OpenSSL

Cryptography and SSL/TLS Toolkit

openssl

NAME

openssl - OpenSSL command line tool

SYNOPSIS

openssl command [ command_opts ... ] [ command_args ... ]

openssl list -standard-commands | -digest-commands | -cipher-commands | -cipher-algorithms | -digest-algorithms | -mac-algorithms | -public-key-algorithms

openssl no-XXX [ arbitrary 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 tool 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 sub-commands (command in the SYNOPSIS above), each of which often has a wealth of options and arguments (command_opts and command_args in the SYNOPSIS).

Detailed documentation and use cases for most standard subcommands are available (e.g., x509(1) or 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 environment variable OPENSSL_CONF can be used to specify the location of the file. If the environment variable is not specified, then the file is named openssl.cnf in the default certificate storage area, whose value depends on the configuration flags specified when the OpenSSL was built.

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 Sub-commands

asn1parse

Parse an ASN.1 sequence.

ca

Certificate Authority (CA) Management.

ciphers

Cipher Suite Description Determination.

cms

CMS (Cryptographic Message Syntax) utility.

crl

Certificate Revocation List (CRL) Management.

crl2pkcs7

CRL to PKCS#7 Conversion.

dgst

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 MAC calculations are superseded by openssl-mac(1).

dh

Diffie-Hellman Parameter Management. Obsoleted by openssl-dhparam(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

Encoding with Ciphers.

engine

Engine (loadable module) information and manipulation.

errstr

Error Number to Error String Conversion.

gendh

Generation of Diffie-Hellman Parameters. Obsoleted by openssl-dhparam(1).

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).

info

Display diverse information built into the OpenSSL libraries.

kdf

Key Derivation Functions.

mac

Message Authentication Code Calculation.

nseq

Create or examine a Netscape certificate sequence.

ocsp

Online Certificate Status Protocol utility.

passwd

Generation of hashed passwords.

pkcs12

PKCS#12 Data Management.

pkcs7

PKCS#7 Data Management.

pkcs8

PKCS#8 format private key conversion tool.

pkey

Public and private key management.

pkeyparam

Public key algorithm parameter management.

pkeyutl

Public key algorithm cryptographic operation utility.

prime

Compute prime numbers.

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 utility 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 utility.

srp

Maintain SRP password file.

storeutl

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

ts

Time Stamping Authority tool (client/server).

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

Encoding and Cipher 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 and command usage.

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...

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.

Random State Options

Prior to OpenSSL 3.0, 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 the appropriate CPU flags, device files, and so on. 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.

ENVIRONMENT

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), 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.

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.