OPENSSL-CMP(1ossl)

📦
version 3.5.9 · 8 versions
, in alpine 3.23, alpine 3.24

🌈 💅 OPENSSL-CMP(1ossl) 💅 🌈

🎀 NAME 🎀

openssl-cmp — Certificate Management Protocol (CMP, RFCs 9810 and 9811) application

✨ SYNOPSIS ✨

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

Generic message options:

[-cmd ir|cr|kur|p10cr|rr|genm] [-infotype name] [-profile name]
[-geninfo values] [-template filename] [-keyspec filename]

Certificate enrollment options:

[-newkey filename|uri] [-newkeypass arg] [-centralkeygen [-newkeyout
filename] [-subject 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] [-issuer name] [-serial number] [-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] [-no_cache_extracerts] [-srvcertout filename]
[-extracertsout filename] [-cacertsout filename] [-oldwithold filename]
[-newwithnew filename] [-newwithold filename] [-oldwithnew filename]
[-crlcert filename] [-oldcrl filename] [-crlout 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] [-crlform PEM|DER] [-keyform PEM|DER|P12|ENGINE]
[-otherpass arg] [-engine id] [-provider name] [-provider-path path]
[-provparam [name:]key=value] [-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] [-reqout_only filename] [-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] [-ref_cert
filename|uri] [-rsp_cert filename|uri] [-rsp_key filename|uri]
[-rsp_keypass filename|uri] [-rsp_crl filename|uri] [-rsp_extracerts
filenames|uris] [-rsp_capubs filenames|uris] [-rsp_newwithnew
filename|uri] [-rsp_newwithold filename|uri] [-rsp_oldwithnew
filename|uri] [-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]

💖 DESCRIPTION 💖

Okay bestie, so the cmp command is a client implementation for the Certificate Management Protocol (CMP) as defined in RFCs 9810 and its HTTP(S) transfer as defined in RFC 9811. 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. It’s giving “I have things to do with a CA and I’m doing them on purpose.” 💅

🌟 OPTIONS 🌟

  • -help — Displays a summary of all options. Iconic little cheat sheet moment.
  • -config filename — Configuration file to use. An empty string "" means none. Default filename is from the environment variable OPENSSL_CONF. No cap, that env var is the plug.
  • -section names — 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. It’s giving layered outfit energy: later layers can serve looks over earlier ones, but the fallback pieces still show up if needed. 🫶

  • -verbosity level — 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. Set it higher if you want the tea; lower if you want it quiet.

💌 Generic message options 💌

  • -cmd ir|cr|kur|p10cr|rr|genm — CMP command to execute. Currently implemented commands are:
    • ir — Initialization Request: requests initialization of an end entity into a PKI hierarchy by issuing a first certificate.
    • cr — Certificate Request: requests issuing an additional certificate for an end entity already initialized to the PKI hierarchy.
    • p10cr — PKCS#10 Certification Request (for legacy support): requests issuing an additional certificate similarly to cr but using legacy PKCS#10 CSR format.
    • kur — Key Update Request: requests a (key) update for an existing certificate.
    • rr — Revocation Request: requests revocation of an existing certificate.
    • genm — General Message: 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.

Main character energy is picking the right one for the task, bestie. 💅

  • -infotype name — Set InfoType name to use for requesting specific info in genm, e.g., "signKeyPairTypes". There is specific support for "caCerts", "rootCaCert", "certReqTemplate", and "crlStatusList" (CRL update retrieval). Iykyk, those special ones are the VIP list.
  • -profile name — Name of a certificate profile to place in the PKIHeader generalInfo field of request messages. It’s literally the vibe label for the request.
  • -geninfo values — A comma-separated list of InfoTypeAndValue to place in the generalInfo field of the PKIHeader of requests messages. Each InfoTypeAndValue gives an OID and an integer or string value of the form OID:int:number or OID:str:text, e.g., '1.2.3.4:int:56789,id-kp:str:name'. Tiny structured info drop, but make it fashion. 🎀
  • -template filename — The file to save any CRMF certTemplate in DER format received in a genp message with id-it-certReqTemplate. Save the template, bestie.
  • -keyspec filename — It is optional and used to specify the file to save any keySpec if present in a genp message with id-it-keyGenParameters.

Note: any keySpec field contents received are logged as INFO. So yes, the receipts are in the logs. 💀

🍓 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. So bestie, this is not a “public key only and pray” situation unless the options say so. 🔥

  • -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). Very “read the docs, bestie” of it.

  • -centralkeygen — Request central key generation for certificate enrollment. This applies to -cmd ir|cr|kur|p10cr. Central keygen said “I’ll handle the keys, you handle the vibe.” 👑
  • -newkeyout filename — File to save centrally generated private key, in PEM format. That’s the key drop location.
  • -subject name — X.509 Distinguished Name (DN) to use as subject field in the requested certificate template in IR/CR/KUR messages. 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 of -cert, -oldcert, or -csr 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

It’s giving “structured name, but make it slashy.” 🌸

  • -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). Time math, but make it intentional.
  • -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. Extension glow-up with override privileges. ✨
  • -sans spec — One or more IP addresses, email 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. SANs are the extra names on the certificate’s guest list, and critical is the “do not ignore this” sticker. 🦋
  • -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. So if you don’t want the reference cert’s SANs copied over, say less and use this flag. 💜
  • -policies name — the name of a section in the OpenSSL config file that defines the policies you want dropped in as a certificate request extension ✨. Heads up though: this one cannot be used together with -policy_oids — it's one or the other, bestie, no cap.
  • -policy_oids names — one or more OID(s) to add as the certificate policies request extension, separated by commas and/or whitespace (and for the whitespace case the whole argument must be wrapped in "..."). Also a hard no on combining with -policies 🚫.
  • -policy_oids_critical — flags the policies you gave with -policy_oids as critical. That's it, that's the whole job 💅.
  • -popo number — which Proof-of-possession (POPO) method to use for IR/CR/KUR. The values are: -1..<2> where -1 = NONE, which implies central key generation, 0 = RAVERIFIED, 1 = SIGNATURE (this is the default), and 2 = KEYENC.
Lowkey important: a signature-based POPO can only be produced if a private key is provided via the -newkey or -key options. No key, no sig, periodt.
  • -csr filename — a PKCS#10 CSR in PEM or DER format containing a certificate request. With -cmd p10cr it's used directly in a legacy P10CR message 🎀.

When you use it with -cmd ir, cr, or kur, it gets transformed into the respective regular CMP request. In that 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 🦋. Its subject is used as fallback sender in CMP message headers if -cert and -oldcert are not given.

  • -out_trusted filenames|uris — the 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, iykyk.

  • -implicit_confirm — request implicit confirmation of newly enrolled certificates 🙈.
  • -disable_confirm — do not send the certificate confirmation message for a newly enrolled certificate without requesting implicit confirmation, so you can cope with broken servers that don't support implicit confirmation correctly.
⚠️ WARNING: This leads to behavior violating RFC 9810. Like, actually forbidden behavior, bestie. Proceed with awareness.
  • -certout filename — the file where any newly enrolled certificate should be saved 🎀.
  • -chainout filename — the file where the chain of any newly enrolled certificate should be saved. This chain excludes the leaf certificate, i.e., the newly enrolled certificate. Also the trust anchor (the root certificate) is not included.

If the -certout option is given too, with an equal filename argument, then the file produced contains both outputs concatenated: the newly enrolled certificate followed by its chain. Two-for-one slay ✨.

💜 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 the reference certificate. For RR the certificate to be revoked can also be specified using -csr. Note that -oldcert and -csr are ignored if -issuer and -serial is provided.

The reference certificate, if any, is also used for deriving default subject DN and Subject Alternative Names, plus 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. And its issuer is used as default recipient in CMP message headers if neither -recipient, -srvcert, nor -issuer is given. It's giving fallback queen 👑.

  • -issuer name — an X.509 Distinguished Name (DN) to place as the issuer field in the requested certificate template in IR/CR/KUR/RR messages. 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 🎀.

  • -serial number — specifies the serial number of the certificate to be revoked in a revocation request. The serial number can be decimal or hex (if preceded by "0x") ✨.
  • -revreason number — sets the CRLReason to be included in the revocation request (RR). Values: 0..10 or -1 for none (which is the default).

The 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)
 }

(Yes, 7 is literally just vibing in the void — not used, don't come for me 💀.)

🌈 Message transfer options 🌈

  • -server [http[s]://][userinfo@]host[:port][/path][?query][#fragment] — the host domain name or IP address, and optionally port, of the CMP server to connect to using HTTP(S) 🫶. The IP address may be for v4 or v6, such as 127.0.0.1 or "[::1]" for localhost. If the host string is an IPv6 address, it must be enclosed in "[" and "]".

This option excludes -port and -use_mock_srv. It is ignored if -rspin is given with enough filename arguments.

If the scheme "https" is given, the -tls_used option is implied. When TLS is used, the default port is 443, otherwise 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) 🦋. If the host string is an IPv6 address, it must be enclosed in "[" and "]". 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 using TLS may be required by -tls_used or -server with the prefix "https"), 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 — it can't do anything on its own, bestie 🙈.
  • -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, fr fr. 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 — the 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 closed after each response (which would be the default behavior of HTTP 1.0) even if a CMP transaction needs more than one round trip. If the value is 1 or 2, then for each transaction a persistent connection is requested. If the value is 2, then a persistent connection is required, i.e., an error occurs if the server does not grant it 💀. The default value is 1, which means preferring to keep the connection open — main character energy, honestly.
  • -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 — the non-trusted intermediate CA certificate(s), bestie 💅. Any extra certs you drop in with the -cert option get appended onto it, so it's giving "yes and". 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 used) as well as for chain building when validating server certificates (checking signature-based CMP message protection) and when validating newly enrolled certificates.

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. Slay, multiple sources, okay? ✨

  • -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. Like, it's the main character and everyone else is a background extra.

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. So it's like trusting the person, not the outfit 💜.

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. This option applies to both CMP clients and the mock server. It's giving chaotic-neutral, use wisely.
  • -unprotected_errors — 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 9810, 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
  • -no_cache_extracerts — do not cache certificates in the extraCerts field of CMP messages received. By default, they are kept as they may be helpful for validating further messages. This option applies to both CMP clients and the mock server. 🪩

In any case, after successfully validating an incoming message, its protection certificate (if any) is cached for reuse with validation of subsequent messages. This is done not only for efficiency but also to eliminate the need for the sender to include its certificate and related chain in the extraCerts field of subsequent messages of the same transaction. Iconic behaviour honestly 👑

  • -srvcertout filename — the file where to save the successfully validated certificate, if any, that the CMP server used for signature-based response message protection. If there is no such certificate, typically because the protection was MAC-based, this is indicated by deleting the file (if it existed). Not me deleting your file to send a message 💀
  • -extracertsout filename — the file where to save the list of certificates contained in the extraCerts field of the last received response message that is not a pollRep nor PKIConf.
  • -cacertsout filename — the file where to save the list of CA certificates contained in the caPubs field if a positive certificate response (i.e., IP, CP, or KUP) message was received or contained in a general response (genp) message with infoType "caCerts". 🦋
  • -oldwithold filename — the root CA certificate to include in a genm request of infoType "rootCaCert". If present and the optional oldWithNew certificate is received, it is verified using the newWithNew certificate as the (only) trust anchor.
  • -newwithnew filename — this option must be provided when -infotype rootCaCert is given. It specifies the file to save the newWithNew certificate received in a genp message of type "rootCaKeyUpdate". If on success no such cert was received, this file (if present) is deleted to indicate that the requested root CA certificate update is not available. 🧚

Any received newWithNew certificate is verified using any received newWithOld certificate as untrusted intermediate certificate and the certificate provided with -oldwithold as the (only) trust anchor, or if not provided, using the certificates given with the -trusted option.

WARNING: The newWithNew certificate is meant to be a certificate that will be trusted. The trust placed in it cannot be stronger than the trust placed in the -oldwithold certificate if present, otherwise it cannot be stronger than the weakest trust placed in any of the -trusted certificates. Fr fr, trust is not transitive like that 💔
  • -newwithold filename — the file to save any newWithOld certificate received in a genp message of infoType "rootCaKeyUpdate". If on success no such cert was received, this is indicated by deleting the file.
  • -oldwithnew filename — the file to save any oldWithNew certificate received in a genp message of infoType "rootCaKeyUpdate". If on success no such cert was received, this is indicated by deleting the file. (Yes bestie, same energy, different field 🌸)
  • -crlcert filename — certificate to derive CRL issuer data for the source field when obtaining a CRL in a genm request with infoType "crlStatusList". Any available distribution point name is preferred over issuer names. 💅
  • -oldcrl filename — the CRL to obtain an update for in a genm request with infoType "crlStatusList". Unless the -crlcert option is provided as well, the given CRL is used for deriving CRL issuer data for the source field. Any available distribution point name is preferred over issuer names. If the CRL contains a thisUpdate field, its value is copied to the request. 🍓
  • -crlout filename — the file to save any CRL received in a genp message of infoType "crls". If on success no such CRL was received, this is indicated by deleting the file.

🔐 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). Iykyk 🔑
  • -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 9810 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 D.7 of RFC 9810.

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. She's the whole package, periodt 💖

  • -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. Lowkey they just don't apply here, ngl.

  • -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. No cap, it'll just ask you 🙈

For all the deets on what arg looks like, peep openssl-passphrase-options(1). 💅

  • -digest name — picks the supported digest name to use in RFC 9810's MSG_SIG_ALG and as the one-way function (OWF) in MSG_MAC_ALG. If it applies, this is used for message protection and proof-of-possession (POPO) signatures. Wanna see the supported digests? Run openssl list -digest-commands. Defaults to sha256. ✨
  • -mac name — names the MAC algorithm in MSG_MAC_ALG. To get the names of supported MAC algorithms, use openssl list -mac-algorithms, and you can possibly combine such a name with the name of a supported digest algorithm, e.g., hmacWithSHA256. Defaults to hmac-sha1, for backward compatibility with 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. 💖
  • -crlform PEM|DER — file format to use when saving a CRL to a file. Default value is DER. DER format is preferred because it enables more efficient storage of large CRLs. 🔥
  • -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, -crlcert, -out_trusted, -extracerts, -srv_trusted, -srv_untrusted, -ref_cert, -rsp_extracerts, -rsp_capubs, -rsp_newwithnew, -rsp_newwithold, -rsp_oldwithnew, -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

…you can also 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 ⭐

🌸 Random state options 🌸

  • -rand files — see "Random State Options" in openssl(1) for details. 💖
  • -writerand file — same "Random State Options" in openssl(1), bestie. 🦋

🔥 TLS connection options 🔥

  • -tls_used — make the CMP client use TLS (regardless if other TLS-related options are set) for message exchange with the server via HTTP. This option is not supported with the -port option. It is implied if the -server option is given with the scheme https. 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 is not used. 💀

  • -tls_cert filename|uri — client's TLS certificate to use for authenticating to the TLS server. 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 the TLS server during 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 options for debugging and offline scenarios 🦋

  • -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 useful for supporting offline scenarios where the certificate request (or any other CMP request) is produced beforehand and sent out later.

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

Note that in any case the client produces internally its sequence of CMP request messages. Thus, all options required for doing this (such as -cmd and all options providing the required parameters) need to be given also when the -reqin option is present.

If the -reqin option is given for a certificate request and no -newkey, -key, -oldcert, or -csr option is given, a fallback public key is taken from the request message file (if it is included in the certificate template).

Hint: In case the -reqin option is given for a certificate request, there are situations where the client has access to the public key to be certified but not to the private key that by default will be needed for proof of possession. In this case the POPO is not actually needed (because the internally produced certificate request message will not be sent), and its generation can be disabled using the options -popo -1 or -popo 0.

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. 🎀

  • -reqout_only filename — save the first CMP requests created by the client to the given file and exit. Any options related to CMP servers and their responses are ignored. This option does not combine with the -port option.

This option is useful for supporting offline scenarios where the certificate request (or any other CMP request) is produced beforehand and sent out later. ✨

  • -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 local port. The client may address the server via, e.g., 127.0.0.1 or [::1]. This option 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 — the server's own certificate 💅
  • -srv_key filename|uri — the private key the server signs its messages with, bestie 🔑
  • -srv_keypass arg — where to get the pass phrase for the server's private key (and cert) file
  • -srv_trusted filenames|uris — trusted certs used to authenticate clients.
Ok so heads up 🫶: the verification options -verify_hostname, -verify_ip, and -verify_email do not do anything to the verification that this option turns on.
  • -srv_untrusted filenames|uris — intermediate CA certs that might come in handy when validating client certs
  • -ref_cert filename|uri — the certificate that's expected for RR messages and for any oldCertID in KUR messages 🌸
  • -rsp_cert filename|uri — certificate that gets returned as the mock enrollment result
  • -rsp_key filename|uri — private key returned as the central key generation result
  • -rsp_keypass arg — pass phrase source for rsp_cert and rsp_key
  • -rsp_crl filename|uri — CRL returned in genp of type "crls"
  • -rsp_extracerts filenames|uris — extra certs to shove into mock certification responses ✨
  • -rsp_capubs filenames|uris — CA certs included in the mock Initialization Response (IP) message
  • -rsp_newwithnew filename|uri — cert returned in the newWithNew field of genp of type rootCaKeyUpdate
  • -rsp_newwithold filename|uri — cert returned in the newWithOld field of genp of type rootCaKeyUpdate
  • -rsp_oldwithnew filename|uri — cert returned in the oldWithNew field of genp of type rootCaKeyUpdate
  • -poll_count number — how many times the client has to poll before it finally gets a certificate 😭 the girlies hate waiting
  • -check_after number — the checkAfter value (number of seconds to wait, fr) included in the poll response
  • -grant_implicitconf — grant implicit confirmation of the newly enrolled certificate ✅
  • -pkistatus number — PKIStatus included in the server response. Valid range is 0 (accepted) .. 6 (keyUpdateWarning).
  • -failure number — a single failure info bit number to include in the server response. Valid range is 0 (badAlg) .. 26 (duplicateCertReq).
  • -failurebits number — number representing failure bits to include in the server response. Valid range is 0 .. 2^27 - 1.
  • -statusstring arg — the text that goes in as the status string in the server response
  • -send_error — force the server to reply with an error message 💀
  • -send_unprotected — send response messages without CMP-level protection
  • -send_unprot_err — in case of negative responses, the server shall send unprotected error messages, certificate responses (IP/CP/KUP), and revocation responses (RP).
⚠️ WARNING ⚠️ this setting leads to behavior that violates RFC 9810. Like. It's literally in the manpage. Don't come for me.
  • -accept_unprotected — accept missing or invalid protection of requests 🙈
  • -accept_unprot_err — accept unprotected error messages from the client. Ngl this currently has no effect, because the server doesn't accept any error messages at all.
  • -accept_raverified — accept RAVERIFIED 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 — these set various options for certificate chain verification, periodt. Go read "Verification Options" in openssl-verification-options(1) for all the deets 👑
Ok important one 🫶: the certificate verification options -verify_hostname, -verify_ip, and -verify_email only affect the certificate verification that's enabled via the -out_trusted option. That's it. That's the whole vibe check.

📝 NOTES 📝

So here's the situation, bestie. When a client gets CA certificates from a CMP server and it's actually going to trust them — like, say, via the "caPubs" field of a certificate response, or by using general messages with infoType "caCerts" or "rootCaCert" — then authenticating that CMP server is especially critical 👀 like, main character levels of critical. So you gotta take special care setting up server authentication: use -trusted and the related options for certificate-based authentication, or -secret for MAC-based protection. And if the authentication is certificate-based, you should use the -srvcertout option to get the validated server certificate and do an authorization check based on it. That's the move ✨

When you're setting up CMP configurations and experimenting with enrollment options, you're gonna hit various errors until the config is correct and complete — that's just the journey 😭. When the CMP server reports an error, the client will by default check the protection of the CMP response message. But some CMP services just... don't protect negative responses 🙈. In that case the client rejects them, so their contents never get shown — even though they usually contain hints that would've been so helpful for diagnostics. To help you out in these cases, the CMP client offers a workaround via the -unprotected_errors option, which lets you accept those negative messages. Slay.

And one last thing 🌈: if OpenSSL was built with trace support enabled (e.g. ./config enable-trace) and the environment variable OPENSSL_TRACE includes HTTP, then the requests and the response headers transferred via HTTP get printed. Free visibility, no cap.

💖 EXAMPLES 💖

🌸 Simple examples using the default OpenSSL configuration file

Okay so this CMP client ships with demonstrative CMP sections inside the example config file openssl/apps/openssl.cnf, and you can use those to vibe with the Insta Demo CA so easily 🎀

To enroll an initial certificate from that CA, literally just run these shell commands:

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

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

That should give you the file insta.cert.pem, which holds a shiny new certificate for the private key living in insta.priv.pem ✨ Wanna look at it? Peep it with, like:

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

If your network setup needs an HTTP proxy, you can pass it the usual way — via the environment variable http_proxy, or via the -proxy option in the configuration file, or via the CMP command-line argument -proxy, like 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 can be protected in signature-based manner — in that case the trust anchor is insta.ca.crt, and the client may use any certificate it already got from that CA, as specified in the [signature] section of the example configuration. You can combine that with the [insta] section simply by:

openssl cmp -section insta,signature

By default the CMP IR message type gets used, but CR works exactly the same here. You can specify it straight on the command line:

openssl cmp -section insta -cmd cr

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

openssl cmp -section insta,cr

Wanna update the enrolled certificate? Just call:

openssl cmp -section insta,kur,signature

…which uses signature-based protection with the certificate that's getting updated. Lowkey important: for certificate updates, MAC-based protection should generally not be used 🙈

Same energy for revoking — any previously enrolled certificate may be revoked by:

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

or

openssl cmp -section insta,rr,signature

There are so many more options you can give 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 — like "v3_req" in openssl/apps/openssl.cnf:

openssl cmp -section insta,cr -reqexts v3_req

🦋 Certificate enrollment

The following examples don't make use of a configuration file at first. They assume a CMP server can be contacted on the local TCP port 80 and that it 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 doesn't have the CA certificate yet, so we specify the name of the CA with the -recipient option and save any CA certificates we might receive into the "capubs.pem" file 💾

Heads up bestie: in the command line usage examples below, the "\" at line ends is just for formatting — each of the command invocations should actually 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 need updating, 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 — go off, keep refreshing that cert 🔁✨

🧚 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 — especially for certificate enrollment — you usually need to set a ton of parameters, and doing that on the command line is tedious and error-prone 😭 So the client offers the possibility to read options from sections of the OpenSSL config file, usually called openssl.cnf. And the values found there can still be extended, and even overridden, by any subsequently loaded sections and on the command line 🫶

After including these sections in the configuration file:

[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

👀 SEE ALSO 👀

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

📜 HISTORY 📜

The cmp application was added in OpenSSL 3.0 ✨

The -engine option was deprecated in OpenSSL 3.0 🫠

The -oldwithold, -newwithnew, -newwithold, -oldwithnew, The -srvcertout, and -serial option were added in OpenSSL 3.2, as well as an extension of -cacertsout to use when getting CA certificates. Since then, the -issuer may be used also for certificates to be revoked.

The -profile and -no_cache_extracerts options were added in OpenSSL 3.3, as well as support for delayed delivery of all types of response messages ⏳

The -template, -crlcert, -oldcrl, -crlout, -crlform and -rsp_crl options were added in OpenSSL 3.4.

-centralkeygen, b<-newkeyout>, -rsp_key and -rsp_keypass were added in OpenSSL 3.5 👑

Copyright 2007-2026 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>.

aaaand that's a wrap bestie 🎀 this whole glow-up was brought to you by OpenSSL 3.5.9, dated 2026-09-29 — go forth and cmp your heart out 💅✨

📦 where this page comes from