Initial import.

src/symcipher/aes_ct_ctr.c

@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+/* see bearssl_block.h */
+void
+br_aes_ct_ctr_init(br_aes_ct_ctr_keys *ctx,
+	const void *key, size_t len)
+{
+	ctx->vtable = &br_aes_ct_ctr_vtable;
+	ctx->num_rounds = br_aes_ct_keysched(ctx->skey, key, len);
+}
+
+static void
+xorbuf(void *dst, const void *src, size_t len)
+{
+	unsigned char *d;
+	const unsigned char *s;
+
+	d = dst;
+	s = src;
+	while (len -- > 0) {
+		*d ++ ^= *s ++;
+	}
+}
+
+/* see bearssl_block.h */
+uint32_t
+br_aes_ct_ctr_run(const br_aes_ct_ctr_keys *ctx,
+	const void *iv, uint32_t cc, void *data, size_t len)
+{
+	unsigned char *buf;
+	const unsigned char *ivbuf;
+	uint32_t iv0, iv1, iv2;
+	uint32_t sk_exp[120];
+
+	br_aes_ct_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
+	ivbuf = iv;
+	iv0 = br_dec32le(ivbuf);
+	iv1 = br_dec32le(ivbuf + 4);
+	iv2 = br_dec32le(ivbuf + 8);
+	buf = data;
+	while (len > 0) {
+		uint32_t q[8];
+		unsigned char tmp[32];
+
+		/*
+		 * TODO: see if we can save on the first br_aes_ct_ortho()
+		 * call, since iv0/iv1/iv2 are constant for the whole run.
+		 */
+		q[0] = q[1] = iv0;
+		q[2] = q[3] = iv1;
+		q[4] = q[5] = iv2;
+		q[6] = br_swap32(cc);
+		q[7] = br_swap32(cc + 1);
+		br_aes_ct_ortho(q);
+		br_aes_ct_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
+		br_aes_ct_ortho(q);
+		br_enc32le(tmp, q[0]);
+		br_enc32le(tmp + 4, q[2]);
+		br_enc32le(tmp + 8, q[4]);
+		br_enc32le(tmp + 12, q[6]);
+		br_enc32le(tmp + 16, q[1]);
+		br_enc32le(tmp + 20, q[3]);
+		br_enc32le(tmp + 24, q[5]);
+		br_enc32le(tmp + 28, q[7]);
+
+		if (len <= 32) {
+			xorbuf(buf, tmp, len);
+			cc ++;
+			if (len > 16) {
+				cc ++;
+			}
+			break;
+		}
+		xorbuf(buf, tmp, 32);
+		buf += 32;
+		len -= 32;
+		cc += 2;
+	}
+	return cc;
+}
+
+/* see bearssl_block.h */
+const br_block_ctr_class br_aes_ct_ctr_vtable = {
+	sizeof(br_aes_ct_ctr_keys),
+	16,
+	4,
+	(void (*)(const br_block_ctr_class **, const void *, size_t))
+		&br_aes_ct_ctr_init,
+	(uint32_t (*)(const br_block_ctr_class *const *,
+		const void *, uint32_t, void *, size_t))
+		&br_aes_ct_ctr_run
+};