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
o Encryption and Decryption with Ciphers
o SSL/TLS Client and Server Tests
o Handling of S/MIME signed or encrypted mail
o Time Stamp requests, generation and verification
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 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 parameters 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 in the present openssl utility.
The list parameters cipher-algorithms and
digest-algorithms list all cipher and message digest 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.)
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.
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.
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).
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.
The list-XXX-algorithms pseudo-commands were added in OpenSSL 1.0.0;
For notes on the availability of other commands, see their individual
manual pages.
Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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.