[CRYPTO] sha256-generic: Extend sha256_generic.c to support SHA-224

Resubmitting this patch which extends sha256_generic.c to support SHA-224 as
described in FIPS 180-2 and RFC 3874. HMAC-SHA-224 as described in RFC4231
is then supported through the hmac interface.

Patch includes test vectors for SHA-224 and HMAC-SHA-224.

SHA-224 chould be chosen as a hash algorithm when 112 bits of security
strength is required.

Patch generated against the 2.6.24-rc1 kernel and tested against
2.6.24-rc1-git14 which includes fix for scatter gather implementation for HMAC.

Signed-off-by: Jonathan Lynch <jonathan.lynch@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 4 insertions, 1 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index cf115b14079e..7758454b9f17 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -91,7 +91,7 @@ config CRYPTO_SHA1
           SHA-1 secure hash standard (FIPS 180-1/DFIPS 180-2).
 
 config CRYPTO_SHA256
-        tristate "SHA256 digest algorithm"
+        tristate "SHA224 and SHA256 digest algorithm"
         select CRYPTO_ALGAPI
         help
           SHA256 secure hash standard (DFIPS 180-2).
@@ -99,6 +99,9 @@ config CRYPTO_SHA256
           This version of SHA implements a 256 bit hash with 128 bits of
           security against collision attacks.
 
+          This code also includes SHA-224, a 224 bit hash with 112 bits
+          of security against collision attacks.
+
 config CRYPTO_SHA512
         tristate "SHA384 and SHA512 digest algorithms"
         select CRYPTO_ALGAPI