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 of RSA, DH and DSA key parameters
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
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-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.)
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.
Obsoleted by dhparam.
dsa
DSA Data Management.
dsaparam
DSA Parameter Generation.
enc
Encoding with Ciphers.
errstr
Error Number to Error String Conversion.
dhparam
Generation and Management of Diffie-Hellman Parameters.
gendh
Generation of Diffie-Hellman Parameters.
Obsoleted by dhparam.
RSA utility for signing, verification, encryption, and decryption.
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.
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
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
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 no-XXX pseudo-commands were added in OpenSSL 0.9.5a.
For notes on the availability of other commands, see their individual
manual pages.
