NAME
openssl - OpenSSL command line program
SYNOPSIS
openssl command [ options ... ] [ parameters ... ]
openssl list -standard-commands | -digest-commands | -cipher-commands | -cipher-algorithms | -digest-algorithms | -mac-algorithms | -public-key-algorithms
openssl no-XXX [ options ]
DESCRIPTION
OpenSSL is a cryptography toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) network protocols and related cryptography standards required by them.
The openssl program is a command line program for using the various cryptography functions of OpenSSL's crypto library from the shell. It can be used for
o Creation and management of private keys, public keys and parameters
o Public key cryptographic operations
o Creation of X.509 certificates, CSRs and CRLs
o Calculation of Message Digests and Message Authentication Codes
o Encryption and Decryption with Ciphers
o SSL/TLS Client and Server Tests
o Handling of S/MIME signed or encrypted mail
o Timestamp requests, generation and verificationCOMMAND SUMMARY
The openssl program provides a rich variety of commands (command in the "SYNOPSIS" above). Each command can have many options and argument parameters, shown above as options and parameters.
Detailed documentation and use cases for most standard subcommands are available (e.g., openssl-version(1) command. The environment variable OPENSSL_CONF can be used to specify a different location of the file. See Standard Commands
Parse an ASN.1 sequence. Certificate Authority (CA) Management. Cipher Suite Description Determination. CMS (Cryptographic Message Syntax) command. Certificate Revocation List (CRL) Management. CRL to PKCS#7 Conversion. Message Digest calculation. MAC calculations are superseded by dhparam
Generation and Management of Diffie-Hellman Parameters. Superseded by openssl-pkeyparam(1). DSA Data Management. DSA Parameter Generation and Management. Superseded by openssl-pkeyparam(1). EC (Elliptic curve) key processing. EC parameter manipulation and generation. Encryption, decryption, and encoding. Engine (loadable module) information and manipulation. Error Number to Error String Conversion. FIPS configuration installation. Generation of DSA Private Key from Parameters. Superseded by openssl-pkey(1). Generation of Private Key or Parameters. BLAKE2b-512 Digest BLAKE2s-256 Digest MD2 Digest MD4 Digest MD5 Digest MDC2 Digest RMD-160 Digest SHA-1 Digest SHA-2 224 Digest SHA-2 256 Digest SHA-2 384 Digest SHA-2 512 Digest SHA-3 224 Digest SHA-3 256 Digest SHA-3 384 Digest SHA-3 512 Digest SHA-3 SHAKE128 Digest SHA-3 SHAKE256 Digest SM3 Digest The following aliases provide convenient access to the most used encodings and ciphers. Depending on how OpenSSL was configured and built, not all ciphers listed here may be present. See aes128, aes-128-cbc, aes-128-cfb, aes-128-ctr, aes-128-ecb, aes-128-ofb
AES-128 Cipher AES-192 Cipher AES-256 Cipher Aria-128 Cipher Aria-192 Cipher Aria-256 Cipher Base64 Encoding Blowfish Cipher Camellia-128 Cipher Camellia-192 Cipher Camellia-256 Cipher CAST Cipher CAST5 Cipher Chacha20 Cipher DES Cipher Triple-DES Cipher IDEA Cipher RC2 Cipher RC4 Cipher RC5 Cipher SEED Cipher SM4 Cipher Details of which options are available depend on the specific command. This section describes some common options with common behavior. Provides a terse summary of all options. If an option takes an argument, the "type" of argument is also given. This terminates the list of options. It is mostly useful if any filename parameters start with a minus sign: Several OpenSSL commands can take input or generate output in a variety of formats. The list of acceptable formats, and the default, is described in each command documentation. The list of formats is described below. Both uppercase and lowercase are accepted. A binary format, encoded or parsed according to Distinguished Encoding Rules (DER) of the ASN.1 data language. Used to specify that the cryptographic material is in an OpenSSL engine. An engine must be configured or specified using the -engine option. In addition, the -input flag can be used to name a specific object in the engine. A password, such as the -passin flag often must be specified as well. A DER-encoded file containing a PKCS#12 object. It might be necessary to provide a decryption password to retrieve the private key. A text format defined in IETF RFC 1421 and IETF RFC 7468. Briefly, this is a block of base-64 encoding (defined in IETF RFC 4648), with specific lines used to mark the start and end: The object-type must match the type of object that is expected. For example a The following legacy object-type's are also supported for compatibility with earlier releases: An S/MIME object as described in IETF RFC 8551. Earlier versions were known as CMS and are compatible. Note that the parsing is simple and might fail to parse some legal data. The options to specify the format are as follows. Refer to the individual manpage to see which options are accepted. The format of the input or output streams. Format of a private key input source. Format of a CRL input source. Several commands accept password arguments, typically using -passin and -passout for input and output passwords respectively. These allow the password to be obtained from a variety of sources. Both of these options take a single argument whose format is described below. If no password argument is given and a password is required then the user is prompted to enter one: this will typically be read from the current terminal with echoing turned off. Note that character encoding may be relevant, please see pass:password
The actual password is password. Since the password is visible to utilities (like 'ps' under Unix) this form should only be used where security is not important. Obtain the password from the environment variable var. Since the environment of other processes is visible on certain platforms (e.g. ps under certain Unix OSes) this option should be used with caution. The first line of pathname is the password. If the same pathname argument is supplied to -passin and -passout arguments then the first line will be used for the input password and the next line for the output password. pathname need not refer to a regular file: it could for example refer to a device or named pipe. Read the password from the file descriptor number. This can be used to send the data via a pipe for example. Read the password from standard input. Part of validating a certificate includes verifying that the chain of CA's can be traced up to an existing trusted root. The following options specify how to list the trusted roots, also known as trust anchors. A collection of trusted roots is called a trust store. Note that OpenSSL does not provide a default set of trust anchors. Many Linux distributions include a system default and configure OpenSSL to point to that. Mozilla maintains an influential trust store that can be found at https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/. Load the specified file which contains one or more PEM-format certificates of CA's that are trusted. Do not load the default file of trusted certificates. Use the specified directory as a list of trust certificates. That is, files should be named with the hash of the X.509 SubjectName of each certificate. This is so that the library can extract the IssuerName, hash it, and directly lookup the file to get the issuer certificate. See -no-CApath
Do not use the default directory of trusted certificates. Use uri as a store of trusted CA certificates. The URI may indicate a single certificate, as well as a collection of them. With URIs in the Do not use the default store. Prior to OpenSSL 1.1.1, it was common for applications to store information about the state of the random-number generator in a file that was loaded at startup and rewritten upon exit. On modern operating systems, this is generally no longer necessary as OpenSSL will seed itself from a trusted entropy source provided by the operating system. These flags are still supported for special platforms or circumstances that might require them. It is generally an error to use the same seed file more than once and every use of -rand should be paired with -writerand. A file or files containing random data used to seed the random number generator. Multiple files can be specified separated by an OS-dependent character. The separator is Writes the seed data to the specified file upon exit. This file can be used in a subsequent command invocation. With the move to provider based cryptographic operations in OpenSSL 3.0, options were added to allow specific providers or sets of providers to be used. Use the provider identified by name and use all the methods it implements (algorithms, key storage, etc.). This option can be specified multiple time to load more than one provider. Specify the search path that is used to locate provider modules. The format of path varies depending on the operating system being used. Sometimes there may be more than one certificate chain leading to an end-entity certificate. This usually happens when a root or intermediate CA signs a certificate for another a CA in other organization. Another reason is when a CA might have intermediates that use two different signature formats, such as a SHA-1 and a SHA-256 digest. The following options can be used to provide data that will allow the OpenSSL command to generate an alternative chain. Specify whether the application should build the certificate chain to be provided to the server for the extra certificates via the -xkey, -xcert, and -xchain options. Specify an extra certificate, private key and certificate chain. These behave in the same manner as the -cert, -key and -cert_chain options. When specified, the callback returning the first valid chain will be in use by the client. The input format for the extra certificate and key, respectively. See -xchain_build
Specify whether the application should build the certificate chain to be provided to the server for the extra certificates via the -xkey, -xcert, and -xchain options. The input format for the extra certificate and key, respectively. See Verification Options
Many OpenSSL commands verify certificates. The details of how each command handles errors are documented on the specific command page. Verification is a complicated process, consisting of a number of separate steps that are detailed in the following paragraphs. First, a certificate chain is built up starting from the supplied certificate and ending in a root CA. It is an error if the whole chain cannot be built up. The chain is built up by looking up the certificate that signed (or issued) the certificate. It then repeats the process, until it gets to a certificate that is self-issued. The process of looking up the issuer's certificate itself involves a number of steps. After all certificates whose subject name matches the issuer name of the current certificate are subject to further tests. The relevant authority key identifier components of the current certificate (if present) must match the subject key identifier (if present) and issuer and serial number of the candidate issuer, in addition the keyUsage extension of the candidate issuer (if present) must permit certificate signing. The lookup first looks in the list of untrusted certificates and if no match is found the remaining lookups are from the trusted certificates. The root CA is always looked up in the trusted certificate list: if the certificate to verify is a root certificate then an exact match must be found in the trusted list. The second step is to check every untrusted certificate's extensions for consistency with the supplied purpose. If the -purpose option is not included then no checks are done. The supplied or "leaf" certificate must have extensions compatible with the supplied purpose and all other certificates must also be valid CA certificates. The precise extensions required are described in more detail in -verbose
Print extra information about the operations being performed. Perform validation checks using time specified by timestamp and not current system time. timestamp is the number of seconds since January 1, 1970 (i.e., the Unix Epoch). This option suppresses checking the validity period of certificates and CRLs against the current time. If option -attime is used to specify a verification time, the check is not suppressed. This disables non-compliant workarounds for broken certificates. Normally if an unhandled critical extension is present which is not supported by OpenSSL the certificate is rejected (as required by RFC5280). If this option is set critical extensions are ignored. Ignored. Checks end entity certificate validity by attempting to look up a valid CRL. If a valid CRL cannot be found an error occurs. Checks the validity of all certificates in the chain by attempting to look up valid CRLs. Enable support for delta CRLs. Enable extended CRL features such as indirect CRLs and alternate CRL signing keys. Enable the Suite B mode operation at 128 bit Level of Security, 128 bit or 192 bit, or only 192 bit Level of Security respectively. See RFC6460 for details. In particular the supported signature algorithms are reduced to support only ECDSA and SHA256 or SHA384 and only the elliptic curves P-256 and P-384. Set the certificate chain authentication security level to level. The authentication security level determines the acceptable signature and public key strength when verifying certificate chains. For a certificate chain to validate, the public keys of all the certificates must meet the specified security level. The signature algorithm security level is enforced for all the certificates in the chain except for the chain's trust anchor, which is either directly trusted or validated by means other than its signature. See -partial_chain
Allow verification to succeed even if a complete chain cannot be built to a self-signed trust-anchor, provided it is possible to construct a chain to a trusted certificate that might not be self-signed. Verify the signature on the self-signed root CA. This is disabled by default because it doesn't add any security. Allow the verification of proxy certificates. As of OpenSSL 1.1.0 this option is on by default and cannot be disabled. As of OpenSSL 1.1.0, since -trusted_first always on, this option has no effect. Parse file as a set of one or more certificates in PEM format. All certificates must be self-signed, unless the -partial_chain option is specified. This option implies the -no-CAfile, -no-CApath, and -no-CAstore options and it cannot be used with the -CAfile, -CApath or -CAstore options, so only certificates in the file are trust anchors. This option may be used multiple times. Parse file as a set of one or more certificates in PEM format. All certificates are untrusted certificates that may be used to construct a certificate chain from the subject certificate to a trust anchor. This option may be used multiple times. Enable policy processing and add arg to the user-initial-policy-set (see RFC5280). The policy arg can be an object name an OID in numeric form. This argument can appear more than once. Set policy variable require-explicit-policy (see RFC5280). Enables certificate policy processing. Print out diagnostics related to policy processing. Set policy variable inhibit-any-policy (see RFC5280). Set policy variable inhibit-policy-mapping (see RFC5280). The intended use for the certificate. If this option is not specified, this command will not consider certificate purpose during chain verification. Currently accepted uses are sslclient, sslserver, nssslserver, smimesign, smimeencrypt. Limit the certificate chain to num intermediate CA certificates. A maximal depth chain can have up to num+2 certificates, since neither the end-entity certificate nor the trust-anchor certificate count against the -verify_depth limit. Verify if email matches the email address in Subject Alternative Name or the email in the subject Distinguished Name. Verify if hostname matches DNS name in Subject Alternative Name or Common Name in the subject certificate. Verify if ip matches the IP address in Subject Alternative Name of the subject certificate. Use default verification policies like trust model and required certificate policies identified by name. The trust model determines which auxiliary trust or reject OIDs are applicable to verifying the given certificate chain. See the -addtrust and -addreject options for Name Format Options
OpenSSL provides fine-grain control over how the subject and issuer DN's are displayed. This is specified by using the -nameopt option, which takes a comma-separated list of options from the following set. An option may be preceded by a minus sign, Display the name using an old format from previous OpenSSL versions. Display the name using the format defined in RFC 2253. It is equivalent to esc_2253, esc_ctrl, esc_msb, utf8, dump_nostr, dump_unknown, dump_der, sep_comma_plus, dn_rev and sname. Display the name in one line, using a format that is more readable RFC 2253. It is equivalent to esc_2253, esc_ctrl, esc_msb, utf8, dump_nostr, dump_der, use_quote, sep_comma_plus_space, space_eq and sname options. Display the name using multiple lines. It is equivalent to esc_ctrl, esc_msb, sep_multiline, space_eq, lname and align. Escape the "special" characters in a field, as required by RFC 2253. That is, any of the characters Escape the "special" characters in a field as required by RFC 2254 in a field. That is, the NUL character and and of Escape non-printable ASCII characters, codes less than 0x20 (space) or greater than 0x7F (DELETE). They are displayed using RFC 2253 Escape any characters with the most significant bit set, that is with values larger than 127, as described in esc_ctrl. Escapes some characters by surrounding the entire string with quotation marks, Convert all strings to UTF-8 format first as required by RFC 2253. If the output device is UTF-8 compatible, then using this option (and not setting esc_msb) may give the correct display of multibyte characters. If this option is not set, then multibyte characters larger than 0xFF will be output as This option does not attempt to interpret multibyte characters in any way. That is, the content octets are merely dumped as though one octet represents each character. This is useful for diagnostic purposes but will result in rather odd looking output. Display the type of the ASN1 character string before the value, such as Any fields that would be output in hex format are displayed using the DER encoding of the field. If not set, just the content octets are displayed. Either way, the #XXXX... format of RFC 2253 is used. Dump non-character strings, such as ASN.1 OCTET STRING. If this option is not set, then non character string types will be displayed as though each content octet represents a single character. Dump all fields. When this used with dump_der, this allows the DER encoding of the structure to be unambiguously determined. Dump any field whose OID is not recognised by OpenSSL. Specify the field separators. The first word is used between the Relative Distinguished Names (RDNs) and the second is between multiple Attribute Value Assertions (AVAs). Multiple AVAs are very rare and their use is discouraged. The options ending in "space" additionally place a space after the separator to make it more readable. The sep_multiline starts each field on its own line, and uses "plus space" for the AVA separator. It also indents the fields by four characters. The default value is sep_comma_plus_space. Reverse the fields of the DN as required by RFC 2253. This also reverses the order of multiple AVAs in a field, but this is permissible as there is no ordering on values. Specify how the field name is displayed. nofname does not display the field at all. sname uses the "short name" form (CN for commonName for example). lname uses the long form. oid represents the OID in numerical form and is useful for diagnostic purpose. Align field values for a more readable output. Only usable with sep_multiline. Places spaces round the equal sign, Several commands use SSL, TLS, or DTLS. By default, the commands use TLS and clients will offer the lowest and highest protocol version they support, and servers will pick the highest version that the client offers that is also supported by the server. The options below can be used to limit which protocol versions are used, and whether TCP (SSL and TLS) or UDP (DTLS) is used. Note that not all protocols and flags may be available, depending on how OpenSSL was built. These options require or disable the use of the specified SSL or TLS protocols. When a specific TLS version is required, only that version will be offered or accepted. Only one specific protocol can be given and it cannot be combined with any of the no_ options. These options specify to use DTLS instead of DLTS. With -dtls, clients will negotiate any supported DTLS protocol version. Use the -dtls1 or -dtls1_2 options to support only DTLS1.0 or DTLS1.2, respectively. Use the engine identified by id and use all the methods it implements (algorithms, key storage, etc.), unless specified otherwise in the command-specific documentation or it is configured to do so, as described in ENVIRONMENT
The OpenSSL library can be take some configuration parameters from the environment. Some of these variables are listed below. For information about specific commands, see openssl-provider(1), tsget(1). For information about the use of environment variables in configuration, see OPENSSL_ia32cap(3), and openssl-env(7). Enable tracing output of OpenSSL library, by name. This output will only make sense if you know OpenSSL internals well. Also, it might not give you any output at all, depending on how OpenSSL was built. The value is a comma separated list of names, with the following available: The tracing functionality. General SSL/TLS. SSL/TLS cipher. ENGINE configuration. The function that is used by RSA, DSA (etc) code to select registered ENGINEs, cache defaults and functional references (etc), will generate debugging summaries. Reference counts in the ENGINE structure will be monitored with a line of generated for each change. PKCS#5 v2 keygen. PKCS#12 key generation. PKCS#12 decryption. Generates the complete policy tree at various point during X.509 v3 policy evaluation. BIGNUM context. openssl-ca(1), openssl-cms(1), openssl-crl2pkcs7(1), openssl-dhparam(1), openssl-dsaparam(1), openssl-ecparam(1), openssl-engine(1), openssl-gendsa(1), openssl-genrsa(1), openssl-mac(1), openssl-ocsp(1), openssl-pkcs12(1), openssl-pkcs8(1), openssl-pkeyparam(1), openssl-prime(1), openssl-rehash(1), openssl-rsa(1), openssl-s_client(1), openssl-s_time(1), openssl-smime(1), openssl-spkac(1), openssl-storeutl(1), openssl-verify(1), openssl-x509(1), crypto(7), ssl(7), HISTORY
The list -XXX-algorithms options were added in OpenSSL 1.0.0; For notes on the availability of other commands, see their individual manual pages. The -issuer_checks option is deprecated as of OpenSSL 1.1.0 and is silently ignored. Copyright 2000-2020 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.
Message Digest Commands
Encryption, Decryption, and Encoding Commands
OPTIONS
Common Options
openssl verify [flags...] -- -cert1.pem...Format Options
Text before the BEGIN line is ignored.
----- BEGIN object-type -----
OT43gQKBgQC/2OHZoko6iRlNOAQ/tMVFNq7fL81GivoQ9F1U0Qr+DH3ZfaH8eIkX
xT0ToMPJUzWAn8pZv0snA0um6SIgvkCuxO84OkANCVbttzXImIsL7pFzfcwV/ERK
UM6j0ZuSMFOCr/lGPAoOQU0fskidGEHi1/kW+suSr28TqsyYZpwBDQ==
----- END object-type -----
Text after the END line is also ignoredBEGIN X509 CERTIFICATE will not match if the command is trying to read a private key. The types supported include: ANY PRIVATE KEY
CERTIFICATE
CERTIFICATE REQUEST
CMS
DH PARAMETERS
DSA PARAMETERS
DSA PUBLIC KEY
EC PARAMETERS
EC PRIVATE KEY
ECDSA PUBLIC KEY
ENCRYPTED PRIVATE KEY
PARAMETERS
PKCS #7 SIGNED DATA
PKCS7
PRIVATE KEY
PUBLIC KEY
RSA PRIVATE KEY
SSL SESSION PARAMETERS
TRUSTED CERTIFICATE
X509 CRL
X9.42 DH PARAMETERS DSA PRIVATE KEY
NEW CERTIFICATE REQUEST
RSA PUBLIC KEY
X509 CERTIFICATE
Pass Phrase Options
Trusted Certificate Options
file: scheme, this acts as -CAfile or -CApath, depending on if the URI indicates a single file or directory. See openssl-s_server(1)) or client certificate chain (for example with -no-CAstore
Random State Options
;
for MS-Windows, , for OpenVMS, and : for all others. Another way to specify multiple files is to repeat this flag with different filenames.Provider Options
Extended Verification Options
-, to turn it off. The default value is oneline. The first four are the most commonly used.
,+"<>;, #
at the beginning of a string and leading or trailing spaces.()*.\XX notation where XX are the two hex digits representing the character value.". Without this option, individual special characters are preceded with a backslash character, \.\UXXXX for 16 bits or \WXXXXXXXX for 32 bits. In addition, any UTF8Strings will be converted to their character form first.BMPSTRING: Hello World.=, character which follows the field name.TLS Version Options
Engine Options
SEE ALSO
COPYRIGHT