = the byte 0x5C repeated 64 times.

Namely,

(1) Append zeros to the end of K to create a 64 byte string

(e.g., if K is of length 16 bytes it will be appended with

48 zero bytes 0x00).

(2) XOR (bitwise exclusive-OR) the 64 byte string computed in

step (1) with ipad.

(3) Append the data stream 'text' to the 64 byte string

resulting from step (2).

(4) Apply SHA1 to the stream generated in step (3).

(5) XOR (bitwise exclusive-OR) the 64 byte string computed in

step (1) with opad.

(6) Append the SHA1 result from step (4) to the 64 byte string

resulting from step (5).

(7) Apply SHA1 to the stream generated in step (6) and output

the result.

Sample code is also provided in [RFC2104, RFC2202].

e) The output of (d) is encoded as a BIT STRING (the value "dhMAC").

3. The proof-of-possession process requires the CA to carry out

steps (a) through (d) and then simply compare the result of step

(d) with what it received as the "dhMAC" value. If they match then

the following can be concluded.

1) The Entity possesses the private key corresponding to the

public key in the certification request (because it needed the

private key to calculate the shared secret).

2) Only the intended CA can actually verify the request (because

the CA requires its own private key to compute the same shared

secret). This helps to protect from rogue CAs.

References

[RFC2104] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed

Hashing for Message Authentication", RFC2104, February

1997.

[RFC2202] Cheng, P. and R. Glenn, "Test Cases for HMAC-MD5 and HMAC-

SHA-1", RFC2202, September 1997.

Acknowledgements

The details of this Appendix were provided by Hemma Prafullchandra.

Appendix B. Use of RegInfo for Name-Value Pairs

The "value" field of the id-regInfo-utf8Pairs OCTET STRING (with

"tag" field equal to 12 and appropriate "length" field) will contain

a series of UTF8 name/value pairs.

This Appendix lists some common examples of such pairs for the

purpose of promoting interoperability among independent

implementations of this specification. It is recognized that this

list is not exhaustive and will grow with time and implementation

experience.

B.1. Example Name/Value Pairs

When regInfo is used to convey one or more name-value pairs (via id-

regInfo-utf8Pairs), the first and subsequent pairs SHALL be

structured as follows:

[name?value][%name?value]*%

This string is then encoded into an OCTET STRING and placed into the

regInfo SEQUENCE.

Reserved characters are encoded using the %xx mechanism of [RFC1738],

unless they are used for their reserved purposes.

The following table defines a recommended set of named elements.

The value in the column "Name Value" is the exact text string that

will appear in the regInfo.

Name Value

----------

version -- version of this variation of regInfo use

corp_company -- company affiliation of subscriber

org_unit -- organizational unit

mail_firstName -- personal name component

mail_middleName -- personal name component

mail_lastName -- personal name component

mail_email -- subscriber's email address

joBTitle -- job title of subscriber

employeeID -- employee identification number or string

mailStop -- mail stop

issuerName -- name of CA

subjectName -- name of Subject

validity -- validity interval

For example:

version?1%corp_company?Acme, Inc.%org_unit?Engineering%

mail_firstName?John%mail_lastName?Smith%jobTitle?Team Leader%

mail_email?john@acme.com%

B.1.1. IssuerName, SubjectName and Validity Value Encoding

When they appear in id-regInfo-utf8Pairs syntax as named elements,

the encoding of values for issuerName, subjectName and validity SHALL

use the following syntax. The characters [] indicate an optional

field, ::= and have their usual BNF meanings, and all other symbols

(except spaces which are insignificant) outside non-terminal names

are terminals. Alphabetics are case-sensitive.

issuerName ::= <names>

subjectName ::= <names>

<validity> ::= validity ? [<notbefore>]-[<notafter>]

Where <time> is UTC time in the form YYYYMMDD[HH[MM[SS]]]. HH, MM,

and SS default to 00 and are omitted if at the and of value 00.

Example validity encoding:

validity?-19991231%

is a validity interval with no value for notBefore and a value of

December 31, 1999 for notAfter.

Each name comprises a single character name form identifier followed

by a name value of one or UTF8 characters. Within a name value, when

it is necessary to disambiguate a character which has formatting

significance at an outer level, the escape sequence %xx SHALL be

used, where xx represents the hex value for the encoding concerned.

The percent symbol is represented by %%.

Name forms and value formats are as follows:

X.500 Directory name form (identifier "X"):

Standard attribute type <stdat> is an alphabetic attribute type

identifier from the following set:

C (country)

L (locality)

ST (state or province)

O (organization)

OU (organizational unit)

CN (common name)

STREET (street address)

E (E-mail address).

<avalue> is a name component in the form of a UTF8 character string

of 1 to 64 characters, with the restriction that in the IA5 subset of

UTF8 only the characters of ASN.1 PrintableString may be used.

Other name form (identifier "O"):

E-mail address (rfc822name) name form (identifier "E"):

DNS name form (identifier "D"):

URI name form (identifier "U"):

IP address (identifier "I"):

For example:

issuerName?XOU=Our CA,O=Acme,C=US%

subjectName?XCN=John Smith, O=Acme, C=US, E=john@acme.com%

References

[RFC1738] Berners-Lee, T., Masinter, L. and M. McCahill,

"Uniform Resource Locators (URL)", RFC1738, December 1994.

Appendix C. ASN.1 Structures and OIDs

PKIXCRMF {iso(1) identified-organization(3) dod(6) internet(1)

security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-crmf(5)}

CRMF DEFINITIONS IMPLICIT TAGS ::=

BEGIN

IMPORTS

-- Directory Authentication Framework (X.509)

Version, AlgorithmIdentifier, Name, Time,

SubjectPublicKeyInfo, Extensions, UniqueIdentifier

FROM PKIX1Explicit88 {iso(1) identified-organization(3) dod(6)

internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)

id-pkix1-explicit-88(1)}

-- Certificate Extensions (X.509)

GeneralName

FROM PKIX1Implicit88 {iso(1) identified-organization(3) dod(6)