--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/prngs/yarrow.c	Sat Mar 25 12:59:58 2006 +0000
@@ -0,0 +1,317 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://libtomcrypt.org
+ */
+#include "tomcrypt.h"
+
+/**
+  @file yarrow.c
+  Yarrow PRNG, Tom St Denis
+*/  
+
+#ifdef YARROW
+
+const struct ltc_prng_descriptor yarrow_desc =
+{
+    "yarrow", 64,
+    &yarrow_start,
+    &yarrow_add_entropy,
+    &yarrow_ready,
+    &yarrow_read,
+    &yarrow_done,
+    &yarrow_export,
+    &yarrow_import,
+    &yarrow_test
+};
+
+/**
+  Start the PRNG
+  @param prng     [out] The PRNG state to initialize
+  @return CRYPT_OK if successful
+*/  
+int yarrow_start(prng_state *prng)
+{
+   int err;
+   
+   LTC_ARGCHK(prng != NULL);
+
+   /* these are the default hash/cipher combo used */
+#ifdef RIJNDAEL
+#if    YARROW_AES==0
+   prng->yarrow.cipher = register_cipher(&rijndael_enc_desc);
+#elif  YARROW_AES==1
+   prng->yarrow.cipher = register_cipher(&aes_enc_desc);
+#elif  YARROW_AES==2
+   prng->yarrow.cipher = register_cipher(&rijndael_desc);
+#elif  YARROW_AES==3
+   prng->yarrow.cipher = register_cipher(&aes_desc);
+#endif
+#elif defined(BLOWFISH)
+   prng->yarrow.cipher = register_cipher(&blowfish_desc);
+#elif defined(TWOFISH)
+   prng->yarrow.cipher = register_cipher(&twofish_desc);
+#elif defined(RC6)
+   prng->yarrow.cipher = register_cipher(&rc6_desc);
+#elif defined(RC5)
+   prng->yarrow.cipher = register_cipher(&rc5_desc);
+#elif defined(SAFERP)
+   prng->yarrow.cipher = register_cipher(&saferp_desc);
+#elif defined(RC2)
+   prng->yarrow.cipher = register_cipher(&rc2_desc);
+#elif defined(NOEKEON)   
+   prng->yarrow.cipher = register_cipher(&noekeon_desc);
+#elif defined(CAST5)
+   prng->yarrow.cipher = register_cipher(&cast5_desc);
+#elif defined(XTEA)
+   prng->yarrow.cipher = register_cipher(&xtea_desc);
+#elif defined(SAFER)
+   prng->yarrow.cipher = register_cipher(&safer_sk128_desc);
+#elif defined(DES)
+   prng->yarrow.cipher = register_cipher(&des3_desc);
+#else
+   #error YARROW needs at least one CIPHER
+#endif
+   if ((err = cipher_is_valid(prng->yarrow.cipher)) != CRYPT_OK) {
+      return err;
+   }
+
+#ifdef SHA256
+   prng->yarrow.hash   = register_hash(&sha256_desc);
+#elif defined(SHA512)
+   prng->yarrow.hash   = register_hash(&sha512_desc);
+#elif defined(TIGER)
+   prng->yarrow.hash   = register_hash(&tiger_desc);
+#elif defined(SHA1)
+   prng->yarrow.hash   = register_hash(&sha1_desc);
+#elif defined(RIPEMD160)
+   prng->yarrow.hash   = register_hash(&rmd160_desc);
+#elif defined(RIPEMD128)
+   prng->yarrow.hash   = register_hash(&rmd128_desc);
+#elif defined(MD5)
+   prng->yarrow.hash   = register_hash(&md5_desc);
+#elif defined(MD4)
+   prng->yarrow.hash   = register_hash(&md4_desc);
+#elif defined(MD2)
+   prng->yarrow.hash   = register_hash(&md2_desc);
+#elif defined(WHIRLPOOL)
+   prng->yarrow.hash   = register_hash(&whirlpool_desc);
+#else
+   #error YARROW needs at least one HASH
+#endif
+   if ((err = hash_is_valid(prng->yarrow.hash)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* zero the memory used */
+   zeromem(prng->yarrow.pool, sizeof(prng->yarrow.pool));
+
+   return CRYPT_OK;
+}
+
+/**
+  Add entropy to the PRNG state
+  @param in       The data to add
+  @param inlen    Length of the data to add
+  @param prng     PRNG state to update
+  @return CRYPT_OK if successful
+*/  
+int yarrow_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng)
+{
+   hash_state md;
+   int err;
+
+   LTC_ARGCHK(in  != NULL);
+   LTC_ARGCHK(prng != NULL);
+
+   if ((err = hash_is_valid(prng->yarrow.hash)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* start the hash */
+   if ((err = hash_descriptor[prng->yarrow.hash].init(&md)) != CRYPT_OK) {
+      return err; 
+   }
+
+   /* hash the current pool */
+   if ((err = hash_descriptor[prng->yarrow.hash].process(&md, prng->yarrow.pool, 
+                                                        hash_descriptor[prng->yarrow.hash].hashsize)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* add the new entropy */
+   if ((err = hash_descriptor[prng->yarrow.hash].process(&md, in, inlen)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* store result */
+   if ((err = hash_descriptor[prng->yarrow.hash].done(&md, prng->yarrow.pool)) != CRYPT_OK) {
+      return err;
+   }
+
+   return CRYPT_OK;
+}
+
+/**
+  Make the PRNG ready to read from
+  @param prng   The PRNG to make active
+  @return CRYPT_OK if successful
+*/  
+int yarrow_ready(prng_state *prng)
+{
+   int ks, err;
+
+   LTC_ARGCHK(prng != NULL);
+
+   if ((err = hash_is_valid(prng->yarrow.hash)) != CRYPT_OK) {
+      return err;
+   }
+   
+   if ((err = cipher_is_valid(prng->yarrow.cipher)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* setup CTR mode using the "pool" as the key */
+   ks = (int)hash_descriptor[prng->yarrow.hash].hashsize;
+   if ((err = cipher_descriptor[prng->yarrow.cipher].keysize(&ks)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((err = ctr_start(prng->yarrow.cipher,     /* what cipher to use */
+                        prng->yarrow.pool,       /* IV */
+                        prng->yarrow.pool, ks,   /* KEY and key size */
+                        0,                       /* number of rounds */
+                        CTR_COUNTER_LITTLE_ENDIAN, /* little endian counter */
+                        &prng->yarrow.ctr)) != CRYPT_OK) {
+      return err;
+   }
+   return CRYPT_OK;
+}
+
+/**
+  Read from the PRNG
+  @param out      Destination
+  @param outlen   Length of output
+  @param prng     The active PRNG to read from
+  @return Number of octets read
+*/  
+unsigned long yarrow_read(unsigned char *out, unsigned long outlen, prng_state *prng)
+{
+   LTC_ARGCHK(out  != NULL);
+   LTC_ARGCHK(prng != NULL);
+
+   /* put out in predictable state first */
+   zeromem(out, outlen);
+   
+   /* now randomize it */
+   if (ctr_encrypt(out, out, outlen, &prng->yarrow.ctr) != CRYPT_OK) {
+      return 0;
+   }
+   return outlen;
+}
+
+/**
+  Terminate the PRNG
+  @param prng   The PRNG to terminate
+  @return CRYPT_OK if successful
+*/  
+int yarrow_done(prng_state *prng)
+{
+   LTC_ARGCHK(prng != NULL);
+
+   /* call cipher done when we invent one ;-) */
+
+   /* we invented one */
+   return ctr_done(&prng->yarrow.ctr);
+}
+
+/**
+  Export the PRNG state
+  @param out       [out] Destination
+  @param outlen    [in/out] Max size and resulting size of the state
+  @param prng      The PRNG to export
+  @return CRYPT_OK if successful
+*/  
+int yarrow_export(unsigned char *out, unsigned long *outlen, prng_state *prng)
+{
+   LTC_ARGCHK(out    != NULL);
+   LTC_ARGCHK(outlen != NULL);
+   LTC_ARGCHK(prng   != NULL);
+
+   /* we'll write 64 bytes for s&g's */
+   if (*outlen < 64) {
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+
+   if (yarrow_read(out, 64, prng) != 64) {
+      return CRYPT_ERROR_READPRNG;
+   }
+   *outlen = 64;
+
+   return CRYPT_OK;
+}
+ 
+/**
+  Import a PRNG state
+  @param in       The PRNG state
+  @param inlen    Size of the state
+  @param prng     The PRNG to import
+  @return CRYPT_OK if successful
+*/  
+int yarrow_import(const unsigned char *in, unsigned long inlen, prng_state *prng)
+{
+   int err;
+
+   LTC_ARGCHK(in   != NULL);
+   LTC_ARGCHK(prng != NULL);
+
+   if (inlen != 64) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   if ((err = yarrow_start(prng)) != CRYPT_OK) {
+      return err;
+   }
+   return yarrow_add_entropy(in, 64, prng);
+}
+
+/**
+  PRNG self-test
+  @return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled
+*/  
+int yarrow_test(void)
+{
+#ifndef LTC_TEST
+   return CRYPT_NOP;
+#else
+   int err;
+   prng_state prng;
+
+   if ((err = yarrow_start(&prng)) != CRYPT_OK) {
+      return err;
+   }
+   
+   /* now let's test the hash/cipher that was chosen */
+   if ((err = cipher_descriptor[prng.yarrow.cipher].test()) != CRYPT_OK) {
+      return err; 
+   }
+   if ((err = hash_descriptor[prng.yarrow.hash].test()) != CRYPT_OK) {
+      return err; 
+   }
+
+   yarrow_done(&prng);
+   return CRYPT_OK;
+#endif
+}
+
+#endif
+
+
+/* $Source: /cvs/libtom/libtomcrypt/src/prngs/yarrow.c,v $ */
+/* $Revision: 1.5 $ */
+/* $Date: 2005/05/05 14:35:59 $ */