`openssl`

Command-line tool for using the OpenSSL crypto library

Syntax:

openssl command [command_opts] [command_args]

openssl [list-standard-commands |
        list-message-digest-commands |
        list-cipher-commands |
        list-cipher-algorithms |
        list-message-digest-algorithms |
        list-public-key-algorithms]

openssl no-cmd [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 that they require.

The openssl program is a command-line tool for using the various cryptography functions of OpenSSL's crypto library from the shell. You can use it for the following:

creation and management of private keys, public keys and parameters
public key cryptographic operations
creation of X.509 certificates, CSRs and CRLs
calculation of Message Digests
encryption and Decryption with Ciphers
SSL/TLS Client and Server Tests
handling of S/MIME signed or encrypted mail
timestamp requests, generation and verification

Command summary

The openssl program provides a rich variety of commands (command in the synopsis above), each of which often has a wealth of options and arguments (command_opts and command_args).

The pseudo-commands list-standard-commands, list-message-digest-commands, and list-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 in the present openssl utility.

The pseudo-commands list-cipher-algorithms and list-message-digest-algorithms list all cipher and message digest names, one entry per line. Aliases are listed as:

from => to

The pseudo-command list-public-key-algorithms lists all supported public key algorithms.

The pseudo-command no-cmd tests whether a command of the specified name is available. If no command named cmd exists, openssl returns 0 (success) and prints no-cmd; otherwise it returns 1 and prints cmd. 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's 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. (The no-cmd can't detect pseudo-commands such as quit, list-...-commands, or no-cmd itself.)

Standard commands

asn1parse: Parse an ASN.1 sequence.
ca: Certificate Authority (CA) Management.
ciphers: Cipher Suite Description Determination.
crl: Certificate Revocation List (CRL) Management.
crl2pkcs7: CRL to PKCS#7 Conversion.
dgst: Message Digest Calculation.
dh: Diffie-Hellman Parameter Management; rendered obsolete by dhparam.
dsa: DSA Data Management.
dsaparam: DSA Parameter Generation and Management. Superseded by genpkey and pkeyparam.
enc: Encoding with Ciphers.
errstr: Error Number to Error String Conversion.
dhparam: Generation and Management of Diffie-Hellman Parameters. Superseded by genpkey and pkeyparam.
gendh: Generation of Diffie-Hellman Parameters; rendered obsolete by dhparam.
gendsa: Generation of DSA Private Key from Parameters. Superseded by genpkey and pkey.
genpkey: Generation of Private Key or Parameters.
genrsa: Generation of RSA Private Key. Superseded by genpkey.
ocsp: Online Certificate Status Protocol utility.
passwd: Generation of hashed passwords.
pkcs12: PKCS#12 Data Management.
pkcs7: PKCS#7 Data Management.
pkey: Public and private key management.
pkeyutl: Public key algorithm cryptographic operation utility.
pkeyparam: Public key algorithm parameter management.
rand: Generate pseudo-random bytes.
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 pkeyutl.
s_client: This implements a generic SSL/TLS client that 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 that 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 its 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.
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

md2: MD2 Digest.
md5: MD5 Digest.
mdc2: MDC2 Digest.
rmd160: RMD-160 Digest.
sha: SHA Digest.
sha1: SHA-1 Digest.
sha224: SHA-224 Digest.
sha256: SHA-256 Digest.
sha384: SHA-384 Digest.
sha512: SHA-512 Digest.

Encoding and cipher commands

base64: Base64 Encoding.
bf, bf-cbc, bf-cfb, bf-ecb, bf-ofb: Blowfish Cipher.
cast, cast-cbc: CAST Cipher.
cast5-cbc, cast5-cfb, cast5-ecb, cast5-ofb: CAST5 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.

Pass phrase arguments

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, you're prompted to enter one: this will typically be read from the current terminal with echoing turned off.

pass:password: The actual password is password. Since the password is visible to utilities, you should use this form only where security isn't important.
env:var: Obtain the password from the environment variable var. Since the environment of other processes is visible on certain platforms, you should use this option with caution.
file:pathname: The first line of pathname is the password. If you supply the same pathname argument to -passin and -passout arguments, the first line is used for the input password, and the next line for the output password. The 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 given file descriptor number. You can use this, for example, to send the data via a pipe.
stdin: Read the password from standard input.

Exit status:

0: Success.
1: An error occurred.