Generic message options

-cmd ir|cr|kur|p10cr|rr|genm

CMP command to execute. Currently implemented commands are:

-infotype name

Set InfoType name to use for requesting specific info in genm, e.g., "signKeyPairTypes".

-geninfo OID:int:N

generalInfo integer values to place in request PKIHeader with given OID, e.g., "1.2.3.4:int:56789".

Certificate enrollment options

-newkey filename|uri

The source of the private or public key for the certificate being requested. Defaults to the public key in the PKCS#10 CSR given with the -csr option, the public key of the reference certificate, or the current client key.

The public portion of the key is placed in the certification request.

Unless -cmd p10cr, -popo -1, or -popo 0 is given, the private key will be needed as well to provide the proof of possession (POPO), where the -key option may provide a fallback.

-newkeypass arg

Pass phrase source for the key given with the -newkey option. If not given here, the password will be prompted for if needed.

For more information about the format of arg see openssl-passphrase-options(1).

-subject name

X509 Distinguished Name (DN) of subject to use in the requested certificate template. If the NULL-DN ("/") is given then no subject is placed in the template. Default is the subject DN of any PKCS#10 CSR given with the -csr option. For KUR, a further fallback is the subject DN of the reference certificate (see -oldcert) if provided. This fallback is used for IR and CR only if no SANs are set.

If provided and neither -cert nor -oldcert is given, the subject DN is used as fallback sender of outgoing CMP messages.

The argument must be formatted as /type0=value0/type1=value1/type2=.... Special characters may be escaped by "\" (backslash); whitespace is retained. Empty values are permitted, but the corresponding type will not be included. Giving a single "/" will lead to an empty sequence of RDNs (a NULL-DN). Multi-valued RDNs can be formed by placing a "+" character instead of a "/" between the AttributeValueAssertions (AVAs) that specify the members of the set. Example:

"/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe"

-issuer name

X509 issuer Distinguished Name (DN) of the CA server to place in the requested certificate template in IR/CR/KUR. If the NULL-DN ("/") is given then no issuer is placed in the template.

If provided and neither -recipient nor -srvcert is given, the issuer DN is used as fallback recipient of outgoing CMP messages.

The argument must be formatted as /type0=value0/type1=value1/type2=.... For details see the description of the -subject option.

-days number

Number of days the new certificate is requested to be valid for, counting from the current time of the host. Also triggers the explicit request that the validity period starts from the current time (as seen by the host).

-reqexts name

Name of section in OpenSSL config file defining certificate request extensions. If the -csr option is present, these extensions augment the extensions contained the given PKCS#10 CSR, overriding any extensions with same OIDs.

-sans spec

One or more IP addresses, DNS names, or URIs separated by commas or whitespace (where in the latter case the whole argument must be enclosed in "...") to add as Subject Alternative Name(s) (SAN) certificate request extension. If the special element "critical" is given the SANs are flagged as critical. Cannot be used if any Subject Alternative Name extension is set via -reqexts.

-san_nodefault

When Subject Alternative Names are not given via -sans nor defined via -reqexts, they are copied by default from the reference certificate (see -oldcert). This can be disabled by giving the -san_nodefault option.

-policies name

Name of section in OpenSSL config file defining policies to be set as certificate request extension. This option cannot be used together with -policy_oids.

-policy_oids names

One or more OID(s), separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "...") to add as certificate policies request extension. This option cannot be used together with -policies.

-policy_oids_critical

Flag the policies given with -policy_oids as critical.

-popo number

Proof-of-possession (POPO) method to use for IR/CR/KUR; values: "-1"..<2> where "-1" = NONE, 0 = RAVERIFIED, 1 = SIGNATURE (default), 2 = KEYENC.

Note that a signature-based POPO can only be produced if a private key is provided via the -newkey or -key options.

-csr filename

PKCS#10 CSR in PEM or DER format containing a certificate request. With -cmd p10cr it is used directly in a legacy P10CR message.

When used with -cmd ir, cr, or kur, it is transformed into the respective regular CMP request. In this case, a private key must be provided (with -newkey or -key) for the proof of possession (unless -popo -1 or -popo 0 is used) and the respective public key is placed in the certification request (rather than taking over the public key contained in the PKCS#10 CSR).

PKCS#10 CSR input may also be used with -cmd rr to specify the certificate to be revoked via the included subject name and public key.

-out_trusted filenames|uris

Trusted certificate(s) to use for validating the newly enrolled certificate. During this verification, any certificate status checking is disabled.

Multiple sources may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). Each source may contain multiple certificates.

The certificate verification options -verify_hostname, -verify_ip, and -verify_email only affect the certificate verification enabled via this option.

-implicit_confirm

Request implicit confirmation of newly enrolled certificates.

-disable_confirm

Do not send certificate confirmation message for newly enrolled certificate without requesting implicit confirmation to cope with broken servers not supporting implicit confirmation correctly. WARNING: This leads to behavior violating RFC 4210.

-certout filename

The file where the newly enrolled certificate should be saved.

-chainout filename

The file where the chain of the newly enrolled certificate should be saved.

Certificate enrollment and revocation options

-oldcert filename|uri

The certificate to be updated (i.e., renewed or re-keyed) in Key Update Request (KUR) messages or to be revoked in Revocation Request (RR) messages. For KUR the certificate to be updated defaults to -cert, and the resulting certificate is called reference certificate. For RR the certificate to be revoked can also be specified using -csr.

The reference certificate, if any, is also used for deriving default subject DN and Subject Alternative Names and the default issuer entry in the requested certificate template of an IR/CR/KUR. Its public key is used as a fallback in the template of certification requests. Its subject is used as sender of outgoing messages if -cert is not given. Its issuer is used as default recipient in CMP message headers if neither -recipient, -srvcert, nor -issuer is given.

-revreason number

Set CRLReason to be included in revocation request (RR); values: 0..10 or "-1" for none (which is the default).

Reason numbers defined in RFC 5280 are:

   CRLReason ::= ENUMERATED {
        unspecified             (0),
        keyCompromise           (1),
        cACompromise            (2),
        affiliationChanged      (3),
        superseded              (4),
        cessationOfOperation    (5),
        certificateHold         (6),
        -- value 7 is not used
        removeFromCRL           (8),
        privilegeWithdrawn      (9),
        aACompromise           (10)
    }
    

Message transfer options

-server [http[s]://][userinfo@]host[:port][/path][?query][#fragment]

The DNS hostname or IP address and optionally port of the CMP server to connect to using HTTP(S). This option excludes -port and -use_mock_srv. It is ignored if -rspin is given with enough filename arguments.

The scheme "https" may be given only if the -tls_used option is used. In this case the default port is 443, else 80. The optional userinfo and fragment components are ignored. Any given query component is handled as part of the path component. If a path is included it provides the default value for the -path option.

-proxy [http[s]://][userinfo@]host[:port][/path][?query][#fragment]

The HTTP(S) proxy server to use for reaching the CMP server unless -no_proxy applies, see below. The proxy port defaults to 80 or 443 if the scheme is "https"; apart from that the optional "http://" or "https://" prefix is ignored (note that TLS may be selected by -tls_used), as well as any path, userinfo, and query, and fragment components. Defaults to the environment variable "http_proxy" if set, else "HTTP_PROXY" in case no TLS is used, otherwise "https_proxy" if set, else "HTTPS_PROXY". This option is ignored if -server is not given.

-no_proxy addresses

List of IP addresses and/or DNS names of servers not to use an HTTP(S) proxy for, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). Default is from the environment variable "no_proxy" if set, else "NO_PROXY". This option is ignored if -server is not given.

-recipient name

Distinguished Name (DN) to use in the recipient field of CMP request message headers, i.e., the CMP server (usually the addressed CA).

The recipient field in the header of a CMP message is mandatory. If not given explicitly the recipient is determined in the following order: the subject of the CMP server certificate given with the -srvcert option, the -issuer option, the issuer of the certificate given with the -oldcert option, the issuer of the CMP client certificate (-cert option), as far as any of those is present, else the NULL-DN as last resort.

The argument must be formatted as /type0=value0/type1=value1/type2=.... For details see the description of the -subject option.

-path remote_path

HTTP path at the CMP server (aka CMP alias) to use for POST requests. Defaults to any path given with -server, else "/".

-keep_alive value

If the given value is 0 then HTTP connections are not kept open after receiving a response, which is the default behavior for HTTP 1.0. If the value is 1 or 2 then persistent connections are requested. If the value is 2 then persistent connections are required, i.e., in case the server does not grant them an error occurs. The default value is 1, which means preferring to keep the connection open.

-msg_timeout seconds

Number of seconds a CMP request-response message round trip is allowed to take before a timeout error is returned. A value <= 0 means no limitation (waiting indefinitely). Default is to use the -total_timeout setting.

-total_timeout seconds

Maximum total number of seconds a transaction may take, including polling etc. A value <= 0 means no limitation (waiting indefinitely). Default is 0.

Server authentication options

-trusted filenames|uris

The certificate(s), typically of root CAs, the client shall use as trust anchors when validating signature-based protection of CMP response messages. This option is ignored if the -srvcert option is given as well. It provides more flexibility than -srvcert because the CMP protection certificate of the server is not pinned but may be any certificate from which a chain to one of the given trust anchors can be constructed.

If none of -trusted, -srvcert, and -secret is given, message validation errors will be thrown unless -unprotected_errors permits an exception.

Multiple sources may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). Each source may contain multiple certificates.

The certificate verification options -verify_hostname, -verify_ip, and -verify_email have no effect on the certificate verification enabled via this option.

-untrusted filenames|uris

Non-trusted intermediate CA certificate(s). Any extra certificates given with the -cert option are appended to it. All these certificates may be useful for cert path construction for the own CMP signer certificate (to include in the extraCerts field of request messages) and for the TLS client certificate (if TLS is enabled) as well as for chain building when validating server certificates (checking signature-based CMP message protection) and when validating newly enrolled certificates.

Multiple filenames or URLs may be given, separated by commas and/or whitespace. Each source may contain multiple certificates.

-srvcert filename|uri

The specific CMP server certificate to expect and directly trust (even if it is expired) when verifying signature-based protection of CMP response messages. This pins the accepted server and results in ignoring the -trusted option.

If set, the subject of the certificate is also used as default value for the recipient of CMP requests and as default value for the expected sender of CMP responses.

-expect_sender name

Distinguished Name (DN) expected in the sender field of incoming CMP messages. Defaults to the subject DN of the pinned -srvcert, if any.

This can be used to make sure that only a particular entity is accepted as CMP message signer, and attackers are not able to use arbitrary certificates of a trusted PKI hierarchy to fraudulently pose as a CMP server. Note that this option gives slightly more freedom than setting the -srvcert, which pins the server to the holder of a particular certificate, while the expected sender name will continue to match after updates of the server cert.

The argument must be formatted as /type0=value0/type1=value1/type2=.... For details see the description of the -subject option.

-ignore_keyusage

Ignore key usage restrictions in CMP signer certificates when validating signature-based protection of incoming CMP messages. By default, "digitalSignature" must be allowed by CMP signer certificates.

-unprotected_errors

Accept missing or invalid protection of negative responses from the server. This applies to the following message types and contents:

-extracertsout filename

The file where to save all certificates contained in the extraCerts field of the last received response message (except for pollRep and PKIConf).

-cacertsout filename

The file where to save any CA certificates contained in the caPubs field of the last received certificate response (i.e., IP, CP, or KUP) message.

Client authentication options

-ref value

Reference number/string/value to use as fallback senderKID; this is required if no sender name can be determined from the -cert or <-subject> options and is typically used when authenticating with pre-shared key (password-based MAC).

-secret arg

Provides the source of a secret value to use with MAC-based message protection. This takes precedence over the -cert and -key options. The secret is used for creating MAC-based protection of outgoing messages and for validating incoming messages that have MAC-based protection. The algorithm used by default is Password-Based Message Authentication Code (PBM) as defined in RFC 4210 section 5.1.3.1.

For more information about the format of arg see openssl-passphrase-options(1).

-cert filename|uri

The client's current CMP signer certificate. Requires the corresponding key to be given with -key.

The subject and the public key contained in this certificate serve as fallback values in the certificate template of IR/CR/KUR messages.

The subject of this certificate will be used as sender of outgoing CMP messages, while the subject of -oldcert or -subjectName may provide fallback values.

The issuer of this certificate is used as one of the recipient fallback values and as fallback issuer entry in the certificate template of IR/CR/KUR messages.

When performing signature-based message protection, this "protection certificate", also called "signer certificate", will be included first in the extraCerts field of outgoing messages and the signature is done with the corresponding key. In Initialization Request (IR) messages this can be used for authenticating using an external entity certificate as defined in appendix E.7 of RFC 4210.

For Key Update Request (KUR) messages this is also used as the certificate to be updated if the -oldcert option is not given.

If the file includes further certs, they are appended to the untrusted certs because they typically constitute the chain of the client certificate, which is included in the extraCerts field in signature-protected request messages.

-own_trusted filenames|uris

If this list of certificates is provided then the chain built for the client-side CMP signer certificate given with the -cert option is verified using the given certificates as trust anchors.

Multiple sources may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). Each source may contain multiple certificates.

The certificate verification options -verify_hostname, -verify_ip, and -verify_email have no effect on the certificate verification enabled via this option.

-key filename|uri

The corresponding private key file for the client's current certificate given in the -cert option. This will be used for signature-based message protection unless the -secret option indicating MAC-based protection or -unprotected_requests is given.

It is also used as a fallback for the -newkey option with IR/CR/KUR messages.

-keypass arg

Pass phrase source for the private key given with the -key option. Also used for -cert and -oldcert in case it is an encrypted PKCS#12 file. If not given here, the password will be prompted for if needed.

For more information about the format of arg see openssl-passphrase-options(1).

-digest name

Specifies name of supported digest to use in RFC 4210's MSG_SIG_ALG and as the one-way function (OWF) in "MSG_MAC_ALG". If applicable, this is used for message protection and proof-of-possession (POPO) signatures. To see the list of supported digests, use "openssl list -digest-commands". Defaults to "sha256".

-mac name

Specifies the name of the MAC algorithm in "MSG_MAC_ALG". To get the names of supported MAC algorithms use "openssl list -mac-algorithms" and possibly combine such a name with the name of a supported digest algorithm, e.g., hmacWithSHA256. Defaults to "hmac-sha1" as per RFC 4210.

-extracerts filenames|uris

Certificates to append in the extraCerts field when sending messages. They can be used as the default CMP signer certificate chain to include.

Multiple sources may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). Each source may contain multiple certificates.

-unprotected_requests

Send request messages without CMP-level protection.

Credentials format options

-certform PEM|DER

File format to use when saving a certificate to a file. Default value is PEM.

-keyform PEM|DER|P12|ENGINE

The format of the key input; unspecified by default. See "Format Options" in openssl(1) for details.

-otherpass arg

Pass phrase source for certificate given with the -trusted, -untrusted, -own_trusted, -srvcert, -out_trusted, -extracerts, -srv_trusted, -srv_untrusted, -rsp_extracerts, -rsp_capubs, -tls_extra, and -tls_trusted options. If not given here, the password will be prompted for if needed.

For more information about the format of arg see openssl-passphrase-options(1).

-engine id

See "Engine Options" in openssl(1). This option is deprecated.

As an alternative to using this combination:

    -engine {engineid} -key {keyid} -keyform ENGINE
    

... it's also possible to just give the key ID in URI form to -key, like this:

    -key org.openssl.engine:{engineid}:{keyid}
    

This applies to all options specifying keys: -key, -newkey, and -tls_key.

Provider options

-provider name

-provider-path path

-propquery propq

See "Provider Options" in openssl(1), provider(7), and property(7).

Random state options

-rand files, -writerand file

See "Random State Options" in openssl(1) for details.

TLS connection options

-tls_used

Enable using TLS (even when other TLS-related options are not set) for message exchange with CMP server via HTTP. This option is not supported with the -port option. It is ignored if the -server option is not given or -use_mock_srv is given or -rspin is given with enough filename arguments.

The following TLS-related options are ignored if -tls_used is not given or does not take effect.

-tls_cert filename|uri

Client's TLS certificate. If the source includes further certs they are used (along with -untrusted certs) for constructing the client cert chain provided to the TLS server.

-tls_key filename|uri

Private key for the client's TLS certificate.

-tls_keypass arg

Pass phrase source for client's private TLS key -tls_key. Also used for -tls_cert in case it is an encrypted PKCS#12 file. If not given here, the password will be prompted for if needed.

For more information about the format of arg see openssl-passphrase-options(1).

-tls_extra filenames|uris

Extra certificates to provide to TLS server during TLS handshake

-tls_trusted filenames|uris

Trusted certificate(s) to use for validating the TLS server certificate. This implies hostname validation.

Multiple sources may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). Each source may contain multiple certificates.

The certificate verification options -verify_hostname, -verify_ip, and -verify_email have no effect on the certificate verification enabled via this option.

-tls_host name

Address to be checked during hostname validation. This may be a DNS name or an IP address. If not given it defaults to the -server address.

Client-side debugging options

-batch

Do not interactively prompt for input, for instance when a password is needed. This can be useful for batch processing and testing.

-repeat number

Invoke the command the given positive number of times with the same parameters. Default is one invocation.

-reqin filenames

Take the sequence of CMP requests to send to the server from the given file(s) rather than from the sequence of requests produced internally.

This option is ignored if the -rspin option is given because in the latter case no requests are actually sent.

Multiple filenames may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "...").

The files are read as far as needed to complete the transaction and filenames have been provided. If more requests are needed, the remaining ones are taken from the items at the respective position in the sequence of requests produced internally.

The client needs to update the recipNonce field in the given requests (except for the first one) in order to satisfy the checks to be performed by the server. This causes re-protection (if protecting requests is required).

-reqin_new_tid

Use a fresh transactionID for CMP request messages read using -reqin, which causes their reprotection (if protecting requests is required). This may be needed in case the sequence of requests is reused and the CMP server complains that the transaction ID has already been used.

-reqout filenames

Save the sequence of CMP requests created by the client to the given file(s). These requests are not sent to the server if the -reqin option is used, too.

Multiple filenames may be given, separated by commas and/or whitespace.

Files are written as far as needed to save the transaction and filenames have been provided. If the transaction contains more requests, the remaining ones are not saved.

-rspin filenames

Process the sequence of CMP responses provided in the given file(s), not contacting any given server, as long as enough filenames are provided to complete the transaction.

Multiple filenames may be given, separated by commas and/or whitespace.

Any server specified via the -server or -use_mock_srv options is contacted only if more responses are needed to complete the transaction. In this case the transaction will fail unless the server has been prepared to continue the already started transaction.

-rspout filenames

Save the sequence of actually used CMP responses to the given file(s). These have been received from the server unless -rspin takes effect.

Multiple filenames may be given, separated by commas and/or whitespace.

Files are written as far as needed to save the responses contained in the transaction and filenames have been provided. If the transaction contains more responses, the remaining ones are not saved.

-use_mock_srv

Test the client using the internal CMP server mock-up at API level, bypassing socket-based transfer via HTTP. This excludes the -server and -port options.

Mock server options

-port number

Act as HTTP-based CMP server mock-up listening on the given port. This excludes the -server and -use_mock_srv options. The -rspin, -rspout, -reqin, and -reqout options so far are not supported in this mode.

-max_msgs number

Maximum number of CMP (request) messages the CMP HTTP server mock-up should handle, which must be nonnegative. The default value is 0, which means that no limit is imposed. In any case the server terminates on internal errors, but not when it detects a CMP-level error that it can successfully answer with an error message.

-srv_ref value

Reference value to use as senderKID of server in case no -srv_cert is given.

-srv_secret arg

Password source for server authentication with a pre-shared key (secret).

-srv_cert filename|uri

Certificate of the server.

-srv_key filename|uri

Private key used by the server for signing messages.

-srv_keypass arg

Server private key (and cert) file pass phrase source.

-srv_trusted filenames|uris

Trusted certificates for client authentication.

The certificate verification options -verify_hostname, -verify_ip, and -verify_email have no effect on the certificate verification enabled via this option.

-srv_untrusted filenames|uris

Intermediate CA certs that may be useful when validating client certificates.

-rsp_cert filename|uri

Certificate to be returned as mock enrollment result.

-rsp_extracerts filenames|uris

Extra certificates to be included in mock certification responses.

-rsp_capubs filenames|uris

CA certificates to be included in mock Initialization Response (IP) message.

-poll_count number

Number of times the client must poll before receiving a certificate.

-check_after number

The checkAfter value (number of seconds to wait) to include in poll response.

-grant_implicitconf

Grant implicit confirmation of newly enrolled certificate.

-pkistatus number

PKIStatus to be included in server response. Valid range is 0 (accepted) .. 6 (keyUpdateWarning).

-failure number

A single failure info bit number to be included in server response. Valid range is 0 (badAlg) .. 26 (duplicateCertReq).

-failurebits number Number representing failure bits to be included in server response. Valid range is 0 .. 2^27 - 1.

-statusstring arg

Text to be included as status string in server response.

-send_error

Force server to reply with error message.

-send_unprotected

Send response messages without CMP-level protection.

-send_unprot_err

In case of negative responses, server shall send unprotected error messages, certificate responses (IP/CP/KUP), and revocation responses (RP). WARNING: This setting leads to behavior violating RFC 4210.

-accept_unprotected

Accept missing or invalid protection of requests.

-accept_unprot_err

Accept unprotected error messages from client. So far this has no effect because the server does not accept any error messages.

-accept_raverified

Accept RAVERIFED as proof of possession (POPO).

Certificate verification options, for both CMP and TLS

-allow_proxy_certs, -attime, -no_check_time, -check_ss_sig, -crl_check, -crl_check_all, -explicit_policy, -extended_crl, -ignore_critical, -inhibit_any, -inhibit_map, -no_alt_chains, -partial_chain, -policy, -policy_check, -policy_print, -purpose, -suiteB_128, -suiteB_128_only, -suiteB_192, -trusted_first, -use_deltas, -auth_level, -verify_depth, -verify_email, -verify_hostname, -verify_ip, -verify_name, -x509_strict -issuer_checks

Set various options of certificate chain verification. See "Verification Options" in openssl-verification-options(1) for details.

The certificate verification options -verify_hostname, -verify_ip, and -verify_email only affect the certificate verification enabled via the -out_trusted option.

Simple examples using the default OpenSSL configuration file

This CMP client implementation comes with demonstrative CMP sections in the example configuration file openssl/apps/openssl.cnf, which can be used to interact conveniently with the Insta Demo CA.

In order to enroll an initial certificate from that CA it is sufficient to issue the following shell commands.

  export OPENSSL_CONF=/path/to/openssl/apps/openssl.cnf

  openssl genrsa -out insta.priv.pem
  openssl cmp -section insta

This should produce the file insta.cert.pem containing a new certificate for the private key held in insta.priv.pem. It can be viewed using, e.g.,

  openssl x509 -noout -text -in insta.cert.pem

In case the network setup requires using an HTTP proxy it may be given as usual via the environment variable http_proxy or via the -proxy option in the configuration file or the CMP command-line argument -proxy, for example

  -proxy http://192.168.1.1:8080

In the Insta Demo CA scenario both clients and the server may use the pre-shared secret insta and the reference value 3078 to authenticate to each other.

Alternatively, CMP messages may be protected in signature-based manner, where the trust anchor in this case is insta.ca.crt and the client may use any certificate already obtained from that CA, as specified in the [signature] section of the example configuration. This can be used in combination with the [insta] section simply by

  openssl cmp -section insta,signature

By default the CMP IR message type is used, yet CR works equally here. This may be specified directly at the command line:

  openssl cmp -section insta -cmd cr

or by referencing in addition the [cr] section of the example configuration:

  openssl cmp -section insta,cr

In order to update the enrolled certificate one may call

  openssl cmp -section insta,kur

using MAC-based protection with PBM or

  openssl cmp -section insta,kur,signature

using signature-based protection.

In a similar way any previously enrolled certificate may be revoked by

  openssl cmp -section insta,rr -trusted insta.ca.crt

or

  openssl cmp -section insta,rr,signature

Many more options can be given in the configuration file and/or on the command line. For instance, the -reqexts CLI option may refer to a section in the configuration file defining X.509 extensions to use in certificate requests, such as "v3_req" in openssl/apps/openssl.cnf:

  openssl cmp -section insta,cr -reqexts v3_req

Certificate enrollment

The following examples do not make use of a configuration file at first. They assume that a CMP server can be contacted on the local TCP port 80 and accepts requests under the alias /pkix/.

For enrolling its very first certificate the client generates a client key and sends an initial request message to the local CMP server using a pre-shared secret key for mutual authentication. In this example the client does not have the CA certificate yet, so we specify the name of the CA with the -recipient option and save any CA certificates that we may receive in the "capubs.pem" file.

In below command line usage examples the "\" at line ends is used just for formatting; each of the command invocations should be on a single line.

  openssl genrsa -out cl_key.pem
  openssl cmp -cmd ir -server 127.0.0.1:80/pkix/ -recipient "/CN=CMPserver" \
    -ref 1234 -secret pass:1234-5678 \
    -newkey cl_key.pem -subject "/CN=MyName" \
    -cacertsout capubs.pem -certout cl_cert.pem

Certificate update

Then, when the client certificate and its related key pair needs to be updated, the client can send a key update request taking the certs in "capubs.pem" as trusted for authenticating the server and using the previous cert and key for its own authentication. Then it can start using the new cert and key.

  openssl genrsa -out cl_key_new.pem
  openssl cmp -cmd kur -server 127.0.0.1:80/pkix/ \
    -trusted capubs.pem \
    -cert cl_cert.pem -key cl_key.pem \
    -newkey cl_key_new.pem -certout cl_cert.pem
  cp cl_key_new.pem cl_key.pem

This command sequence can be repeated as often as needed.

Requesting information from CMP server

Requesting "all relevant information" with an empty General Message. This prints information about all received ITAV infoTypes to stdout.

  openssl cmp -cmd genm -server 127.0.0.1/pkix/ -recipient "/CN=CMPserver" \
    -ref 1234 -secret pass:1234-5678

Using a custom configuration file

For CMP client invocations, in particular for certificate enrollment, usually many parameters need to be set, which is tedious and error-prone to do on the command line. Therefore, the client offers the possibility to read options from sections of the OpenSSL config file, usually called openssl.cnf. The values found there can still be extended and even overridden by any subsequently loaded sections and on the command line.

After including in the configuration file the following sections:

  [cmp]
  server = 127.0.0.1
  path = pkix/
  trusted = capubs.pem
  cert = cl_cert.pem
  key = cl_key.pem
  newkey = cl_key.pem
  certout = cl_cert.pem
  [init]
  recipient = "/CN=CMPserver"
  trusted =
  cert =
  key =
  ref = 1234
  secret = pass:1234-5678-1234-567
  subject = "/CN=MyName"
  cacertsout = capubs.pem

the above enrollment transactions reduce to

  openssl cmp -section cmp,init
  openssl cmp -cmd kur -newkey cl_key_new.pem

and the above transaction using a general message reduces to

  openssl cmp -section cmp,init -cmd genm