diff src/modes/ecb/ecb_decrypt.c @ 191:1c15b283127b libtomcrypt-orig

Import of libtomcrypt 1.02 with manual path rename rearrangement etc
author Matt Johnston <matt@ucc.asn.au>
date Fri, 06 May 2005 13:23:02 +0000
parents
children 39d5d58461d6
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/modes/ecb/ecb_decrypt.c	Fri May 06 13:23:02 2005 +0000
@@ -0,0 +1,55 @@
+/* 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 ecb_decrypt.c
+  ECB implementation, decrypt a block, Tom St Denis
+*/
+
+#ifdef ECB
+
+/**
+  ECB decrypt
+  @param ct     Ciphertext
+  @param pt     [out] Plaintext
+  @param len    The number of octets to process (must be multiple of the cipher block size)
+  @param ecb    ECB state
+  @return CRYPT_OK if successful
+*/
+int ecb_decrypt(const unsigned char *ct, unsigned char *pt, unsigned long len, symmetric_ECB *ecb)
+{
+   int err;
+   LTC_ARGCHK(pt != NULL);
+   LTC_ARGCHK(ct != NULL);
+   LTC_ARGCHK(ecb != NULL);
+   if ((err = cipher_is_valid(ecb->cipher)) != CRYPT_OK) {
+       return err;
+   }
+   if (len % cipher_descriptor[ecb->cipher].block_length) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* check for accel */
+   if (cipher_descriptor[ecb->cipher].accel_ecb_decrypt != NULL) {
+      cipher_descriptor[ecb->cipher].accel_ecb_decrypt(ct, pt, len / cipher_descriptor[ecb->cipher].block_length, &ecb->key);
+   } else {
+      while (len) {
+         cipher_descriptor[ecb->cipher].ecb_decrypt(ct, pt, &ecb->key);
+         pt  += cipher_descriptor[ecb->cipher].block_length;
+         ct  += cipher_descriptor[ecb->cipher].block_length;
+         len -= cipher_descriptor[ecb->cipher].block_length;
+      }
+   }
+   return CRYPT_OK;
+}
+
+#endif