A modern CBC-MAC variant that avoids the security problems of plain CBC-MAC. Approved by NIST. Also sometimes called OMAC.

GMAC is related to the GCM authenticated cipher mode. It is quite slow unless hardware support for carryless multiplications is available. A new nonce must be used with each message authenticated, or otherwise all security is lost.

An older authentication code based on a block cipher. Serious security problems, in particular insecure if messages of several different lengths are authenticated. Avoid unless required for compatibility.

A message authentication code based on a hash function. Very commonly used.

A polynomial mac (similar to GMAC). Very fast, but tricky to use safely. Forms part of the ChaCha20Poly1305 AEAD mode. A new key must be used for each message, or all security is lost.

A modern and very fast PRF. Produces only a 64-bit output. Defaults to “SipHash(2,4)” which is the recommended configuration, using 2 rounds for each input block and 4 rounds for finalization.

A CBC-MAC variant sometimes used in finance. Always uses DES. Sometimes called the “DES retail MAC”, also standardized in ISO 9797-1. It is slow and has known attacks. Avoid unless required.

A recently designed hash function. Very fast on 64-bit processors. Can output a hash of any length between 1 and 64 bytes, this is specified by passing desired byte length.

Alias for Blake2b 32

Alias for Blake2b 64

An older (and incompatible) variant of SHA-3, but sometimes used. Prefer SHA-3 in new code.

An old hash function that is now known to be trivially breakable. It is very fast, and may still be suitable as a (non-cryptographic) checksum.

Widely used, now known to be broken.

A 160 bit hash function, quite old but still thought to be secure (up to the limit of 2**80 computation required for a collision which is possible with any 160 bit hash function). Somewhat deprecated these days.

Widely adopted NSA designed hash function. Starting to show significant signs of weakness, and collisions can now be generated. Avoid in new designs.

Relatively fast 256 bit hash function, thought to be secure. Also includes the variant SHA-224. There is no real reason to use SHA-224.

SHA-512 is faster than SHA-256 on 64-bit processors. Also includes the truncated variants SHA-384 and SHA-512/256, which have the advantage of avoiding message extension attacks.

The new NIST standard hash. Fairly slow. Supports 224, 256, 384 or 512 bit outputs. SHA-3 is faster with smaller outputs. Use as “SHA3_256” or “SHA3_512”. Plain “SHA-3” selects default 512 bit output.

These are actually XOFs (extensible output functions) based on SHA-3, which can output a value of any byte length. For example “SHAKE128 @128” will produce 1024 bits of output.

Chinese national hash function, 256 bit output. Widely used in industry there. Fast and seemingly secure, but no reason to prefer it over SHA-2 or SHA-3 unless required.

A contender for the NIST SHA-3 competition. Very fast on 64-bit systems. Can output a hash of any length between 1 and 64 bytes. It also accepts an optional “personalization string” which can create variants of the hash. This is useful for domain separation.

Newly designed Russian national hash function. Due to use of input-dependent table lookups, it is vulnerable to side channels. There is no reason to use it unless compatibility is needed. Warning: The Streebog Sbox has recently been revealed to have a hidden structure which interacts with its linear layer in a way which may provide a backdoor when used in certain ways. Avoid Streebog if at all possible.

A 512-bit hash function standardized by ISO and NESSIE. Relatively slow, and due to the table based implementation it is potentially vulnerable to cache based side channels.

Parallel simply concatenates multiple hash functions. For example “Parallel SHA256 SHA512 outputs a 256+512 bit hash created by hashing the input with both SHA256 and SHA512 and concatenating the outputs.

This combines two cryptographic hashes in such a way that preimage and collision attacks are provably at least as hard as a preimage or collision attack on the strongest hash.

Checksums, not suitable for cryptographic use, but can be used for error checking purposes.

AES

Comes in three variants, AES-128, AES-192, and AES-256. The standard 128-bit block cipher. Many modern platforms offer hardware acceleration. However, on platforms without hardware support, AES implementations typically are vulnerable to side channel attacks. For x86 systems with SSSE3 but without AES-NI, Botan has an implementation which avoids known side channels.

ARIA

South Korean cipher used in industry there. No reason to use it otherwise.

Blowfish

A 64-bit cipher popular in the pre-AES era. Very slow key setup. Also used (with bcrypt) for password hashing.

Camellia

Comes in three variants, Camellia-128, Camellia-192, and Camellia-256. A Japanese design standardized by ISO, NESSIE and CRYPTREC. Rarely used outside of Japan.

Cascade

Creates a block cipher cascade, where each block is encrypted by two ciphers with independent keys. Useful if you're very paranoid. In practice any single good cipher (such as Serpent, SHACAL2, or AES-256) is more than sufficient.

Please set a key with size = max_key_size_A + max_key_size_B.

CAST-128

A 64-bit cipher, commonly used in OpenPGP.

CAST-256

A 128-bit cipher that was a contestant in the NIST AES competition. Almost never used in practice. Prefer AES or Serpent. Warning: Support for CAST-256 is deprecated and will be removed in a future major release.

DES, 3DES, DESX

Originally designed by IBM and NSA in the 1970s. Today, DES's 56-bit key renders it insecure to any well-resourced attacker. DESX and 3DES extend the key length, and are still thought to be secure, modulo the limitation of a 64-bit block. All are somewhat common in some industries such as finance. Avoid in new code. Warning: Support for DESX is deprecated and it will be removed in a future major release.

IDEA

An older but still unbroken 64-bit cipher with a 128-bit key. Somewhat common due to its use in PGP. Avoid in new designs.

Kasumi

A 64-bit cipher used in 3GPP mobile phone protocols. There is no reason to use it outside of this context. Warning: Support for Kasumi is deprecated and will be removed in a future major release.

Lion

A "block cipher construction" which can encrypt blocks of nearly arbitrary length. Built from a stream cipher and a hash function. Useful in certain protocols where being able to encrypt large or arbitrary length blocks is necessary.

MISTY1

A 64-bit Japanese cipher standardized by NESSIE and ISO. Seemingly secure, but quite slow and saw little adoption. No reason to use it in new code. Warning: Support for MISTY1 is deprecated and will be removed in a future major release.

Noekeon

A fast 128-bit cipher by the designers of AES. Easily secured against side channels.

SEED

A older South Korean cipher, widely used in industry there. No reason to choose it otherwise.

Serpent

An AES contender. Widely considered the most conservative design. Fairly slow unless SIMD instructions are available.

SHACAL2

The 256-bit block cipher used inside SHA-256. Accepts up to a 512-bit key. Fast, especially when SIMD or SHA-2 acceleration instructions are available. Standardized by NESSIE but otherwise obscure.

Twofish

A 128-bit block cipher that was one of the AES finalists. Has a somewhat complicated key setup and a "kitchen sink" design.

SM4

A 128-bit Chinese national cipher, required for use in certain commercial applications in China. Quite slow. Probably no reason to use it outside of legal requirements.

Threefish-512

A 512-bit tweakable block cipher that was used in the Skein hash function. Very fast on 64-bit processors.

XTEA

A 64-bit cipher popular for its simple implementation. Avoid in new code.