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thirdparty/libtomcrypt/modes/lrw/lrw_setiv.c

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+/* 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.
+ */
+#include "tomcrypt.h"
+
+/**
+   @file lrw_setiv.c
+   LRW_MODE implementation, Set the current IV, Tom St Denis
+*/
+
+#ifdef LTC_LRW_MODE
+
+/**
+  Set the IV for LRW
+  @param IV      The IV, must be 16 octets
+  @param len     Length ... must be 16 :-)
+  @param lrw     The LRW state to update
+  @return CRYPT_OK if successful
+*/
+int lrw_setiv(const unsigned char *IV, unsigned long len, symmetric_LRW *lrw)
+{
+   int           err;
+#ifdef LTC_LRW_TABLES
+   unsigned char T[16];
+   int           x, y;
+#endif
+   LTC_ARGCHK(IV != NULL);
+   LTC_ARGCHK(lrw != NULL);
+
+   if (len != 16) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   if ((err = cipher_is_valid(lrw->cipher)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* copy the IV */
+   XMEMCPY(lrw->IV, IV, 16);
+
+   /* check if we have to actually do work */
+   if (cipher_descriptor[lrw->cipher].accel_lrw_encrypt != NULL && cipher_descriptor[lrw->cipher].accel_lrw_decrypt != NULL) {
+       /* we have accelerators, let's bail since they don't use lrw->pad anyways */
+       return CRYPT_OK;
+   }
+
+#ifdef LTC_LRW_TABLES
+   XMEMCPY(T, &lrw->PC[0][IV[0]][0], 16);
+   for (x = 1; x < 16; x++) {
+#ifdef LTC_FAST
+       for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
+           *(LTC_FAST_TYPE_PTR_CAST(T + y)) ^= *(LTC_FAST_TYPE_PTR_CAST(&lrw->PC[x][IV[x]][y]));
+       }
+#else
+       for (y = 0; y < 16; y++) {
+           T[y] ^= lrw->PC[x][IV[x]][y];
+       }
+#endif
+   }
+   XMEMCPY(lrw->pad, T, 16);
+#else
+   gcm_gf_mult(lrw->tweak, IV, lrw->pad);
+#endif
+
+   return CRYPT_OK;
+}
+
+
+#endif
+/* ref:         HEAD -> master, tag: v1.18.2 */
+/* git commit:  7e7eb695d581782f04b24dc444cbfde86af59853 */
+/* commit time: 2018-07-01 22:49:01 +0200 */