OpenSSL

Cryptography and SSL/TLS Toolkit

openssl

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 verification

COMMAND 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-x509(1)).

Many commands use an external configuration file for some or all of their arguments and have a -config option to specify that file. The default name of the file is openssl.cnf in the default certificate storage area, which can be determined from the openssl-version(1) command. The environment variable OPENSSL_CONF can be used to specify a different location of the file. See openssl-env(7).

The list options -standard-commands, -digest-commands, and -cipher-commands output a list (one entry per line) of the names of all standard commands, message digest commands, or cipher commands, respectively, that are available.

The list parameters -cipher-algorithms, -digest-algorithms, and -mac-algorithms list all cipher, message digest, and message authentication code names, one entry per line. Aliases are listed as:

 from => to

The list parameter -public-key-algorithms lists all supported public key algorithms.

The command no-XXX tests whether a command of the specified name is available. If no command named XXX exists, it returns 0 (success) and prints no-XXX; otherwise it returns 1 and prints XXX. In both cases, the output goes to stdout and nothing is printed to stderr. Additional command line arguments are always ignored. Since for each cipher there is a command of the same name, this provides an easy way for shell scripts to test for the availability of ciphers in the openssl program. (no-XXX is not able to detect pseudo-commands such as quit, list, or no-XXX itself.)

Standard Commands

asn1parse

Parse an ASN.1 sequence.

ca

Certificate Authority (CA) Management.

ciphers

Cipher Suite Description Determination.

cms

CMS (Cryptographic Message Syntax) command.

crl

Certificate Revocation List (CRL) Management.

crl2pkcs7

CRL to PKCS#7 Conversion.

dgst

Message Digest calculation. MAC calculations are superseded by openssl-mac(1).

dhparam

Generation and Management of Diffie-Hellman Parameters. Superseded by openssl-genpkey(1) and openssl-pkeyparam(1).

dsa

DSA Data Management.

dsaparam

DSA Parameter Generation and Management. Superseded by openssl-genpkey(1) and openssl-pkeyparam(1).

ec

EC (Elliptic curve) key processing.

ecparam

EC parameter manipulation and generation.

enc

Encryption, decryption, and encoding.

engine

Engine (loadable module) information and manipulation.

errstr

Error Number to Error String Conversion.

fipsinstall

FIPS configuration installation.

gendsa

Generation of DSA Private Key from Parameters. Superseded by openssl-genpkey(1) and openssl-pkey(1).

genpkey

Generation of Private Key or Parameters.

genrsa

Generation of RSA Private Key. Superseded by openssl-genpkey(1).

help

Display information about a command's options.

info

Display diverse information built into the OpenSSL libraries.

kdf

Key Derivation Functions.

list

List algorithms and features.

mac

Message Authentication Code Calculation.

nseq

Create or examine a Netscape certificate sequence.

ocsp

Online Certificate Status Protocol command.

passwd

Generation of hashed passwords.

pkcs12

PKCS#12 Data Management.

pkcs7

PKCS#7 Data Management.

pkcs8

PKCS#8 format private key conversion command.

pkey

Public and private key management.

pkeyparam

Public key algorithm parameter management.

pkeyutl

Public key algorithm cryptographic operation command.

prime

Compute prime numbers.

provider

Load and query providers.

rand

Generate pseudo-random bytes.

rehash

Create symbolic links to certificate and CRL files named by the hash values.

req

PKCS#10 X.509 Certificate Signing Request (CSR) Management.

rsa

RSA key management.

rsautl

RSA command for signing, verification, encryption, and decryption. Superseded by openssl-pkeyutl(1).

s_client

This implements a generic SSL/TLS client which can establish a transparent connection to a remote server speaking SSL/TLS. It's intended for testing purposes only and provides only rudimentary interface functionality but internally uses mostly all functionality of the OpenSSL ssl library.

s_server

This implements a generic SSL/TLS server which accepts connections from remote clients speaking SSL/TLS. It's intended for testing purposes only and provides only rudimentary interface functionality but internally uses mostly all functionality of the OpenSSL ssl library. It provides both an own command line oriented protocol for testing SSL functions and a simple HTTP response facility to emulate an SSL/TLS-aware webserver.

s_time

SSL Connection Timer.

sess_id

SSL Session Data Management.

smime

S/MIME mail processing.

speed

Algorithm Speed Measurement.

spkac

SPKAC printing and generating command.

srp

Maintain SRP password file.

storeutl

Command to list and display certificates, keys, CRLs, etc.

ts

Time Stamping Authority command.

verify

X.509 Certificate Verification.

version

OpenSSL Version Information.

x509

X.509 Certificate Data Management.

Message Digest Commands

blake2b512

BLAKE2b-512 Digest

blake2s256

BLAKE2s-256 Digest

md2

MD2 Digest

md4

MD4 Digest

md5

MD5 Digest

mdc2

MDC2 Digest

rmd160

RMD-160 Digest

sha1

SHA-1 Digest

sha224

SHA-2 224 Digest

sha256

SHA-2 256 Digest

sha384

SHA-2 384 Digest

sha512

SHA-2 512 Digest

sha3-224

SHA-3 224 Digest

sha3-256

SHA-3 256 Digest

sha3-384

SHA-3 384 Digest

sha3-512

SHA-3 512 Digest

shake128

SHA-3 SHAKE128 Digest

shake256

SHA-3 SHAKE256 Digest

sm3

SM3 Digest

Encryption, Decryption, and Encoding Commands

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 openssl-enc(1) for more information.

aes128, aes-128-cbc, aes-128-cfb, aes-128-ctr, aes-128-ecb, aes-128-ofb

AES-128 Cipher

aes192, aes-192-cbc, aes-192-cfb, aes-192-ctr, aes-192-ecb, aes-192-ofb

AES-192 Cipher

aes256, aes-256-cbc, aes-256-cfb, aes-256-ctr, aes-256-ecb, aes-256-ofb

AES-256 Cipher

aria128, aria-128-cbc, aria-128-cfb, aria-128-ctr, aria-128-ecb, aria-128-ofb

Aria-128 Cipher

aria192, aria-192-cbc, aria-192-cfb, aria-192-ctr, aria-192-ecb, aria-192-ofb

Aria-192 Cipher

aria256, aria-256-cbc, aria-256-cfb, aria-256-ctr, aria-256-ecb, aria-256-ofb

Aria-256 Cipher

base64

Base64 Encoding

bf, bf-cbc, bf-cfb, bf-ecb, bf-ofb

Blowfish Cipher

camellia128, camellia-128-cbc, camellia-128-cfb, camellia-128-ctr, camellia-128-ecb, camellia-128-ofb

Camellia-128 Cipher

camellia192, camellia-192-cbc, camellia-192-cfb, camellia-192-ctr, camellia-192-ecb, camellia-192-ofb

Camellia-192 Cipher

camellia256, camellia-256-cbc, camellia-256-cfb, camellia-256-ctr, camellia-256-ecb, camellia-256-ofb

Camellia-256 Cipher

cast, cast-cbc

CAST Cipher

cast5-cbc, cast5-cfb, cast5-ecb, cast5-ofb

CAST5 Cipher

chacha20

Chacha20 Cipher

des, des-cbc, des-cfb, des-ecb, des-ede, des-ede-cbc, des-ede-cfb, des-ede-ofb, des-ofb

DES Cipher

des3, desx, des-ede3, des-ede3-cbc, des-ede3-cfb, des-ede3-ofb

Triple-DES Cipher

idea, idea-cbc, idea-cfb, idea-ecb, idea-ofb

IDEA Cipher

rc2, rc2-cbc, rc2-cfb, rc2-ecb, rc2-ofb

RC2 Cipher

rc4

RC4 Cipher

rc5, rc5-cbc, rc5-cfb, rc5-ecb, rc5-ofb

RC5 Cipher

seed, seed-cbc, seed-cfb, seed-ecb, seed-ofb

SEED Cipher

sm4, sm4-cbc, sm4-cfb, sm4-ctr, sm4-ecb, sm4-ofb

SM4 Cipher

OPTIONS

Details of which options are available depend on the specific command. This section describes some common options with common behavior.

Common Options

-help

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:

 openssl verify [flags...] -- -cert1.pem...

Format Options

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.

DER

A binary format, encoded or parsed according to Distinguished Encoding Rules (DER) of the ASN.1 data language.

ENGINE

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.

P12

A DER-encoded file containing a PKCS#12 object. It might be necessary to provide a decryption password to retrieve the private key.

PEM

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:

 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 ignored

The object-type must match the type of object that is expected. For example a BEGIN 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

The following legacy object-type's are also supported for compatibility with earlier releases:

 DSA PRIVATE KEY
 NEW CERTIFICATE REQUEST
 RSA PUBLIC KEY
 X509 CERTIFICATE
SMIME

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.

-inform format, -outform format

The format of the input or output streams.

-keyform format

Format of a private key input source.

-CRLform format

Format of a CRL input source.

Pass Phrase Options

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 passphrase-encoding(7).

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.

env:var

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.

file:pathname

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.

fd:number

Read the password from the file descriptor number. This can be used to send the data via a pipe for example.

stdin

Read the password from standard input.

Trusted Certificate Options

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/.

-CAfile file

Load the specified file which contains one or more PEM-format certificates of CA's that are trusted.

-no-CAfile

Do not load the default file of trusted certificates.

-CApath dir

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 openssl-rehash(1) for information on creating this type of directory.

-no-CApath

Do not use the default directory of trusted certificates.

-CAstore uri

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 file: scheme, this acts as -CAfile or -CApath, depending on if the URI indicates a single file or directory. See ossl_store-file(7) for more information on the file: scheme.

These certificates are also used when building the server certificate chain (for example with openssl-s_server(1)) or client certificate chain (for example with openssl-s_time(1)).

-no-CAstore

Do not use the default store.

Random State Options

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.

-rand files

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 ; for MS-Windows, , for OpenVMS, and : for all others. Another way to specify multiple files is to repeat this flag with different filenames.

-writerand file

Writes the seed data to the specified file upon exit. This file can be used in a subsequent command invocation.

Provider Options

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.

-provider name

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.

-provider_path path

Specify the search path that is used to locate provider modules. The format of path varies depending on the operating system being used.

Extended Verification Options

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.

-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.

-xkey infile, -xcert infile, -xchain

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.

-xcertform DER|PEM, -xkeyform DER|PEM

The input format for the extra certificate and key, respectively. See "Format Options" in openssl(1) for details.

-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.

-xcertform DER|PEM, -xkeyform DER|PEM

The input format for the extra certificate and key, respectively. See "Format Options" in openssl(1) for details.

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 "CERTIFICATE EXTENSIONS" in openssl-x509(1).

The third step is to check the trust settings on the root CA. The root CA should be trusted for the supplied purpose. For compatibility with previous versions of OpenSSL, a certificate with no trust settings is considered to be valid for all purposes.

The fourth, and final, step is to check the validity of the certificate chain. The validity period is checked against the system time and the notBefore and notAfter dates in the certificate. The certificate signatures are also checked at this point. The -attime flag may be used to specify a time other than "now."

If all operations complete successfully then certificate is considered valid. If any operation fails then the certificate is not valid.

The details of the processing steps can be fine-tuned with the following flags.

-verbose

Print extra information about the operations being performed.

-attime timestamp

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).

-no_check_time

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.

-x509_strict

This disables non-compliant workarounds for broken certificates.

-ignore_critical

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.

-issuer_checks

Ignored.

-crl_check

Checks end entity certificate validity by attempting to look up a valid CRL. If a valid CRL cannot be found an error occurs.

-crl_check_all

Checks the validity of all certificates in the chain by attempting to look up valid CRLs.

-use_deltas

Enable support for delta CRLs.

-extended_crl

Enable extended CRL features such as indirect CRLs and alternate CRL signing keys.

-suiteB_128_only, -suiteB_128, -suiteB_192

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.

-auth_level level

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 SSL_CTX_set_security_level(3) for the definitions of the available levels. The default security level is -1, or "not set". At security level 0 or lower all algorithms are acceptable. Security level 1 requires at least 80-bit-equivalent security and is broadly interoperable, though it will, for example, reject MD5 signatures or RSA keys shorter than 1024 bits.

-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.

-check_ss_sig

Verify the signature on the self-signed root CA. This is disabled by default because it doesn't add any security.

-allow_proxy_certs

Allow the verification of proxy certificates.

-trusted_first

As of OpenSSL 1.1.0 this option is on by default and cannot be disabled.

-no_alt_chains

As of OpenSSL 1.1.0, since -trusted_first always on, this option has no effect.

-trusted file

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 and -no-CApath options and it cannot be used with either the -CAfile or -CApath options, so only certificates in the file are trust anchors. This option may be used multiple times.

-untrusted file

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.

-policy arg

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.

-explicit_policy

Set policy variable require-explicit-policy (see RFC5280).

-policy_check

Enables certificate policy processing.

-policy_print

Print out diagnostics related to policy processing.

-inhibit_any

Set policy variable inhibit-any-policy (see RFC5280).

-inhibit_map

Set policy variable inhibit-policy-mapping (see RFC5280).

-purpose purpose

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.

-verify_depth num

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_email email

Verify if email matches the email address in Subject Alternative Name or the email in the subject Distinguished Name.

-verify_hostname hostname

Verify if hostname matches DNS name in Subject Alternative Name or Common Name in the subject certificate.

-verify_ip ip

Verify if ip matches the IP address in Subject Alternative Name of the subject certificate.

-verify_name name

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 openssl-x509(1). Supported policy names include: default, pkcs7, smime_sign, ssl_client, ssl_server. These mimics the combinations of purpose and trust settings used in SSL, CMS and S/MIME. As of OpenSSL 1.1.0, the trust model is inferred from the purpose when not specified, so the -verify_name options are functionally equivalent to the corresponding -purpose settings.

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, -, to turn it off. The default value is oneline. The first four are the most commonly used.

compat

Display the name using an old format from previous OpenSSL versions.

RFC2253

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.

oneline

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.

multiline

Display the name using multiple lines. It is equivalent to esc_ctrl, esc_msb, sep_multiline, space_eq, lname and align.

esc_2253

Escape the "special" characters in a field, as required by RFC 2253. That is, any of the characters ,+"<>;, # at the beginning of a string and leading or trailing spaces.

esc_2254

Escape the "special" characters in a field as required by RFC 2254 in a field. That is, the NUL character and and of ()*.

esc_ctrl

Escape non-printable ASCII characters, codes less than 0x20 (space) or greater than 0x7F (DELETE). They are displayed using RFC 2253 \XX notation where XX are the two hex digits representing the character value.

esc_msb

Escape any characters with the most significant bit set, that is with values larger than 127, as described in esc_ctrl.

use_quote

Escapes some characters by surrounding the entire string with quotation marks, ". Without this option, individual special characters are preceeded with a backslash character, \.

utf8

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 \UXXXX for 16 bits or \WXXXXXXXX for 32 bits. In addition, any UTF8Strings will be converted to their character form first.

ignore_type

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.

show_type

Display the type of the ASN1 character string before the value, such as BMPSTRING: Hello World.

dump_der

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_nostr

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

Dump all fields. When this used with dump_der, this allows the DER encoding of the structure to be unambiguously determined.

dump_unknown

Dump any field whose OID is not recognised by OpenSSL.

sep_comma_plus, sep_comma_plus_space, sep_semi_plus_space, sep_multiline

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.

dn_rev

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.

nofname, sname, lname, oid

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

Align field values for a more readable output. Only usable with sep_multiline.

space_eq

Places spaces round the equal sign, =, character which follows the field name.

TLS Version Options

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.

-ssl3, -tls1, -tls1_1, -tls1_2, -tls1_3, -no_ssl3, -no_tls1, -no_tls1_1, -no_tls1_2, -no_tls1_3

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.

-dtls, -dtls1, -dtls1_2

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.

Engine Options

-engine id

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 "Engine Configuration Module" in config(5).

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-engine(1), openssl-provider(1), openssl-rehash(1), and tsget(1).

For information about the use of environment variables in configuration, see "ENVIRONMENT" in config(5).

For information about querying or specifying CPU architecture flags, see OPENSSL_ia32cap(3), and OPENSSL_s390xcap(3).

For information about all environment variables used by the OpenSSL libraries, see openssl-env(7).

OPENSSL_TRACE=name[,...]

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:

TRACE

The tracing functionality.

TLS

General SSL/TLS.

TLS_CIPHER

SSL/TLS cipher.

ENGINE_CONF

ENGINE configuration.

ENGINE_TABLE

The function that is used by RSA, DSA (etc) code to select registered ENGINEs, cache defaults and functional references (etc), will generate debugging summaries.

ENGINE_REF_COUNT

Reference counts in the ENGINE structure will be monitored with a line of generated for each change.

PKCS5V2

PKCS#5 v2 keygen.

PKCS12_KEYGEN

PKCS#12 key generation.

PKCS12_DECRYPT

PKCS#12 decryption.

X509V3_POLICY

Generates the complete policy tree at various point during X.509 v3 policy evaluation.

BN_CTX

BIGNUM context.

SEE ALSO

openssl-asn1parse(1), openssl-ca(1), openssl-ciphers(1), openssl-cms(1), openssl-crl(1), openssl-crl2pkcs7(1), openssl-dgst(1), openssl-dhparam(1), openssl-dsa(1), openssl-dsaparam(1), openssl-ec(1), openssl-ecparam(1), openssl-enc(1), openssl-engine(1), openssl-errstr(1), openssl-gendsa(1), openssl-genpkey(1), openssl-genrsa(1), openssl-kdf(1), openssl-mac(1), openssl-nseq(1), openssl-ocsp(1), openssl-passwd(1), openssl-pkcs12(1), openssl-pkcs7(1), openssl-pkcs8(1), openssl-pkey(1), openssl-pkeyparam(1), openssl-pkeyutl(1), openssl-prime(1), openssl-rand(1), openssl-rehash(1), openssl-req(1), openssl-rsa(1), openssl-rsautl(1), openssl-s_client(1), openssl-s_server(1), openssl-s_time(1), openssl-sess_id(1), openssl-smime(1), openssl-speed(1), openssl-spkac(1), openssl-srp(1), openssl-storeutl(1), openssl-ts(1), openssl-verify(1), openssl-version(1), openssl-x509(1), config(5), crypto(7), openssl-env(7). ssl(7), x509v3_config(5)

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 2000-2019 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.