ssh-cmpclient-g3

ssh-cmpclient-g3 — CMP enrollment client

Synopsis

ssh-cmpclient-g3 command [options] access [name]

Where command is one of the following:

     INITIALIZE psk|racerts keypair template
     ENROLL certs|racerts keypair template
     UPDATE certs [keypair]
     POLL psk|certs|racerts id

     RECOVER psk|certs|racerts template
     REVOKE psk|certs|racerts template
     TUNNEL racerts template

Most commands can accept the following options:
     -B            Perform key backup for subject keys.
     -o prefix     Save result into files with prefix.
     -O filename   Save the result into the specified file. 
                   If there is more than one result file, 
                   the remaining results are rejected.
     -C file       CA certificate from this file.
     -S url        Use this SOCKS server to access the CA.
     -H url        Use this HTTP proxy to access the CA.
     -E            PoP by encryption (CA certificate needed).
     -v num        Protocol version 1|2 of the CA platform. Default is 2.
     -y            Non-interactive mode. All questions answered with 'y'.
     -N file       Specifies a file to stir to the random pool.

The following identifiers are used to specify options:
     psk      -p refnum:key (reference number and pre-shared key)
              -p file (containing refnum:key)
              -i number (iteration count, default 1024)
     certs    -c file (certificate file) -k url (private-key URL) 
     racerts  -R file (RA certificate file) -k url (RA private-key URL)
     keypair  -P url (private-key URL)
     id       -I number (polling ID)
     template -T file (certificate template)
              -s subject-ldap[;type=value]
              -u key-usage-name[;key-usage-name]
              -U extended-key-usage-name[;extended-key-usage-name]
     access   URL where the CA listens for requests.
     name     LDAP name for the issuing CA (if -C is not given).

Key URLs are either valid external key paths or in the format:
     "generate://savetype:passphrase@keytype:size/save-file-prefix"
     "file://passphrase/relative-key-file-path"
     "file:relative-key-file-path"
     "any-key-file-path"

The key generation "savetype" can be:
 - ssh2, secsh2, secsh (Secure Shell 2 key type)
 - ssh1, secsh1 (legacy Secure Shell 1 key type)
 - pkcs1 (PKCS #1 format)
 - pkcs8s (passphrase-protected PKCS #8, "shrouded PKCS #8")
 - pkcs8 (plain-text PKCS #8)
 - x509 (SSH-proprietary X.509 library key type)

     -h Prints usage message.
     -F Prints key usage extension and keytype instructions.
     -e Prints command-line examples.

Description

The ssh-cmpclient-g3 command-line tool (ssh-cmpclient-g3.exe on Windows) is a certificate enrollment client that uses the CMP protocol. It can generate an RSA or DSA public-key pair and get certificates for their public components. CMP is specified by the IETF PKIX Working Group for certificate life-cycle management, and is supported by some CA platforms, such as Entrust PKI and RSA Keon.

Commands

The ssh-cmpclient-g3 command-line command keywords are listed below. Shorthands longer than three letters can be used to identify the command. The commands are case-insensitive. The user must specify the CA address URL for each command. Here the term "user" refers to a user, program, or hardware device.

INITIALIZE

Requests the user's initial certificate. The request is authenticated using the reference number and the corresponding key (PSK) received from the CA or RA using some out-of-band mechanism.

The user must specify the PSK, the asymmetric key pair, and a subject name.

ENROLL

Requests a new certificate when the user already has a valid certificate for the key. This request is similar to initialize except that it is authenticated using public-key methods.

POLL

Polls for a certificate when a request was not immediately accepted.

UPDATE

Requests an update of an existing certificate (replacement). The issued certificate will be similar to the existing certificate (names, flags, and other extensions). The user can change the key, and the validity times are updated by the CA. This request is authenticated by a valid existing key pair and a certificate.

RECOVER

Requests recovery of a backed-up key. This request is authenticated either by PSK-based or certificate-based authentication. The template describes the certificate whose private key has already been backed up and should be recovered. Users can only recover keys they have backed up themselves.

REVOKE

Requests revocation for a key specified in the template. Authentication of the request is made using a PSK or a certificate belonging to the same user as the subject of revocation.

TUNNEL

Operates in RA tunnel mode. Reads requests and optionally modifies the subject name, alternative names, and extensions based on the command line. Approves the request and sends it to the CA.

Options

The ssh-cmpclient-g3 command-line options are listed below. Note that when a file name is specified, an existing file with the same name will be overwritten. When subject names or other strings that contain spaces are given on the command line, they should be enclosed in double quotes.

-B: Requests private key backup to be performed for the initialize, enroll, and update commands.
-o prefix: Saves resulting certificates and CRLs into files with the given prefix. The prefix is first appended by a number, followed by the file extension .crt or .crl, depending on the type of object.
-O filename: Saves the result into the specified absolute filename. If there is more than one result file, the remaining results are rejected.
-C file: Specifies the file path that contains the CA certificate. If key backup is done, the file name must be given, but in most cases the LDAP name of the CA can be given instead.
-S url: Specifies the SOCKS URL if the CA is located behind a SOCKS- enabled firewall. The format of the URL is: socks://[username@]server[:port][/network/bits[,network/bits]]
-H url: Uses the given HTTP proxy server to access the CA. The format of the URL is: http://server[:port]/
-E: Performs encryption proof of possession if the CA supports it. In this method of PoP, the request is not signed, but instead the PoP is established based on the ability to decrypt the certificates received from the CA. The CA encrypts the certificates with the user's public key before sending them to the user.
-v num: Selects the CMP protocol version. This is either value 1, for an RFC 2510-based protocol, or 2 (the default) for CMPv2.
-N file: Specifies a file to be used as an entropy source during key generation.

The usage line uses the following meta commands:

psk

The reference number and the corresponding key value given by the CA or RA.

-p refnum:key|file

refnum and key are character strings shared among the CA and the user. refnum identifies the secret key used to authenticate the message. The refnum string must not contain colon characters.

Alternatively, a filename containing the reference number and the key can be given as the argument.

-i number

number indicates the key hashing iteration count.

certs

The user's existing key and certificate for authentication.

-k url: URL specifying the private key location. This is an external key URL whose format is specified in the section called “Synopsis”.
-c file: Path to the file that contains the certificate issued to the public key given in the -k option argument.

racerts

In RA mode, the RA key and certificate for authentication.

-k url: URL specifying the private key location. This is an external key URL whose format is specified in the section called “Synopsis”.
-R file: Path to the file that contains the RA certificate issued to the public key given in the -k option argument.

keypair

The subject key pair to be certified.

-P url: URL specifying the private key location. This is an external key URL whose format is specified in the section called “Synopsis”.

id

Polling ID used if the PKI action is left pending.

-I number: Polling transaction ID number given by the RA or CA if the action is left pending.

template

The subject name and flags to be certified.

-T file

The file containing the certificate used as the template for the operation. Values used to identify the subject are read from this, but the user can overwrite the key, key-usage flags, or subject names.

-s subject-ldap[;type=value]*

A subject name in reverse LDAP format, that is, the most general component first, and alternative subject names. The name subject-ldap will be copied into the request verbatim.

A typical choice would be a DN in the format "C=US,O=SSH,CN=Some Body", but in principle this can be anything that is usable for the resulting certificate.

The possible type values are ip, email, dn, dns, uri, and rid.

-u key-usage-name[;key-usage-name]*

Requested key usage purpose code. The following codes are recognized: digitalSignature, nonRepudiation, keyEncipherment, dataEncipherment, keyAgreement, keyCertSign, cRLSign, encipherOnly, decipherOnly, and help. The special keyword help lists the supported key usages which are defined in RFC 3280.

-U extended-key-usage-name[;extended-key-usage-name]*

Requested extended key usage code. The following codes, in addition to user-specified dotted OID values are recognized: serverAuth, clientAuth, codeSigning, emailProtection, timeStamping, ikeIntermediate, and smartCardLogon.

access

Specifies the CA address in URL format. Possible access methods are HTTP (http://host:port/path), or plain TCP (tcp://host:port/path). If the host address is an IPv6 address, it must be enclosed in square brackets (http://[IPv6-address]:port/).

name

Optionally specifies the destination CA name for the operation, in case a CA certificate was not given using the option -C.

Examples

Initial Certificate Enrollment

This example provides commands for enrolling an initial certificate for digital signature use. It generates a private key into a PKCS #8 plaintext file named initial.prv, and stores the enrolled certificate into file initial-0.crt. The user is authenticated to the CA with the key identifier (refnum) 62154 and the key ssh. The subject name and alternative IP address are given, as well as key-usage flags. The CA address is pki.ssh.com, the port 8080, and the CA name to access Test CA 1.

$ ssh-cmpclient-g3 INITIALIZE \
   -P generate://pkcs8@rsa:1024/initial -o initial \
   -p 62154:ssh \
   -s 'C=FI,O=SSH,CN=Example/initial;IP=1.2.3.4' \
   -u digitalsignature \
   http://pki.ssh.com:8080/pkix/ \
   'C=FI, O=SSH Communications Security Corp, CN=SSH Test CA 1 No Liabilities'

As a response the command presents the issued certificate to the user, and the user accepts it by typing yes at the prompt.

Certificate =
  SubjectName = <C=FI, O=SSH, CN=Example/initial>
  IssuerName = <C=FI, O=SSH Communications Security Corp, 
    CN=SSH Test CA 1 No Liabilities>
  SerialNumber= 8017690
  SignatureAlgorithm = rsa-pkcs1-sha1
  Validity = ...
  PublicKeyInfo = ...
  Extensions =
      Viewing specific name types = IP = 1.2.3.4
    KeyUsage = DigitalSignature
    CRLDistributionPoints = ...
    AuthorityKeyID =
      KeyID = 3d:cb:be:20:64:49:16:1d:88:b7:98:67:93:f0:5d:42:81:2e:bd:0c
    SubjectKeyID =
      KeyId = 6c:f4:0e:ba:b9:ef:44:37:db:ad:1f:fc:46:e0:25:9f:c8:ce:cb:da
  Fingerprints =
    MD5 = b7:6d:5b:4d:e0:94:d1:1f:ec:ca:c2:ed:68:ac:bf:56
    SHA-1 = 4f:de:73:db:ff:e8:7d:42:c4:7d:e1:79:1f:20:43:71:2f:81:ff:fa

Do you accept the certificate above? yes

Key update

Before the certificate expires, a new certificate with updated validity period should be enrolled. ssh-cmpclient-g3 supports key update, where a new private key is generated and the key update request is authenticated with the old (still valid) certificate. The old certificate is also used as a template for issuing the new certificate, so the identity of the user will not be changed during the key update. With the following command you can update the key pair, which was enrolled in the previous example. Presenting the resulting certificate has been left out.

$ ssh-cmpclient-g3 UPDATE \
   -k initial.prv -c initial-0.crt -P \
   generate://pkcs8@rsa:1024/updatedcert -o updatedcert \
   http://pki.ssh.com:8080/pkix/ \
   "C=FI, O=SSH Communications Security Corp, CN=SSH Test CA 1 No Liabilities"

The new key pair can be found in the files with the updatedcert prefix. The policy of the issuing CA needs to also allow automatic key updates if ssh-cmpclient-g3 is used in the UPDATE mode.