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
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 in the SYNOPSIS).
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-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-...-commands, 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.
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.
The openssl(1) document appeared in OpenSSL 0.9.2. The list-XXX-commands pseudo-commands were added in
OpenSSL 0.9.3; The list-XXX-algorithms pseudo-commands were added in
OpenSSL 1.0.0; the no-XXX pseudo-commands were added in OpenSSL
0.9.5a. For notes on the availability of other commands, see their
individual manual pages.
