--- /dev/null
+/* 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_process.c
+ LRW_MODE implementation, Encrypt/decrypt blocks, Tom St Denis
+*/
+
+#ifdef LTC_LRW_MODE
+
+/**
+ Process blocks with LRW, since decrypt/encrypt are largely the same they share this code.
+ @param pt The "input" data
+ @param ct [out] The "output" data
+ @param len The length of the input, must be a multiple of 128-bits (16 octets)
+ @param mode LRW_ENCRYPT or LRW_DECRYPT
+ @param lrw The LRW state
+ @return CRYPT_OK if successful
+*/
+int lrw_process(const unsigned char *pt, unsigned char *ct, unsigned long len, int mode, symmetric_LRW *lrw)
+{
+ unsigned char prod[16];
+ int x, err;
+#ifdef LTC_LRW_TABLES
+ int y;
+#endif
+
+ LTC_ARGCHK(pt != NULL);
+ LTC_ARGCHK(ct != NULL);
+ LTC_ARGCHK(lrw != NULL);
+
+ if (len & 15) {
+ return CRYPT_INVALID_ARG;
+ }
+
+ while (len) {
+ /* copy pad */
+ XMEMCPY(prod, lrw->pad, 16);
+
+ /* increment IV */
+ for (x = 15; x >= 0; x--) {
+ lrw->IV[x] = (lrw->IV[x] + 1) & 255;
+ if (lrw->IV[x]) {
+ break;
+ }
+ }
+
+ /* update pad */
+#ifdef LTC_LRW_TABLES
+ /* for each byte changed we undo it's affect on the pad then add the new product */
+ for (; x < 16; x++) {
+#ifdef LTC_FAST
+ for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
+ *(LTC_FAST_TYPE_PTR_CAST(lrw->pad + y)) ^= *(LTC_FAST_TYPE_PTR_CAST(&lrw->PC[x][lrw->IV[x]][y])) ^ *(LTC_FAST_TYPE_PTR_CAST(&lrw->PC[x][(lrw->IV[x]-1)&255][y]));
+ }
+#else
+ for (y = 0; y < 16; y++) {
+ lrw->pad[y] ^= lrw->PC[x][lrw->IV[x]][y] ^ lrw->PC[x][(lrw->IV[x]-1)&255][y];
+ }
+#endif
+ }
+#else
+ gcm_gf_mult(lrw->tweak, lrw->IV, lrw->pad);
+#endif
+
+ /* xor prod */
+#ifdef LTC_FAST
+ for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) {
+ *(LTC_FAST_TYPE_PTR_CAST(ct + x)) = *(LTC_FAST_TYPE_PTR_CAST(pt + x)) ^ *(LTC_FAST_TYPE_PTR_CAST(prod + x));
+ }
+#else
+ for (x = 0; x < 16; x++) {
+ ct[x] = pt[x] ^ prod[x];
+ }
+#endif
+
+ /* send through cipher */
+ if (mode == LRW_ENCRYPT) {
+ if ((err = cipher_descriptor[lrw->cipher].ecb_encrypt(ct, ct, &lrw->key)) != CRYPT_OK) {
+ return err;
+ }
+ } else {
+ if ((err = cipher_descriptor[lrw->cipher].ecb_decrypt(ct, ct, &lrw->key)) != CRYPT_OK) {
+ return err;
+ }
+ }
+
+ /* xor prod */
+#ifdef LTC_FAST
+ for (x = 0; x < 16; x += sizeof(LTC_FAST_TYPE)) {
+ *(LTC_FAST_TYPE_PTR_CAST(ct + x)) = *(LTC_FAST_TYPE_PTR_CAST(ct + x)) ^ *(LTC_FAST_TYPE_PTR_CAST(prod + x));
+ }
+#else
+ for (x = 0; x < 16; x++) {
+ ct[x] = ct[x] ^ prod[x];
+ }
+#endif
+
+ /* move to next */
+ pt += 16;
+ ct += 16;
+ len -= 16;
+ }
+
+ return CRYPT_OK;
+}
+
+#endif
+/* ref: $Format:%D$ */
+/* git commit: $Format:%H$ */
+/* commit time: $Format:%ai$ */