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, as of OpenSSL 1.0.0, is normally ALL:!aNULL:!eNULL. This must be the first cipher string specified.

COMPLEMENTOFDEFAULT

the ciphers included in ALL, but not enabled by default. Currently this is ADH. 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. 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.

kEDH

cipher suites using ephemeral DH key agreement.

kDHr, kDHd

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

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.

kFZA, aFZA, eFZA, FZA

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

TLSv1, SSLv3, SSLv2

TLS v1.0, SSL v3.0 or SSL v2.0 cipher suites respectively.

DH

cipher suites using DH, including anonymous DH.

ADH

anonymous DH cipher suites.

AES

cipher suites using AES.

CAMELLIA

cipher suites using 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.

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.

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 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