OPENSSL-X509(1ossl) OpenSSL OPENSSL-X509(1ossl) NAME openssl-x509 - Certificate display and signing command SYNOPSIS openssl x509 [-help] [-in filename|uri] [-passin arg] [-new] [-x509toreq] [-req] [-copy_extensions arg] [-inform DER|PEM] [-vfyopt nm:v] [-key file- name|uri] [-keyform DER|PEM|P12] [-signkey filename|uri] [-out filename] [-outform DER|PEM] [-nocert] [-noout] [-dateopt] [-text] [-certopt option] [-fingerprint] [-alias] [-serial] [-startdate] [-enddate] [-dates] [-sub- ject] [-issuer] [-nameopt option] [-email] [-hash] [-subject_hash] [-sub- ject_hash_old] [-issuer_hash] [-issuer_hash_old] [-ext extensions] [-oc- spid] [-ocsp_uri] [-purpose] [-pubkey] [-modulus] [-multi] [-checkend num] [-checkhost host] [-checkemail host] [-checkip ipaddr] [-set_serial n] [-next_serial] [-not_before date] [-not_after date] [-days arg] [-pre- serve_dates] [-set_issuer arg] [-set_subject arg] [-subj arg] [-force_pub- key filename] [-clrext] [-extfile filename] [-extensions section] [-sigopt nm:v] [-badsig] [-digest] [-CA filename|uri] [-CAform DER|PEM|P12] [-CAkey filename|uri] [-CAkeyform DER|PEM|P12] [-CAserial filename] [-CAcreateser- ial] [-trustout] [-setalias arg] [-clrtrust] [-addtrust arg] [-clrreject] [-addreject arg] [-rand files] [-writerand file] [-provider name] [-provider-path path] [-provparam [name:]key=value] [-propquery propq] DESCRIPTION This command is a multi-purposes certificate handling command. It can be used to print certificate information, convert certificates to various forms, edit certificate trust settings, generate certificates from scratch or from certification requests and then self-signing them or signing them like a "micro CA". Generated certificates bear X.509 version 3. Unless specified otherwise, key identifier extensions are included as described in x509v3_config(5). Since there are a large number of options they will split up into various sections. OPTIONS Input, Output, and General Purpose Options -help Print out a usage message. -in filename|uri This specifies the input to read a certificate from or the input file for reading a certificate request if the -req flag is used. In both cases this defaults to standard input. This option cannot be combined with the -new flag. -passin arg The key and certificate file password source. For more information about the format of arg see openssl-passphrase-options(1). -newGenerate a certificate from scratch, not using an input certificate or certificate request. So this excludes the -in and -req options. In- stead, the -set_subject option needs to be given. The public key to include can be given with the -force_pubkey option and defaults to the key given with the -key (or -signkey) option, which implies self-signa- ture. -x509toreq Output a PKCS#10 certificate request (rather than a certificate). The -key (or -signkey) option must be used to provide the private key for self-signing; the corresponding public key is placed in the subjectP- KInfo field. X.509 extensions included in a certificate input are not copied by de- fault. X.509 extensions to be added can be specified using the -extfile option. -reqBy default a certificate is expected on input. With this option a PKCS#10 certificate request is expected instead, which must be cor- rectly self-signed. X.509 extensions included in the request are not copied by default. X.509 extensions to be added can be specified using the -extfile op- tion. -copy_extensions arg Determines how to handle X.509 extensions when converting from a cer- tificate to a request using the -x509toreq option or converting from a request to a certificate using the -req option. If arg is none or this option is not present then extensions are ignored. If arg is copy or copyall then all extensions are copied, except that subject identifier and authority key identifier extensions are not taken over when produc- ing a certificate request. The -ext option can be used to further restrict which extensions to copy. -inform DER|PEM The input file format to use; by default PEM is tried first. See openssl-format-options(1) for details. -vfyopt nm:v Pass options to the signature algorithm during verify operations. Names and values of these options are algorithm-specific. -key filename|uri This option provides the private key for signing a new certificate or certificate request. Unless -force_pubkey is given, the corresponding public key is placed in the new certificate or certificate request, re- sulting in a self-signature. This option cannot be used in conjunction with the -CA option. It sets the issuer name to the subject name (i.e., makes it self-is- sued). Unless the -preserve_dates option is supplied, it sets the va- lidity start date to the current time and the end date to a value de- termined by the -days option. Start date and end date can also be ex- plicitly supplied with options -not_before and -not_after. -signkey filename|uri This option is an alias of -key. -keyform DER|PEM|P12 The key input format; unspecified by default. See openssl-format-op- tions(1) for details. -out filename This specifies the output filename to write to or standard output by default. -outform DER|PEM The output format; the default is PEM. See openssl-format-options(1) for details. -nocert Do not output a certificate (except for printing as requested by below options). -noout This option prevents output except for printing as requested by below options. Certificate Printing Options Note: the -alias and -purpose options are also printing options but are de- scribed in the "Trust Settings" section. -dateopt Specify the date output format. Values are: rfc_822 and iso_8601. De- faults to rfc_822. -text Prints out the certificate in text form. Full details are printed in- cluding the public key, signature algorithms, issuer and subject names, serial number any extensions present and any trust settings. -certopt option Customise the print format used with -text. The option argument can be a single option or multiple options separated by commas. The -certopt switch may be also be used more than once to set multiple options. See the "Text Printing Flags" section for more information. -fingerprint Calculates and prints the digest of the DER encoded version of the en- tire certificate (see digest options). This is commonly called a "fin- gerprint". Because of the nature of message digests, the fingerprint of a certificate is unique to that certificate and two certificates with the same fingerprint can be considered to be the same. -alias Prints the certificate "alias" (nickname), if any. -serial Prints the certificate serial number. -startdate Prints out the start date of the certificate, that is the notBefore date. -enddate Prints out the expiry date of the certificate, that is the notAfter date. -dates Prints out the start and expiry dates of a certificate. -subject Prints the subject name. -issuer Prints the issuer name. -nameopt option This specifies how the subject or issuer names are displayed. See openssl-namedisplay-options(1) for details. -email Prints the email address(es) if any. -hash Synonym for "-subject_hash" for backward compatibility reasons. -subject_hash Prints the "hash" of the certificate subject name. This is used in OpenSSL to form an index to allow certificates in a directory to be looked up by subject name. -subject_hash_old Prints the "hash" of the certificate subject name using the older algo- rithm as used by OpenSSL before version 1.0.0. -issuer_hash Prints the "hash" of the certificate issuer name. -issuer_hash_old Prints the "hash" of the certificate issuer name using the older algo- rithm as used by OpenSSL before version 1.0.0. -ext extensions Prints out the certificate extensions in text form. Can also be used to restrict which extensions to copy. Extensions are specified with a comma separated string, e.g., "subjectAltName, subjectKeyIdentifier". See the x509v3_config(5) manual page for the extension names. -ocspid Prints the OCSP hash values for the subject name and public key. -ocsp_uri Prints the OCSP responder address(es) if any. -purpose This option performs tests on the certificate extensions and outputs the results. For a more complete description see "Certificate Exten- sions" in openssl-verification-options(1). -pubkey Prints the certificate's SubjectPublicKeyInfo block in PEM format. -modulus This option prints out the value of the modulus of the public key con- tained in the certificate. -multi This option prints selected information about all certificates con- tained in the input. Certificate Checking Options -checkend arg Without -multi checks if the certificate expires within the next arg seconds and exits nonzero if it will expire or zero if not. With -multi checks if any certificate in the input will expire within the next arg seconds and exits nonzero if any will expire or zero if none will. -checkhost host Check that the certificate matches the specified host. -checkemail email Check that the certificate matches the specified email address. -checkip ipaddr Check that the certificate matches the specified IP address. Certificate Output Options -set_serial n Specifies the serial number to use. This option can be used with the -key, -signkey, or -CA options. If used in conjunction with the -CA option the serial number file (as specified by the -CAserial option) is not used. The serial number can be decimal or hex (if preceded by "0x"). -next_serial Set the serial to be one more than the number in the certificate. -not_before date This allows the start date to be explicitly set. The format of the date is YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure), or YYYYMMD- DHHMMSSZ (the same as an ASN1 GeneralizedTime structure). In both for- mats, seconds SS and timezone Z must be present. Alternatively, you can also use "today". Cannot be used together with the -preserve_dates option. -not_after date This allows the expiry date to be explicitly set. The format of the date is YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure), or YYYYMMDDHHMMSSZ (the same as an ASN1 GeneralizedTime structure). In both formats, seconds SS and timezone Z must be present. Alterna- tively, you can also use "today". Cannot be used together with the -preserve_dates option. This over- rides the option -days. -days arg Specifies the number of days from today until a newly generated cer- tificate expires. The default is 30. Cannot be used together with the option -preserve_dates. If option -not_after is set, the explicit expiry date takes precedence. -preserve_dates When signing a certificate, preserve "notBefore" and "notAfter" dates of any input certificate instead of adjusting them to current time and duration. Cannot be used together with the options -days, -not_before and -not_after. -set_issuer arg When a certificate is created set its issuer name to the given value. See -set_subject on how the arg must be formatted. -set_subject arg When a certificate is created set its subject name to the given value. When the certificate is self-signed the issuer name is set to the same value, unless the -set_issuer option is given. The arg must be formatted as "/type0=value0/type1=value1/type2=...". Special characters may be escaped by "\" (backslash), whitespace is re- tained. Empty values are permitted, but the corresponding type will not be included in the certificate. 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 AttributeValue- Assertions (AVAs) that specify the members of the set. Example: "/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe" This option can be used with the -new and -force_pubkey options to cre- ate a new certificate without providing an input certificate or cer- tificate request. -subj arg This option is an alias of -set_subject. -force_pubkey filename When a new certificate or certificate request is created set its public key to the given key instead of the key contained in the input or given with the -key (or -signkey) option. If the input contains no public key but a private key, its public part is used. This option can be used in conjunction with -new and -set_subject to directly generate a certificate containing any desired public key. This option is also useful for creating self-issued certificates that are not self-signed, for instance when the key cannot be used for sign- ing, such as DH. -clrext When transforming a certificate to a new certificate by default all certificate extensions are retained. When transforming a certificate or certificate request, the -clrext op- tion prevents taking over any extensions from the source. In any case, when producing a certificate request, neither subject identifier nor authority key identifier extensions are included. -extfile filename Configuration file containing certificate and request X.509 extensions to add. When both of the -extfile filename and -extensions section options are given, the extensions to add are taken from the named section of the file named filename. This file must exist, be readable, and all the listed extensions must be valid. If only the -extfile filename option is given, the section name to use is taken from the value of the variable named "extensions" in the file's unnamed section (also called its default section, see con- fig(5)). If no extensions setting is found, the file's default (un- named) section itself is instead used as the list of extensions to add. As before, the file must be readable and all the extensions must be valid. Prior to OpenSSL 4.0, the -extensions option required that the -extfile option be also specified. As of OpenSSL 4.0 the default configuration file is used instead as described below. If only the -extensions section option is given, the named section of the default configuration file, whether from the "OPENSSL_CONF" envi- ronment variable, or the built-in default, is used as list of exten- sions to add. As before, the file must be readable and all the exten- sions must be valid. If neither of the options are given, an attempt is made to open the de- fault configuration file (as detailed above). If the file does not ex- ist or cannot be opened, no extensions are added. If the unnamed sec- tion (default, see config(5)) of the file does not list an extensions variable, no extensions are added. Otherwise, the section named by the extensions variable is taken to be the list of extensions to add. The extensions listed there must all be valid. -extensions section The section in the extfile to add X.509 extensions from. See the de- scription of -extfile above for details. See the x509v3_config(5) manual page for details of the extension sec- tion format. -sigopt nm:v Pass options to the signature algorithm during sign operations. This option may be given multiple times. Names and values provided using this option are algorithm-specific. -badsig Corrupt the signature before writing it; this can be useful for test- ing. -digest The digest to use. This affects any signing or printing option that uses a message digest, such as the -fingerprint, -key, and -CA options. Any digest supported by the openssl-dgst(1) command can be used. If not specified then SHA1 is used with -fingerprint or the default digest for the signing algorithm is used, typically SHA256. Micro-CA Options -CA filename|uri Specifies the "CA" certificate to be used for signing. When present, this behaves like a "micro CA" as follows: The subject name of the "CA" certificate is placed as issuer name in the new certificate, which is then signed using the "CA" key given as detailed below. This option cannot be used in conjunction with -key (or -signkey). This option is normally combined with the -req option referencing a CSR. Without the -req option the input must be an existing certificate unless the -new option is given, which generates a certificate from scratch. -CAform DER|PEM|P12, The format for the CA certificate; unspecified by default. See openssl-format-options(1) for details. -CAkey filename|uri Sets the CA private key to sign a certificate with. The private key must match the public key of the certificate given with -CA. If this option is not provided then the key must be present in the -CA input. -CAkeyform DER|PEM|P12 The format for the CA key; unspecified by default. See openssl-for- mat-options(1) for details. -CAserial filename Sets the CA serial number file to use. When creating a certificate with this option and with the -CA option, the certificate serial number is stored in the given file. This file consists of one line containing an even number of hex digits with the serial number used last time. After reading this number, it is incre- mented and used, and the file is updated. The default filename consists of the CA certificate file base name with .srl appended. For example if the CA certificate file is called mycac- ert.pem it expects to find a serial number file called mycacert.srl. If the -CA option is specified and neither <-CAserial> or <-CAcreatese- rial> is given and the default serial number file does not exist, a random number is generated; this is the recommended practice. -CAcreateserial With this option and the -CA option the CA serial number file is cre- ated if it does not exist. A random number is generated, used for the certificate, and saved into the serial number file determined as de- scribed above. Trust Settings A trusted certificate is an ordinary certificate which has several addi- tional pieces of information attached to it such as the permitted and pro- hibited uses of the certificate and possibly an "alias" (nickname). Normally when a certificate is being verified at least one certificate must be "trusted". By default a trusted certificate must be stored locally and must be a root CA: any certificate chain ending in this CA is then usable for any purpose. Trust settings currently are only used with a root CA. They allow a finer control over the purposes the root CA can be used for. For example, a CA may be trusted for SSL client but not SSL server use. See openssl-verification-options(1) for more information on the meaning of trust settings. Future versions of OpenSSL will recognize trust settings on any certifi- cate: not just root CAs. -trustout Mark any certificate PEM output as <trusted> certificate rather than ordinary. An ordinary or trusted certificate can be input but by de- fault an ordinary certificate is output and any trust settings are dis- carded. With the -trustout option a trusted certificate is output. A trusted certificate is automatically output if any trust settings are modified. -setalias arg Sets the "alias" of the certificate. This will allow the certificate to be referred to using a nickname for example "Steve's Certificate". -clrtrust Clears all the permitted or trusted uses of the certificate. -addtrust arg Adds a trusted certificate use. Any object name can be used here but currently only clientAuth, serverAuth, emailProtection, and anyExtend- edKeyUsage are defined. As of OpenSSL 1.1.0, the last of these blocks all purposes when rejected or enables all purposes when trusted. Other OpenSSL applications may define additional uses. -clrreject Clears all the prohibited or rejected uses of the certificate. -addreject arg Adds a prohibited trust anchor purpose. It accepts the same values as the -addtrust option. Generic options -rand files, -writerand file See "Random State Options" in openssl(1) for details. -provider name -provider-path path -provparam [name:]key=value -propquery propq See "Provider Options" in openssl(1), provider(7), and property(7). Text Printing Flags As well as customising the name printing format, it is also possible to customise the actual fields printed using the certopt option when the text option is present. The default behaviour is to print all fields. compatible Use the old format. This is equivalent to specifying no printing op- tions at all. no_header Don't print header information: that is the lines saying "Certificate" and "Data". no_version Don't print out the version number. no_serial Don't print out the serial number. no_signame Don't print out the signature algorithm used. no_validity Don't print the validity, that is the notBefore and notAfter fields. no_subject Don't print out the subject name. no_issuer Don't print out the issuer name. no_pubkey Don't print out the public key. no_sigdump Don't give a hexadecimal dump of the certificate signature. no_aux Don't print out certificate trust information. no_extensions Don't print out any X509V3 extensions. ext_default Retain default extension behaviour: attempt to print out unsupported certificate extensions. ext_error Print an error message for unsupported certificate extensions. ext_parse ASN1 parse unsupported extensions. ext_dump Hex dump unsupported extensions. ca_default The value used by openssl-ca(1), equivalent to no_issuer, no_pubkey, no_header, and no_version. EXAMPLES Note: in these examples the '\' means the example should be all on one line. Print the contents of a certificate: openssl x509 -in cert.pem -noout -text Print the "Subject Alternative Name" extension of a certificate: openssl x509 -in cert.pem -noout -ext subjectAltName Print more extensions of a certificate: openssl x509 -in cert.pem -noout -ext subjectAltName,nsCertType Print the certificate serial number: openssl x509 -in cert.pem -noout -serial Print the certificate subject name: openssl x509 -in cert.pem -noout -subject Print the certificate subject name in RFC2253 form: openssl x509 -in cert.pem -noout -subject -nameopt RFC2253 Print the certificate subject name in oneline form on a terminal supporting UTF8: openssl x509 -in cert.pem -noout -subject -nameopt oneline,-esc_msb Print the certificate SHA1 fingerprint: openssl x509 -sha1 -in cert.pem -noout -fingerprint Convert a certificate from PEM to DER format: openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER Convert a certificate to a certificate request: openssl x509 -x509toreq -in cert.pem -out req.pem -key key.pem Convert a certificate request into a self-signed certificate using exten- sions for a CA: openssl x509 -req -in careq.pem -extfile openssl.cnf -extensions v3_ca \ -key key.pem -out cacert.pem Sign a certificate request using the CA certificate above and add user cer- tificate extensions: openssl x509 -req -in req.pem -extfile openssl.cnf -extensions v3_usr \ -CA cacert.pem -CAkey key.pem -CAcreateserial Set a certificate to be trusted for SSL client use and change set its alias to "Steve's Class 1 CA" openssl x509 -in cert.pem -addtrust clientAuth \ -setalias "Steve's Class 1 CA" -out trust.pem Check if any certificates in a chain are due to expire within the next 30 days (returns zero if none will expire, nonzero if any will expire): openssl x509 -in chain.pem -multi -checkend $[3600*24*30] \ && echo 'perform renewal' || echo 'renewal unnecessary' NOTES The conversion to UTF8 format used with the name options assumes that T61Strings use the ISO8859-1 character set. This is wrong but Netscape and MSIE do this as do many certificates. So although this is incorrect it is more likely to print the majority of certificates correctly. The -email option searches the subject name and the subject alternative name extension. Only unique email addresses will be printed out: it will not print the same address more than once. BUGS It is possible to produce invalid certificates or requests by specifying the wrong private key, using unsuitable X.509 extensions, or using incon- sistent options in some cases: these should be checked. There should be options to explicitly set such things as start and end dates rather than an offset from the current time. SEE ALSO openssl(1), openssl-req(1), openssl-ca(1), openssl-genrsa(1), openssl-gendsa(1), openssl-verify(1), config(5), x509v3_config(5) HISTORY The hash algorithm used in the -subject_hash and -issuer_hash options be- fore OpenSSL 1.0.0 was based on the deprecated MD5 algorithm and the encod- ing of the distinguished name. In OpenSSL 1.0.0 and later it is based on a canonical version of the DN using SHA1. This means that any directories us- ing the old form must have their links rebuilt using openssl-rehash(1) or similar. The -signkey option has been renamed to -key in OpenSSL 3.0, keeping the old name as an alias. The -C option was removed in OpenSSL 3.0. Since OpenSSL 3.2, generated certificates bear X.509 version 3, and key identifier extensions are included by default. The -engine option was removed in OpenSSL 4.0. OpenSSL 4.0 added support for specifying extensions to add via the default configuration file. See -extfile above for details. As of OpenSSL 4.0, the x509 utility no longer has specialised built-in logic to add the SKID or AKID extensions, they are handled through configu- ration files and command-line options just like any other extension. COPYRIGHT Copyright 2000-2026 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>. 4.0.2 2026-08-25 OPENSSL-X509(1ossl)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | NOTES | BUGS | SEE ALSO | HISTORY | COPYRIGHT
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=openssl-x509&sektion=1&manpath=FreeBSD+Ports+15.1.quarterly>