--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/modes/ofb/ofb_encrypt.c	Sun May 08 06:36:47 2005 +0000
@@ -0,0 +1,54 @@
+/* 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 ofb_encrypt.c
+  OFB implementation, encrypt data, Tom St Denis
+*/
+
+#ifdef OFB
+
+/**
+  OFB encrypt
+  @param pt     Plaintext
+  @param ct     [out] Ciphertext
+  @param len    Length of plaintext (octets)
+  @param ofb    OFB state
+  @return CRYPT_OK if successful
+*/
+int ofb_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_OFB *ofb)
+{
+   int err;
+   LTC_ARGCHK(pt != NULL);
+   LTC_ARGCHK(ct != NULL);
+   LTC_ARGCHK(ofb != NULL);
+   if ((err = cipher_is_valid(ofb->cipher)) != CRYPT_OK) {
+       return err;
+   }
+   
+   /* is blocklen/padlen valid? */
+   if (ofb->blocklen < 0 || ofb->blocklen > (int)sizeof(ofb->IV) ||
+       ofb->padlen   < 0 || ofb->padlen   > (int)sizeof(ofb->IV)) {
+      return CRYPT_INVALID_ARG;
+   }
+   
+   while (len-- > 0) {
+       if (ofb->padlen == ofb->blocklen) {
+          cipher_descriptor[ofb->cipher].ecb_encrypt(ofb->IV, ofb->IV, &ofb->key);
+          ofb->padlen = 0;
+       }
+       *ct++ = *pt++ ^ ofb->IV[ofb->padlen++];
+   }
+   return CRYPT_OK;
+}
+
+#endif