crypto: prng - Deterministic CPRNG

This patch adds a cryptographic pseudo-random number generator
based on CTR(AES-128).  It is meant to be used in cases where a
deterministic CPRNG is required.

One of the first applications will be as an input in the IPsec IV
generation process.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 795e31c..43b7473 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -666,6 +666,15 @@
 	help
 	  This is the LZO algorithm.
 
+comment "Random Number Generation"
+
+config CRYPTO_PRNG
+	tristate "Pseudo Random Number Generation for Cryptographic modules"
+	help
+	  This option enables the generic pseudo random number generator
+	  for cryptographic modules.  Uses the Algorithm specified in
+	  ANSI X9.31 A.2.4
+
 source "drivers/crypto/Kconfig"
 
 endif	# if CRYPTO