Guide to configuring the linux kernel/crypto

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 * Guide to configuring the linux kernel

=Cryptographic options= config CRYPTO bool "Cryptographic API" help This option provides the core Cryptographic API.

config CRYPTO_HMAC bool "HMAC support" depends on CRYPTO help HMAC: Keyed-Hashing for Message Authentication (RFC2104). This is required for IPSec.

config CRYPTO_NULL tristate "Null algorithms" depends on CRYPTO help These are 'Null' algorithms, used by IPsec, which do nothing.

config CRYPTO_MD4 tristate "MD4 digest algorithm" depends on CRYPTO help MD4 message digest algorithm (RFC1320).

config CRYPTO_MD5 tristate "MD5 digest algorithm" depends on CRYPTO help MD5 message digest algorithm (RFC1321).

config CRYPTO_SHA1 tristate "SHA1 digest algorithm" depends on CRYPTO help SHA-1 secure hash standard (FIPS 180-1/DFIPS 180-2).

config CRYPTO_SHA1_Z990 tristate "SHA1 digest algorithm for IBM zSeries z990" depends on CRYPTO && ARCH_S390 help SHA-1 secure hash standard (FIPS 180-1/DFIPS 180-2).

config CRYPTO_SHA256 tristate "SHA256 digest algorithm" depends on CRYPTO help SHA256 secure hash standard (DFIPS 180-2). This version of SHA implements a 256 bit hash with 128 bits of security against collision attacks.

config CRYPTO_SHA512 tristate "SHA384 and SHA512 digest algorithms" depends on CRYPTO help SHA512 secure hash standard (DFIPS 180-2). This version of SHA implements a 512 bit hash with 256 bits of security against collision attacks.

This code also includes SHA-384, a 384 bit hash with 192 bits of security against collision attacks.

config CRYPTO_WP512 tristate "Whirlpool digest algorithms" depends on CRYPTO help Whirlpool hash algorithm 512, 384 and 256-bit hashes

Whirlpool-512 is part of the NESSIE cryptographic primitives. Whirlpool will be part of the ISO/IEC 10118-3:2003(E) standard

See also: 

config CRYPTO_TGR192 tristate "Tiger digest algorithms" depends on CRYPTO help Tiger hash algorithm 192, 160 and 128-bit hashes

Tiger is a hash function optimized for 64-bit processors while still having decent performance on 32-bit processors. Tiger was developed by Ross Anderson and Eli Biham.

See also: .

config CRYPTO_DES tristate "DES and Triple DES EDE cipher algorithms" depends on CRYPTO help DES cipher algorithm (FIPS 46-2), and Triple DES EDE (FIPS 46-3).

config CRYPTO_DES_Z990 tristate "DES and Triple DES cipher algorithms for IBM zSeries z990" depends on CRYPTO && ARCH_S390 help DES cipher algorithm (FIPS 46-2), and Triple DES EDE (FIPS 46-3).

config CRYPTO_BLOWFISH tristate "Blowfish cipher algorithm" depends on CRYPTO help Blowfish cipher algorithm, by Bruce Schneier. This is a variable key length cipher which can use keys from 32 bits to 448 bits in length. It's fast, simple and specifically designed for use on "large microprocessors". See also: 

config CRYPTO_TWOFISH tristate "Twofish cipher algorithm" depends on CRYPTO help Twofish cipher algorithm. Twofish was submitted as an AES (Advanced Encryption Standard) candidate cipher by researchers at CounterPane Systems. It is a	 16 round block cipher supporting key sizes of 128, 192, and 256 bits. See also: 

config CRYPTO_SERPENT tristate "Serpent cipher algorithm" depends on CRYPTO help Serpent cipher algorithm, by Anderson, Biham & Knudsen.

Keys are allowed to be from 0 to 256 bits in length, in steps of 8 bits. Also includes the 'Tnepres' algorithm, a reversed variant of Serpent for compatibility with old kerneli code.

See also: 

config CRYPTO_AES tristate "AES cipher algorithms" depends on CRYPTO && !(X86 || UML_X86) help AES cipher algorithms (FIPS-197). AES uses the Rijndael algorithm.

Rijndael appears to be consistently a very good performer in	 both hardware and software across a wide range of computing environments regardless of its use in feedback or non-feedback modes. Its key setup time is excellent, and its key agility is good. Rijndael's very low memory requirements make it very well suited for restricted-space environments, in which it also demonstrates excellent performance. Rijndael's operations are among the easiest to defend against power and timing attacks.

The AES specifies three key sizes: 128, 192 and 256 bits

See  for more information.

config CRYPTO_AES_586 tristate "AES cipher algorithms (i586)" depends on CRYPTO && ((X86 || UML_X86) && !64BIT) help AES cipher algorithms (FIPS-197). AES uses the Rijndael algorithm.

Rijndael appears to be consistently a very good performer in	 both hardware and software across a wide range of computing environments regardless of its use in feedback or non-feedback modes. Its key setup time is excellent, and its key agility is good. Rijndael's very low memory requirements make it very well suited for restricted-space environments, in which it also demonstrates excellent performance. Rijndael's operations are among the easiest to defend against power and timing attacks.

The AES specifies three key sizes: 128, 192 and 256 bits

See  for more information.

config CRYPTO_AES_X86_64 tristate "AES cipher algorithms (x86_64)" depends on CRYPTO && ((X86 || UML_X86) && 64BIT) help AES cipher algorithms (FIPS-197). AES uses the Rijndael algorithm.

Rijndael appears to be consistently a very good performer in	 both hardware and software across a wide range of computing environments regardless of its use in feedback or non-feedback modes. Its key setup time is excellent, and its key agility is good. Rijndael's very low memory requirements make it very well suited for restricted-space environments, in which it also demonstrates excellent performance. Rijndael's operations are among the easiest to defend against power and timing attacks.

The AES specifies three key sizes: 128, 192 and 256 bits

See  for more information.

config CRYPTO_CAST5 tristate "CAST5 (CAST-128) cipher algorithm" depends on CRYPTO help The CAST5 encryption algorithm (synonymous with CAST-128) is described in RFC2144.

config CRYPTO_CAST6 tristate "CAST6 (CAST-256) cipher algorithm" depends on CRYPTO help The CAST6 encryption algorithm (synonymous with CAST-256) is described in RFC2612.

config CRYPTO_TEA tristate "TEA, XTEA and XETA cipher algorithms" depends on CRYPTO help TEA cipher algorithm.

Tiny Encryption Algorithm is a simple cipher that uses many rounds for security. It is very fast and uses little memory.

Xtendend Tiny Encryption Algorithm is a modification to	 the TEA algorithm to address a potential key weakness in the TEA algorithm.

Xtendend Encryption Tiny Algorithm is a mis-implementation of the XTEA algorithm for compatibility purposes.

config CRYPTO_ARC4 tristate "ARC4 cipher algorithm" depends on CRYPTO help ARC4 cipher algorithm.

ARC4 is a stream cipher using keys ranging from 8 bits to 2048 bits in length. This algorithm is required for driver-based WEP, but it should not be for other purposes because of the weakness of the algorithm.

config CRYPTO_KHAZAD tristate "Khazad cipher algorithm" depends on CRYPTO help Khazad cipher algorithm.

Khazad was a finalist in the initial NESSIE competition. It is	 an algorithm optimized for 64-bit processors with good performance on 32-bit processors. Khazad uses an 128 bit key size.

See also: 

config CRYPTO_ANUBIS tristate "Anubis cipher algorithm" depends on CRYPTO help Anubis cipher algorithm.

Anubis is a variable key length cipher which can use keys from 128 bits to 320 bits in length. It was evaluated as a entrant in the NESSIE competition. See also:  

config CRYPTO_DEFLATE tristate "Deflate compression algorithm" depends on CRYPTO select ZLIB_INFLATE select ZLIB_DEFLATE help This is the Deflate algorithm (RFC1951), specified for use in IPSec with the IPCOMP protocol (RFC3173, RFC2394). You will most probably want this if using IPSec.

config CRYPTO_MICHAEL_MIC tristate "Michael MIC keyed digest algorithm" depends on CRYPTO help Michael MIC is used for message integrity protection in TKIP (IEEE 802.11i). This algorithm is required for TKIP, but it	 should not be used for other purposes because of the weakness of the algorithm.

config CRYPTO_CRC32C tristate "CRC32c CRC algorithm" depends on CRYPTO select LIBCRC32C help Castagnoli, et al Cyclic Redundancy-Check Algorithm. Used by iSCSI for header and data digests and by others. See Castagnoli93. This implementation uses lib/libcrc32c. Module will be crc32c.

config CRYPTO_TEST tristate "Testing module" depends on CRYPTO help Quick & dirty crypto test module.

source "drivers/crypto/Kconfig" endmenu