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openssl-cmp

Certificate Management Protocol (CMP, RFC 4210) application

openssl cmp [-help] [-config filename] [-section names] [-verbosity level]

Generic message options:

[-cmd ir|cr|kur|p10cr|rr|genm] [-infotype name] [-geninfo OID:int:N]

Certificate enrollment options:

[-newkey filename|uri] [-newkeypass arg] [-subject name] [-issuer name] [-days number] [-reqexts name] [-sans spec] [-san_nodefault] [-policies name] [-policy_oids names] [-policy_oids_critical] [-popo number] [-csr filename] [-out_trusted filenames|uris] [-implicit_confirm] [-disable_confirm] [-certout filename] [-chainout filename]

Certificate enrollment and revocation options:

[-oldcert filename|uri] [-revreason number]

Message transfer options:

[-server [http[s]://][userinfo@]host[:port][/path][?query][#fragment]] [-proxy [http[s]://][userinfo@]host[:port][/path][?query][#fragment]] [-no_proxy addresses] [-recipient name] [-path remote_path] [-keep_alive value] [-msg_timeout seconds] [-total_timeout seconds]

Server authentication options:

[-trusted filenames|uris] [-untrusted filenames|uris] [-srvcert filename|uri] [-expect_sender name] [-ignore_keyusage] [-unprotected_errors] [-extracertsout filename] [-cacertsout filename]

Client authentication and protection options:

[-ref value] [-secret arg] [-cert filename|uri] [-own_trusted filenames|uris] [-key filename|uri] [-keypass arg] [-digest name] [-mac name] [-extracerts filenames|uris] [-unprotected_requests]

Credentials format options:

[-certform PEM|DER] [-keyform PEM|DER|P12|ENGINE] [-otherpass arg] [-engine id] [-provider name] [-provider-path path] [-propquery propq]

Random state options:

[-rand files] [-writerand file]

TLS connection options:

[-tls_used] [-tls_cert filename|uri] [-tls_key filename|uri] [-tls_keypass arg] [-tls_extra filenames|uris] [-tls_trusted filenames|uris] [-tls_host name]

Client-side debugging options:

[-batch] [-repeat number] [-reqin filenames] [-reqin_new_tid] [-reqout filenames] [-rspin filenames] [-rspout filenames] [-use_mock_srv]

Mock server options:

[-port number] [-max_msgs number] [-srv_ref value] [-srv_secret arg] [-srv_cert filename|uri] [-srv_key filename|uri] [-srv_keypass arg] [-srv_trusted filenames|uris] [-srv_untrusted filenames|uris] [-rsp_cert filename|uri] [-rsp_extracerts filenames|uris] [-rsp_capubs filenames|uris] [-poll_count number] [-check_after number] [-grant_implicitconf] [-pkistatus number] [-failure number] [-failurebits number] [-statusstring arg] [-send_error] [-send_unprotected] [-send_unprot_err] [-accept_unprotected] [-accept_unprot_err] [-accept_raverified]

Certificate verification options, for both CMP and TLS:

[-allow_proxy_certs] [-attime timestamp] [-no_check_time] [-check_ss_sig] [-crl_check] [-crl_check_all] [-explicit_policy] [-extended_crl] [-ignore_critical] [-inhibit_any] [-inhibit_map] [-partial_chain] [-policy arg] [-policy_check] [-policy_print] [-purpose purpose] [-suiteB_128] [-suiteB_128_only] [-suiteB_192] [-trusted_first] [-no_alt_chains] [-use_deltas] [-auth_level num] [-verify_depth num] [-verify_email email] [-verify_hostname hostname] [-verify_ip ip] [-verify_name name] [-x509_strict] [-issuer_checks]

The cmp command is a client implementation for the Certificate Management Protocol (CMP) as defined in RFC4210. It can be used to request certificates from a CA server, update their certificates, request certificates to be revoked, and perform other types of CMP requests.

Display a summary of all options
Configuration file to use. An empty string "" means none. Default filename is from the environment variable "OPENSSL_CONF".
Section(s) to use within config file defining CMP options. An empty string "" means no specific section. Default is "cmp".

Multiple section names may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). Contents of sections named later may override contents of sections named before. In any case, as usual, the "[default]" section and finally the unnamed section (as far as present) can provide per-option fallback values.

Level of verbosity for logging, error output, etc. 0 = EMERG, 1 = ALERT, 2 = CRIT, 3 = ERR, 4 = WARN, 5 = NOTE, 6 = INFO, 7 = DEBUG, 8 = TRACE. Defaults to 6 = INFO.

CMP command to execute. Currently implemented commands are:

ir requests initialization of an end entity into a PKI hierarchy by issuing a first certificate.

cr requests issuing an additional certificate for an end entity already initialized to the PKI hierarchy.

p10cr requests issuing an additional certificate similarly to cr but using legacy PKCS#10 CSR format.

kur requests a (key) update for an existing certificate.

rr requests revocation of an existing certificate.

genm requests information using a General Message, where optionally included InfoTypeAndValues may be used to state which info is of interest. Upon receipt of the General Response, information about all received ITAV infoTypes is printed to stdout.

Set InfoType name to use for requesting specific info in genm, e.g., "signKeyPairTypes".
generalInfo integer values to place in request PKIHeader with given OID, e.g., "1.2.3.4:int:56789".

The source of the private or public key for the certificate requested in Initialization Request (IR), Certification Request(CR), or Key Update Request (KUR). 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.
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).

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

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"

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.

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).
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.
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.
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.
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.
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.
Flag the policies given with -policy_oids as critical.
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.

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. It may also be used with -cmd rr to specify the certificate to be revoked via the included subject name and public key.
Trusted certificate(s) to use for validating the newly enrolled certificate.

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.

Request implicit confirmation of newly enrolled certificates.
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.
The file where the newly enrolled certificate should be saved.
The file where the chain of the newly enrolled certificate should be saved.

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 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.

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)
    }

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

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.

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.
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.
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.

HTTP path at the CMP server (aka CMP alias) to use for POST requests. Defaults to any path given with -server, else "/".
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.
Number of seconds (or 0 for infinite) a CMP request-response message round trip is allowed to take before a timeout error is returned. Default is to use the -total_timeout setting.
Maximum number seconds an overall enrollment transaction may take, including attempts polling for certificates on "waiting" PKIStatus. Default is 0 (infinite).

When validating signature-based protection of CMP response messages, these are the CA certificate(s) to trust while checking certificate chains during CMP server authentication. This option gives more flexibility than the -srvcert option because the server-side CMP signer certificate is not pinned but may be any certificate for which a chain to one of the given trusted certificates can be constructed.

If no -trusted, -srvcert, and -secret option is given then protected response messages from the server are not authenticated.

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.

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 CMP client certificate (to include in the extraCerts field of outgoing messages) and for the TLS client certificate (if TLS is enabled) as well as for chain building when validating the CMP server certificate (checking signature-based CMP message protection) and when validating newly enrolled certificates.

Multiple sources may be given, separated by commas and/or whitespace. Each file may contain multiple certificates.

The specific CMP server certificate to expect and directly trust (even if it is expired) when validating signature-based protection of CMP response messages. May be set alternatively to the -trusted option to pin the accepted server.

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 incoming CMP messages.

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 key usage restrictions in CMP signer certificates when validating signature-based protection of incoming CMP messages, else "digitalSignature" must be allowed for signer certificate.
Accept missing or invalid protection of negative responses from the server. This applies to the following message types and contents:
  • error messages
  • negative certificate responses (IP/CP/KUP)
  • negative revocation responses (RP)
  • negative PKIConf messages

WARNING: This setting leads to unspecified behavior and it is meant exclusively to allow interoperability with server implementations violating RFC 4210, e.g.:

  • section 5.1.3.1 allows exceptions from protecting only for special cases: "There MAY be cases in which the PKIProtection BIT STRING is deliberately not used to protect a message [...] because other protection, external to PKIX, will be applied instead."
  • section 5.3.21 is clear on ErrMsgContent: "The CA MUST always sign it with a signature key."
  • appendix D.4 shows PKIConf message having protection
The file where to save all certificates contained in the extraCerts field of the last received response message (except for pollRep and PKIConf).
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.

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).
Prefer PBM-based message protection with given source of a secret value. The secret is used for creating PBM-based protection of outgoing messages and (as far as needed) for validating PBM-based protection of incoming messages. PBM stands for Password-Based Message Authentication Code. This takes precedence over the -cert and -key options.

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

The client's current CMP signer certificate. Requires the corresponding key to be given with -key. 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. When using signature-based message protection, this "protection 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.
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.

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 PBM or -unprotected_requests is given.
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).

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".
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.
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.

Send messages without CMP-level protection.

File format to use when saving a certificate to a file. Default value is PEM.
The format of the key input; unspecified by default. See "Format Options" in openssl(1) for details.
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).

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.

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

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

TLS connection options

Enable using TLS (even when other TLS_related options are not set) when connecting to CMP server via HTTP. This option is not supported with the -port option and is ignored with the -use_mock_srv and -rspin options or if the -server option is not given.
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.
Private key for the client's TLS certificate.
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).

Extra certificates to provide to TLS server during TLS handshake
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.

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.

Do not interactively prompt for input, for instance when a password is needed. This can be useful for batch processing and testing.
Invoke the command the given positive number of times with the same parameters. Default is one invocation.
Take sequence of CMP requests from file(s).

Multiple filenames may be given, separated by commas and/or whitespace (where in the latter case the whole argument must be enclosed in "..."). As many files are read as needed for a complete transaction.

Use a fresh transactionID for CMP request messages read using -reqin, which requires re-protecting them as far as they were protected before. 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.
Save sequence of CMP requests to file(s).

Multiple filenames may be given, separated by commas and/or whitespace. As many files are written as needed to store the complete transaction.

Process sequence of CMP responses provided in file(s), skipping server. This excludes -server, -port, and -use_mock_srv.

Multiple filenames may be given, separated by commas and/or whitespace. As many files are read as needed for the complete transaction.

Save sequence of CMP responses to file(s).

Multiple filenames may be given, separated by commas and/or whitespace. As many files are written as needed to store the complete transaction.

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

Act as HTTP-based CMP server mock-up listening on the given port. This excludes -server, -rspin, and -use_mock_srv.
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.
Reference value to use as senderKID of server in case no -srv_cert is given.
Password source for server authentication with a pre-shared key (secret).
Certificate of the server.
Private key used by the server for signing messages.
Server private key (and cert) file pass phrase source.
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.

Intermediate CA certs that may be useful when validating client certificates.
Certificate to be returned as mock enrollment result.
Extra certificates to be included in mock certification responses.
CA certificates to be included in mock Initialization Response (IP) message.
Number of times the client must poll before receiving a certificate.
The checkAfter value (number of seconds to wait) to include in poll response.
Grant implicit confirmation of newly enrolled certificate.
PKIStatus to be included in server response. Valid range is 0 (accepted) .. 6 (keyUpdateWarning).
A single failure info bit number to be included in server response. Valid range is 0 (badAlg) .. 26 (duplicateCertReq).
Text to be included as status string in server response.
Force server to reply with error message.
Send response messages without CMP-level protection.
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 missing or invalid protection of requests.
Accept unprotected error messages from client.
Accept RAVERIFED as proof-of-possession (POPO).

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.

When setting up CMP configurations and experimenting with enrollment options typically various errors occur until the configuration is correct and complete. When the CMP server reports an error the client will by default check the protection of the CMP response message. Yet some CMP services tend not to protect negative responses. In this case the client will reject them, and thus their contents are not shown although they usually contain hints that would be helpful for diagnostics. For assisting in such cases the CMP client offers a workaround via the -unprotected_errors option, which allows accepting such negative messages.

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 with PBM-based protection 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

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

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 repated as often as needed.

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

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

openssl-genrsa(1), openssl-ecparam(1), openssl-list(1), openssl-req(1), openssl-x509(1), x509v3_config(5)

The cmp application was added in OpenSSL 3.0.

The -engine option was deprecated in OpenSSL 3.0.

Copyright 2007-2022 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.