初始版本

external/cifra_AES128-EAX/modes.c

@@ -0,0 +1,99 @@
+/*
+ * cifra - embedded cryptography library
+ * Written in 2014 by Joseph Birr-Pixton <jpixton@gmail.com>
+ *
+ * To the extent possible under law, the author(s) have dedicated all
+ * copyright and related and neighboring rights to this software to the
+ * public domain worldwide. This software is distributed without any
+ * warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication
+ * along with this software. If not, see
+ * <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+#include "prp.h"
+#include "modes.h"
+#include "bitops.h"
+#include "blockwise.h"
+
+#include <string.h>
+#include "tassert.h"
+
+/* CBC */
+void cf_cbc_init(cf_cbc *ctx, const cf_prp *prp, void *prpctx, const uint8_t iv[CF_MAXBLOCK])
+{
+  ctx->prp = prp;
+  ctx->prpctx = prpctx;
+  memcpy(ctx->block, iv, prp->blocksz);
+}
+
+void cf_cbc_encrypt(cf_cbc *ctx, const uint8_t *input, uint8_t *output, size_t blocks)
+{
+  uint8_t buf[CF_MAXBLOCK];
+  size_t nblk = ctx->prp->blocksz;
+
+  while (blocks--)
+  {
+    xor_bb(buf, input, ctx->block, nblk);
+    ctx->prp->encrypt(ctx->prpctx, buf, ctx->block);
+    memcpy(output, ctx->block, nblk);
+    input += nblk;
+    output += nblk;
+  }
+}
+
+void cf_cbc_decrypt(cf_cbc *ctx, const uint8_t *input, uint8_t *output, size_t blocks)
+{
+  uint8_t buf[CF_MAXBLOCK];
+  size_t nblk = ctx->prp->blocksz;
+
+  while (blocks--)
+  {
+    ctx->prp->decrypt(ctx->prpctx, input, buf);
+    xor_bb(output, buf, ctx->block, nblk);
+    memcpy(ctx->block, input, nblk);
+    input += nblk;
+    output += nblk;
+  }
+}
+
+/* CTR */
+void cf_ctr_init(cf_ctr *ctx, const cf_prp *prp, void *prpctx, const uint8_t nonce[CF_MAXBLOCK])
+{
+  memset(ctx, 0, sizeof *ctx);
+  ctx->counter_offset = 0;
+  ctx->counter_width = prp->blocksz;
+  ctx->prp = prp;
+  ctx->prpctx = prpctx;
+  ctx->nkeymat = 0;
+  memcpy(ctx->nonce, nonce, prp->blocksz);
+}
+
+void cf_ctr_custom_counter(cf_ctr *ctx, size_t offset, size_t width)
+{
+  assert(ctx->prp->blocksz <= offset + width);
+  ctx->counter_offset = offset;
+  ctx->counter_width = width;
+}
+
+static void ctr_next_block(void *vctx, uint8_t *out)
+{
+  cf_ctr *ctx = vctx;
+  ctx->prp->encrypt(ctx->prpctx, ctx->nonce, out);
+  incr_be(ctx->nonce + ctx->counter_offset, ctx->counter_width);
+}
+
+void cf_ctr_cipher(cf_ctr *ctx, const uint8_t *input, uint8_t *output, size_t bytes)
+{
+  cf_blockwise_xor(ctx->keymat, &ctx->nkeymat,
+                   ctx->prp->blocksz,
+                   input, output, bytes,
+                   ctr_next_block,
+                   ctx);
+}
+
+void cf_ctr_discard_block(cf_ctr *ctx)
+{
+  ctx->nkeymat = 0;
+}