NAME

LIBRARY

SYNOPSIS

DESCRIPTION

COMMAND OPTIONS

-v

Verbose option. List ciphers with a complete description of protocol version (SSLv2 or SSLv3; the latter includes TLS), key exchange, authentication, encryption and mac algorithms used along with any key size restrictions and whether the algorithm is classed as an "export" cipher. Note that without the -v option, ciphers may seem to appear twice in a cipher list; this is when similar ciphers are available for SSL v2 and for SSL v3/TLS v1.

-V

Like -v, but include cipher suite codes in output (hex format).

-ssl3

only include SSL v3 ciphers.

-ssl2

only include SSL v2 ciphers.

-tls1

only include TLS v1 ciphers.

-h, -?

print a brief usage message.

cipherlist

a cipher list to convert to a cipher preference list. If it is not included then the default cipher list will be used. The format is described below.

CIPHER LIST FORMAT

The actual cipher string can take several different forms.

It can consist of a single cipher suite such as RC4-SHA.

It can represent a list of cipher suites containing a certain algorithm, or cipher suites of a certain type. For example SHA1 represents all ciphers suites using the digest algorithm SHA1 and SSLv3 represents all SSL v3 algorithms.

Lists of cipher suites can be combined in a single cipher string using the + character. This is used as a logical and operation. For example SHA1+DES represents all cipher suites containing the SHA1 and the DES algorithms.

Each cipher string can be optionally preceded by the characters !, - or +.

If ! is used then the ciphers are permanently deleted from the list. The ciphers deleted can never reappear in the list even if they are explicitly stated.

If - is used then the ciphers are deleted from the list, but some or all of the ciphers can be added again by later options.

If + is used then the ciphers are moved to the end of the list. This option doesn't add any new ciphers it just moves matching existing ones.

If none of these characters is present then the string is just interpreted as a list of ciphers to be appended to the current preference list. If the list includes any ciphers already present they will be ignored: that is they will not moved to the end of the list.

Additionally the cipher string @STRENGTH can be used at any point to sort the current cipher list in order of encryption algorithm key length.

CIPHER STRINGS

DEFAULT

the default cipher list. This is determined at compile time and is normally ALL:!EXPORT:!aNULL:!eNULL:!SSLv2. This must be the firstcipher string specified.

COMPLEMENTOFDEFAULT

the ciphers included in ALL, but not enabled by default. Currently this is ADH and AECDH. Note that this rule does not cover eNULL, which is not included by ALL (use COMPLEMENTOFALL if necessary).

ALL

all cipher suites except the eNULL ciphers which must be explicitly enabled; as of OpenSSL, the ALL cipher suites are reasonably ordered by default

COMPLEMENTOFALL

the cipher suites not enabled by ALL, currently being eNULL.

HIGH

"high" encryption cipher suites. This currently means those with key lengths larger than 128 bits, and some cipher suites with 128-bit keys.

MEDIUM

"medium" encryption cipher suites, currently some of those using 128 bit encryption.

LOW

"low" encryption cipher suites, currently those using 64 or 56 bit encryption algorithms but excluding export cipher suites.

EXP, EXPORT

export encryption algorithms. Including 40 and 56 bits algorithms.

EXPORT40

40 bit export encryption algorithms

EXPORT56

56 bit export encryption algorithms. In OpenSSL 0.9.8c and later the set of 56 bit export ciphers is empty unless OpenSSL has been explicitly configured with support for experimental ciphers.

eNULL, NULL

the "NULL" ciphers that is those offering no encryption. Because these offer no encryption at all and are a security risk they are disabled unless explicitly included.

aNULL

the cipher suites offering no authentication. This is currently the anonymous DH algorithms and anonymous ECDH algorithms. These cipher suites are vulnerable to a "man in the middle" attack and so their use is normally discouraged.

kRSA, RSA

cipher suites using RSA key exchange.

kDHr, kDHd, kDH

cipher suites using DH key agreement and DH certificates signed by CAs with RSA and DSS keys or either respectively. Not implemented.

kEDH

cipher suites using ephemeral DH key agreement, including anonymous cipher suites.

EDH

cipher suites using authenticated ephemeral DH key agreement.

ADH

anonymous DH cipher suites, note that this does not include anonymous Elliptic Curve DH (ECDH) cipher suites.

DH

cipher suites using DH, including anonymous DH, ephemeral DH and fixed DH.

kECDHr, kECDHe, kECDH

cipher suites using fixed ECDH key agreement signed by CAs with RSA and ECDSA keys or either respectively.

kEECDH

cipher suites using ephemeral ECDH key agreement, including anonymous cipher suites.

EECDHE

cipher suites using authenticated ephemeral ECDH key agreement.

AECDH

anonymous Elliptic Curve Diffie Hellman cipher suites.

ECDH

cipher suites using ECDH key exchange, including anonymous, ephemeral and fixed ECDH.

aRSA

cipher suites using RSA authentication, i.e. the certificates carry RSA keys.

aDSS, DSS

cipher suites using DSS authentication, i.e. the certificates carry DSS keys.

aDH

cipher suites effectively using DH authentication, i.e. the certificates carry DH keys. Not implemented.

aECDH

cipher suites effectively using ECDH authentication, i.e. the certificates carry ECDH keys.

aECDSA, ECDSA

cipher suites using ECDSA authentication, i.e. the certificates carry ECDSA keys.

kFZA, aFZA, eFZA, FZA

ciphers suites using FORTEZZA key exchange, authentication, encryption or all FORTEZZA algorithms. Not implemented.

TLSv1.2, TLSv1, SSLv3, SSLv2

TLS v1.2, TLS v1.0, SSL v3.0 or SSL v2.0 cipher suites respectively. Note: there are no ciphersuites specific to TLS v1.1.

AES128, AES256, AES

cipher suites using 128 bit AES, 256 bit AES or either 128 or 256 bit AES.

AESGCM

AES in Galois Counter Mode (GCM): these ciphersuites are only supported in TLS v1.2.

CAMELLIA128, CAMELLIA256, CAMELLIA

cipher suites using 128 bit CAMELLIA, 256 bit CAMELLIA or either 128 or 256 bit CAMELLIA.

3DES

cipher suites using triple DES.

DES

cipher suites using DES (not triple DES).

RC4

cipher suites using RC4.

RC2

cipher suites using RC2.

IDEA

cipher suites using IDEA.

SEED

cipher suites using SEED.

MD5

cipher suites using MD5.

SHA1, SHA

cipher suites using SHA1.

SHA256, SHA384

ciphersuites using SHA256 or SHA384.

aGOST

cipher suites using GOST R 34.10 (either 2001 or 94) for authenticaction (needs an engine supporting GOST algorithms).

aGOST01

cipher suites using GOST R 34.10-2001 authentication.

aGOST94

cipher suites using GOST R 34.10-94 authentication (note that R 34.10-94 standard has been expired so use GOST R 34.10-2001)

kGOST

cipher suites, using VKO 34.10 key exchange, specified in the RFC 4357.

GOST94

cipher suites, using HMAC based on GOST R 34.11-94.

GOST89MAC

cipher suites using GOST 28147-89 MAC instead of HMAC.

PSK

cipher suites using pre-shared keys (PSK).

CIPHER SUITE NAMES

NOTES

Some compiled versions of OpenSSL may not include all the ciphers listed here because some ciphers were excluded at compile time.

EXAMPLES

openssl ciphers -v 'ALL:eNULL'

Include all ciphers except NULL and anonymous DH then sort by strength:

openssl ciphers -v 'ALL:!ADH:@STRENGTH'

Include all ciphers except ones with no encryption (eNULL) or no authentication (aNULL):

openssl ciphers -v 'ALL:!aNULL'

Include only 3DES ciphers and then place RSA ciphers last:

openssl ciphers -v '3DES:+RSA'

Include all RC4 ciphers but leave out those without authentication:

openssl ciphers -v 'RC4:!COMPLEMENTOFDEFAULT'

Include all chiphers with RSA authentication but leave out ciphers without encryption.

openssl ciphers -v 'RSA:!COMPLEMENTOFALL'

SEE ALSO

HISTORY