+ word32 iv[4], b[4], tmp;
+ int i;
+
+ assert((len & 15) == 0);
+
+ memcpy(iv, ctx->iv, sizeof(iv));
+
+ while (len > 0) {
+ memcpy(b, iv, sizeof(b));
+ aes_encrypt(ctx, b);
+ for (i = 0; i < 4; i++) {
+ tmp = GET_32BIT_MSB_FIRST(blk + 4 * i);
+ PUT_32BIT_MSB_FIRST(blk + 4 * i, tmp ^ b[i]);
+ }
+ for (i = 3; i >= 0; i--)
+ if ((iv[i] = (iv[i] + 1) & 0xffffffff) != 0)
+ break;
+ blk += 16;
+ len -= 16;
+ }
+
+ memcpy(ctx->iv, iv, sizeof(iv));