OPENSSL-CMP(1ossl)

📦
version 15.1 · 2 versions
, in freebsd 15.1

💅 openssl-cmp 💅

🎀 NAME 🎀

okay so openssl-cmp is the Certificate Management Protocol (CMP, RFCs 9810 and 9811) application. That’s the NAME vibe, bestie — CMP app, no cap. 💖

✨ SYNOPSIS ✨

here’s the whole shape of it, brace yourself — the brackets are exactly as printed, including the -centralkeygen line. 🫶

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 🌸

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. slay. ✨

👑 OPTIONS 👑

  • -help — Display a summary of all options. short and sweet.
  • -config filename — Configuration file to use. An empty string "" means none. Default filename is from the environment variable OPENSSL_CONF.
  • -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. layered, bestie.

  • -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.

🦋 Generic message options 🦋

  • -cmd ir|cr|kur|p10cr|rr|genm — CMP command to execute. Currently implemented commands are:
    • ir — Initialization Request
    • cr — Certificate Request
    • p10cr — PKCS#10 Certification Request (for legacy support)
    • kur — Key Update Request
    • rr — Revocation Request
    • genm — General Message

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. iconic.

  • -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.
  • -profile name — Name of a certificate profile to place in the PKIHeader generalInfo field of request messages.
  • -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'.
  • -template filename — The file to save any CRMF certTemplate in DER format received in a genp message with id-it-certReqTemplate.
  • -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. noted, bestie.

🎀 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. got it?
  • -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).
  • -centralkeygen — Request central key generation for certificate enrollment. This applies to -cmd ir|cr|kur|p10cr.
  • -newkeyout filename — File to save centrally generated private key, in PEM format.
  • -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" check the DN energy.
  • -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, 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.
  • -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 — the name of the section in your OpenSSL config file that defines the policies you want set as a certificate request extension. Heads up bestie: you literally cannot use this one together with -policy_oids. Pick a lane 💅
  • -policy_oids names — one or more OIDs, separated by commas and/or whitespace, to add as the certificate policies request extension. And yes, since whitespace counts as a separator, if you're using whitespace the whole argument has to be wrapped in "...". Same deal: this one cannot be used together with -policies. ✨
  • -policy_oids_critical — makes the policies you passed with -policy_oids critical. That's it. That's the whole job. 🔥
  • -popo number — the Proof-of-possession (POPO) method to use for IR/CR/KUR. The values are -1..<2>:
    • -1 = NONE, which implies central key generation
    • 0 = RAVERIFIED
    • 1 = SIGNATURE (this is the default, bestie 🫶)
    • 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 private key, no signature POPO, that's just how it is 😭
  • -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 you're using -popo -1 or -popo 0 — and the respective public key is placed in the certification request, rather than taking over the public key contained in the PKCS#10 CSR. Slight glow-up, slightly different rules, iykyk ✨

PKCS#10 CSR input can 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. So it's doing double duty, main character energy 💅

  • -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 (and again, whitespace means the whole argument must be wrapped 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. Just this one. Not the others. Noted 📝

  • -implicit_confirm — request implicit confirmation of newly enrolled certificates. Polite little shortcut 🎀
  • -disable_confirm — do not send the certificate confirmation message for a newly enrolled certificate without requesting implicit confirmation. This exists to cope with broken servers that don't support implicit confirmation correctly.
⚠️ WARNING: This leads to behavior violating RFC 9810. Like, actually violating it. Fr fr. Don't do this unless a broken server forces your hand 💀
  • -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. It's giving "just the middle of the sandwich" 🥪

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, iconic ⭐

🎀 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. Both -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 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. She's doing a LOT of behind-the-scenes work, absolute queen behavior 👑✨

  • -issuer name — the X.509 Distinguished Name (DN) to place as the issuer field in the requested certificate template in IR/CR/KUR/RR messages. If you give the NULL-DN ("/") then no issuer is placed in the template. Empty. Blank. Nothing. 🫥

If provided and neither -recipient nor -srvcert is given, the issuer DN is used as the 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. Don't freestyle the format, bestie 💅

  • -serial number — specify the serial number of the certificate to be revoked in the revocation request. The serial number can be decimal or hex (if preceded by "0x"). Pick your fighter 🔢
  • -revreason number — set the CRLReason to be included in the revocation request (RR). Values are 0..10 or -1 for none, and -1 (aka none) 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)
 }

Notice how value 7 is just... not used. Skipped. Gone. We don't talk about 7 🙈

🌈 Message transfer options 🌈

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

This option excludes -port and -use_mock_srv. It's 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. So the URL is basically the boss of several other options 🧚

  • -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 — and note that using TLS may be required by -tls_used or by -server with the prefix "https" — as well as any path, userinfo, 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. The env var fallback chain is giving "we asked literally everyone before deciding" 🫶

  • -no_proxy addresses — the list of IP addresses and/or DNS names of servers not to use an HTTP(S) proxy for, separated by commas and/or whitespace (and yes, whitespace again means the whole argument must be wrapped in "..."). The default is from the environment variable "no_proxy" if set, else "NO_PROXY". This option is ignored if -server is not given. 🚫
  • -recipient name — the 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:

  1. the subject of the CMP server certificate given with the -srvcert option
  2. the -issuer option
  3. the issuer of the certificate given with the -oldcert option
  4. the issuer of the CMP client certificate (-cert option)

...as far as any of those is present, else the NULL-DN as last resort. It's a whole fallback chain, a relay race, and the NULL-DN is the anchor leg 🏃‍♀️💨

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. Clingy in a healthy way 🫶
  • -msg_timeout seconds — the 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 — the maximum total number of seconds a transaction may take, including polling etc. A value <= 0 means no limitation (waiting indefinitely). Default is 0. So by default we wait forever, no cap 💀

💜 Server authentication options 💜

  • -trusted filenames|uris — the certificate(s), typically of root CAs, that 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. So: not one specific cert, but a whole valid family tree 🌳✨

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 (whitespace = wrap the whole argument in "...", you know the drill by now 🎀). 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. Different verification, different rules, bestie 💅

  • -untrusted filenames|uris — the non-trusted intermediate CA certificate(s) bestie, like the go-betweens of the cert world 🌈. Any extra certs you drop in with -cert get appended onto this list. All of these certs can be useful for cert path construction for your own CMP signer certificate (so they can go in the extraCerts field of request messages) and for the TLS client certificate (if TLS is being used), and also for chain building when validating server certificates (checking signature-based CMP message protection) and when validating newly enrolled certificates.

You can give multiple sources, separated by commas and/or whitespace — and if you're going the whitespace route, the whole argument has to be wrapped in "..." (yes, the whole thing, no cap 💅). Each source may contain multiple certificates.

  • -srvcert filename|uri — the specific CMP server certificate you expect and directly trust (even if it's expired, she's still iconic 👑) when verifying signature-based protection of CMP response messages. This pins the accepted server and means the -trusted option gets ignored entirely.

If you set it, the subject of the certificate is also used as the default value for the recipient of CMP requests and as the default value for the expected sender of CMP responses. Two-for-one slay ✨.

  • -expect_sender name — the Distinguished Name (DN) you expect in the sender field of incoming CMP messages. Defaults to the subject DN of the pinned -srvcert, if there is one.

This is the vibe check that makes sure only one particular entity is accepted as the CMP message signer, so attackers can't just grab arbitrary certificates from a trusted PKI hierarchy and fraudulently pose as a CMP server 😤. Ngl, this option gives you slightly more freedom than setting -srvcert, which pins the server to the holder of one particular certificate — whereas the expected sender name will keep matching even after the server cert gets updated. Growth 💖.

The argument must be formatted as /type0=value0/type1=value1/type2=.... For the deets, 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. Rules are rules... unless you pass this flag 🙈.
  • -unprotected_errors — accept missing or invalid protection of negative responses from the server. This applies to these 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

Like, it's giving "we're doing crimes for compatibility" 💀.

  • -no_cache_extracerts — don't cache certificates from the extraCerts field of CMP messages you received. By default they're kept around because they might be helpful for validating further messages. This option applies to both CMP clients and the mock server.

Either way, once an incoming message is successfully validated, its protection certificate (if there is one) gets cached for reuse when validating subsequent messages. That's done not only for efficiency but also so the sender doesn't have to keep stuffing its certificate and related chain into the extraCerts field of every later message in the same transaction. Efficiency queen 👑.

  • -srvcertout filename — the file where the successfully validated certificate (if any) gets saved — specifically the one the CMP server used for signature-based response message protection. If there's no such certificate, typically because the protection was MAC-based, that's indicated by deleting the file (if it existed). Ghosted 🫥.
  • -extracertsout filename — the file where you save the list of certificates contained in the extraCerts field of the last received response message that isn't a pollRep nor a PKIConf.
  • -cacertsout filename — the file where you 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 it's present and the optional oldWithNew certificate is received, that gets verified using the newWithNew certificate as the (only) trust anchor.
  • -newwithnew filename — you must provide this when -infotype rootCaCert is given, no exceptions bestie. 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) gets 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 that's 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. Chain of trust is only as strong as its weakest link, periodt 🧚.
  • -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, that's 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, that's indicated by deleting the file.
  • -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. Preferences matter 💅.
  • -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, that's 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). Backup plan energy 🫶.
  • -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 — she's the main character here 👑. 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 info 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 (they're a package deal, iykyk 💖).

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 the "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 get 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. Squad goals 🌸.

  • -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. Different lane, different rules 😌.

  • -key filename|uri — the corresponding private key file for the client's current certificate given in the -cert option. This is used for signature-based message protection unless the -secret option (indicating MAC-based protection) or -unprotected_requests is given.

It's 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's an encrypted PKCS#12 file. If it's not given here, the password will be prompted for if needed. No sneaky skips 💅.
  • -digest name — picks the digest name used in RFC 9810's MSG_SIG_ALG and also as the one-way function (OWF) in MSG_MAC_ALG, bestie. Wherever it applies, that's what covers message protection and proof-of-possession (POPO) signatures. Wanna see what you can pick from? openssl list -digest-commands has the whole lineup. Defaults to sha256 💅
  • -mac name — sets the name of the MAC algorithm in MSG_MAC_ALG. To peep the supported MAC algorithms, run openssl list -mac-algorithms — and yes, you can combine a name with a supported digest algorithm, like hmacWithSHA256, iykyk. Defaults to hmac-sha1, kept for backward compatibility with RFC 4210.
  • -extracerts filenames|uris — certs to append in the extraCerts field whenever messages go out. They can also serve as the default CMP signer certificate chain to include 🎀

Multiple sources are allowed, separated by commas and/or whitespace (and in the whitespace case the whole argument has to be wrapped in "..."). Each source may contain multiple certificates, no cap.

  • -unprotected_requests — sends request messages with no CMP-level protection at all. Living dangerously, love that for you 🙈

✨ Credentials format options ✨

  • -certform PEM|DER — the file format used when saving a certificate to a file. Default value is PEM.
  • -crlform PEM|DER — the file format used when saving a CRL to a file. Default value is DER. And ngl, DER is the preferred one because it enables more efficient storage of large CRLs 🌸
  • -keyform PEM|DER|P12|ENGINE — the format of the key input; unspecified by default. The details live in Format Options in openssl(1), go check it.
  • -otherpass arg — pass phrase source for the 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 you don't hand it over here, the password will be prompted for if needed — so no silent failure, just a lil pop-up moment.

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

  • -engine id — see Engine Options in openssl(1). Heads up though: 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 that specify keys: -key, -newkey, and -tls_key.

🌈 Provider options 🌈

  • -provider name
  • -provider-path path
  • -provparam [name:]key=value
  • -propquery propq

See Provider Options in openssl(1), provider(7), and property(7) — the holy trinity of provider lore, fr fr.

🎀 Random state options 🎀

  • -rand files, -writerand file — see Random State Options in openssl(1) for all the deets.

🦋 TLS connection options 🦋

  • -tls_used — makes the CMP client use TLS (regardless of whether other TLS-related options are set) for message exchange with the server via HTTP. This one is not supported with the -port option. It's implied if the -server option is given with the scheme https. And it gets ignored if the -server option isn't given, or if -use_mock_srv is given, or if -rspin is given with enough filename arguments. So many conditions, but she's worth it ✨

The following TLS-related options are ignored if TLS isn't used — keep that in mind before you @ me.

  • -tls_cert filename|uri — the client's TLS certificate, used for authenticating to the TLS server. If the source includes further certs, they get 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. The main character of the handshake 🔑
  • -tls_keypass arg — pass phrase source for the client's private TLS key -tls_key. It's also used for -tls_cert in case that one is an encrypted PKCS#12 file. If you don't provide it 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 the handshake 🫶
  • -tls_trusted filenames|uris — trusted certificate(s) used for validating the TLS server certificate. This implies hostname validation, periodt.

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.

Just so we're clear: the certificate verification options -verify_hostname, -verify_ip, and -verify_email have no effect on the certificate verification enabled via this option. Different verification, different vibe 💅

  • -tls_host name — the address to be checked during hostname validation. 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, like when a password is needed. Super useful for batch processing and testing. No interruptions, just vibes 😌
  • -repeat number — invoke the command the given positive number of times with the same parameters. Default is one invocation. Run it back, run it back 🔥
  • -reqin filenames — take the sequence of CMP requests to send to the server from the given file(s) instead of 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.

It gets ignored if the -rspin option is given, because in that case no requests are actually sent at all.

Note that in any case the client produces internally its sequence of CMP request messages. So like, all the options required for doing that (such as -cmd and all options providing the required parameters) need to be given also when the -reqin option is present. Can't skip the homework, bestie.

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's 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 isn't actually needed (because the internally produced certificate request message won't be sent), and its generation can be disabled using the options -popo -1 or -popo 0. Little lifesaver 🩹

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 — uses 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. Been there, annoyed the server, fixed it ✨
  • -reqout filenames — saves 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. Only so much room in the group chat 🎀

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

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

  • -rspin filenames — processes the sequence of CMP responses provided in the given file(s), without 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 only contacted if more responses are needed to complete the transaction. In that case the transaction will fail unless the server has been prepared to continue the already started transaction. Plot twist 😭

  • -rspout filenames — saves 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 — tests the client using the internal CMP server mock-up at API level, bypassing socket-based transfer via HTTP entirely. This excludes the -server and -port options. Fake it till you make it 🧪

👑 Mock server options 👑

  • -port number — acts as an 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. Also, the -rspin, -rspout, -reqin, and -reqout options so far are not supported in this mode. Current limitations, bestie, not a skill issue 💀
  • -max_msgs number — the maximum number of CMP (request) messages the CMP HTTP server mock-up should handle, which must be nonnegative. Default value is 0, which means 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. Polite but firm 💅
  • -srv_ref value — reference value to use as senderKID of the server in case no -srv_cert is given.
  • -srv_secret arg — password source for server authentication with a pre-shared key (secret). Shhh, it's a secret 🤫
  • -srv_cert filename|uri — the server's certificate. 💖
  • -srv_key filename|uri — the private key the server uses to sign messages.
  • -srv_keypass arg — where to get the pass phrase for the server's private key (and cert) file.
  • -srv_trusted filenames|uris — the trusted certs used to authenticate the client.
heads up bestie: the verification options -verify_hostname, -verify_ip, and -verify_email have no effect on the certificate verification turned on by this option. none. zero. nada. 🫶
  • -srv_untrusted filenames|uris — intermediate CA certs that might come in handy when validating client certificates.
  • -ref_cert filename|uri — the certificate to expect in RR messages and in any oldCertID inside KUR messages.
  • -rsp_cert filename|uri — the certificate to hand back as the mock enrollment result. ✨
  • -rsp_key filename|uri — the private key to hand back as the central key generation result.
  • -rsp_keypass arg — pass phrase source for rsp_cert and rsp_key.
  • -rsp_crl filename|uri — the CRL to return in a genp of type "crls".
  • -rsp_extracerts filenames|uris — extra certificates to shove into mock certification responses.
  • -rsp_capubs filenames|uris — CA certificates to include in the mock Initialization Response (IP) message.
  • -rsp_newwithnew filename|uri — the certificate returned in the newWithNew field of a genp of type rootCaKeyUpdate.
  • -rsp_newwithold filename|uri — the certificate returned in the newWithOld field of a genp of type rootCaKeyUpdate.
  • -rsp_oldwithnew filename|uri — the certificate returned in the oldWithNew field of a genp of type rootCaKeyUpdate.
  • -poll_count number — how many times the client has to poll before it actually gets a certificate. the suspense. 😭
  • -check_after number — the checkAfter value to include in the poll response (that's the number of seconds to wait, bestie).
  • -grant_implicitconf — grants implicit confirmation of the newly enrolled certificate. 💅
  • -pkistatus number — the PKIStatus to put 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 — a number representing the failure bits to include in the server response. valid range is 0 .. 2^27 - 1. yes that's a big number, no I'm not counting them for you.
  • -statusstring arg — the text to drop in as the status string in the server response.
  • -send_error — forces the server to reply with an error message. rude but okay. 💀
  • -send_unprotected — sends response messages without CMP-level protection.
  • -send_unprot_err — for 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, actually breaks the spec. consider yourself warned, bestie.
  • -accept_unprotected — accepts missing or invalid protection of requests.
  • -accept_unprot_err — accepts unprotected error messages from the client. so far this has no effect, because the server doesn't accept any error messages anyway. it's giving decorative. 🎀
  • -accept_raverified — accepts 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 the various options for certificate chain verification. the whole rundown lives in "Verification Options" in openssl-verification-options(1), so go read that for the details. ✨
okay so this part matters: 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 scope. 🫶

💬 NOTES 💬

So picture this: when a client obtains CA certificates from a CMP server — certs it's actually going to trust — like via the "caPubs" field of a certificate response, or using general messages with infoType "caCerts" or "rootCaCert", then authenticating that CMP server is particularly critical. like, main character level of important. 👑

So bestie, be extra careful setting up server authentication: use -trusted and the related options if you're doing certificate-based authentication, or -secret for MAC-based protection. And if the auth is certificate-based, you should use the -srvcertout option to grab the validated server certificate and then do an authorization check based on it. no cap, this is the part people skip and then regret. 🙈

When you're setting up CMP configurations and just, like, experimenting with enrollment options, you're gonna hit a bunch of errors until the config is correct and complete. that's normal, we've all been there. 😭

Here's the thing though: when the CMP server reports an error, the client will by default check the protection of the CMP response message. but some CMP services simply 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 be super helpful for diagnostics. 💀

For those situations the CMP client offers a workaround via the -unprotected_errors option, which lets you accept those negative messages. lifesaver fr fr. 🫶

And one more lil 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 out. handy for snooping on what's actually going over the wire. ⭐

🌸 EXAMPLES 🌸

💖 Simple examples using the default OpenSSL configuration file

Okay bestie, this CMP client ships with demonstrative CMP sections right inside the example configuration file openssl/apps/openssl.cnf, and you can use them to vibe with the Insta Demo CA super conveniently. Iconic.

So to enroll an initial certificate from that CA, literally all you need is these shell commands:

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

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

That should produce the file insta.cert.pem containing a new certificate for the private key held in insta.priv.pem. Want to look at it? Slay, just run:

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 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. Cute mutual auth moment 💅

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. You can use this 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. You can specify that 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

And to update the enrolled certificate, you may call:

openssl cmp -section insta,kur,signature

using signature-based protection with the certificate that is to be updated. > Heads up bestie: for certificate updates, MAC-based protection should generally not be used. Not me warning you, it's the manpage fr fr.

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/. Setting the scene ✨

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.

Quick note, iykyk: in the command line usage examples below, 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. Glow-up complete 💅

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. Periodt.

🌈 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. Not the vibe. So 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. So flexible 👑

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

✨ SEE ALSO ✨

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

Go read those too bestie, they're the supporting cast and they ate 🫶

👑 HISTORY 👑

The cmp application was added in OpenSSL 3.0.

The -engine option was deprecated in OpenSSL 3.0. (RIP, she's retired 💀)

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>.

🌸 okay that's the whole page bestie, you made it to the end!! this lil beauty is from OpenSSL version 3.5.6, dated 2026-04-07, and the manpage is OPENSSL-CMP(1ossl). go forth and enroll some certs, you're gonna slay 💖🦋✨

📦 where this page comes from