From c631998044731bfa576cc5cee9d45ab17b808bbf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Fri, 30 Jan 2015 14:37:59 +0100
Subject: [PATCH] New function chacha_set_nonce96.
---
ChangeLog | 6 ++++++
chacha-set-nonce.c | 9 +++++++++
chacha.h | 5 +++++
testsuite/chacha-test.c | 27 ++++++++++++++++++++++++---
4 files changed, 44 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 00007fe0..01ee1559 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-01-30 Niels Möller <nisse@lysator.liu.se>
+
+ * chacha-set-nonce.c (chacha_set_nonce96): New function.
+ * chacha.h (CHACHA_NONCE96_SIZE): New constant.
+ * testsuite/chacha-test.c: Add test for chacha with 96-bit nonce.
+
2015-01-27 Niels Möller <nisse@lysator.liu.se>
* ecc.h: Deleted declarations of unused itch functions. Moved
diff --git a/chacha-set-nonce.c b/chacha-set-nonce.c
index e73babce..607f176b 100644
--- a/chacha-set-nonce.c
+++ b/chacha-set-nonce.c
@@ -59,3 +59,12 @@ chacha_set_nonce(struct chacha_ctx *ctx, const uint8_t *nonce)
ctx->state[14] = LE_READ_UINT32(nonce + 0);
ctx->state[15] = LE_READ_UINT32(nonce + 4);
}
+
+void
+chacha_set_nonce96(struct chacha_ctx *ctx, const uint8_t *nonce)
+{
+ ctx->state[12] = 0;
+ ctx->state[13] = LE_READ_UINT32(nonce + 0);
+ ctx->state[14] = LE_READ_UINT32(nonce + 4);
+ ctx->state[15] = LE_READ_UINT32(nonce + 8);
+}
diff --git a/chacha.h b/chacha.h
index 41df7076..3f082834 100644
--- a/chacha.h
+++ b/chacha.h
@@ -45,6 +45,7 @@ extern "C" {
/* Name mangling */
#define chacha_set_key nettle_chacha_set_key
#define chacha_set_nonce nettle_chacha_set_nonce
+#define chacha_set_nonce96 nettle_chacha_set_nonce96
#define chacha_crypt nettle_chacha_crypt
#define _chacha_core _nettle_chacha_core
@@ -52,6 +53,7 @@ extern "C" {
#define CHACHA_KEY_SIZE 32
#define CHACHA_BLOCK_SIZE 64
#define CHACHA_NONCE_SIZE 8
+#define CHACHA_NONCE96_SIZE 12
#define _CHACHA_STATE_LENGTH 16
@@ -77,6 +79,9 @@ chacha_set_key(struct chacha_ctx *ctx, const uint8_t *key);
void
chacha_set_nonce(struct chacha_ctx *ctx, const uint8_t *nonce);
+void
+chacha_set_nonce96(struct chacha_ctx *ctx, const uint8_t *nonce);
+
void
chacha_crypt(struct chacha_ctx *ctx, size_t length,
uint8_t *dst, const uint8_t *src);
diff --git a/testsuite/chacha-test.c b/testsuite/chacha-test.c
index 8c5630da..9edb9410 100644
--- a/testsuite/chacha-test.c
+++ b/testsuite/chacha-test.c
@@ -44,20 +44,30 @@ test_chacha(const struct tstring *key, const struct tstring *nonce,
ASSERT (key->length == CHACHA_KEY_SIZE);
chacha_set_key (&ctx, key->data);
- ASSERT (nonce->length == CHACHA_NONCE_SIZE);
if (rounds == 20)
{
uint8_t *data = xalloc (expected->length + 2);
- data++;
size_t length;
+ data++;
for (length = 1; length <= expected->length; length++)
{
data[-1] = 17;
memset (data, 0, length);
data[length] = 17;
- chacha_set_nonce(&ctx, nonce->data);
+ if (nonce->length == CHACHA_NONCE_SIZE)
+ chacha_set_nonce(&ctx, nonce->data);
+ else if (nonce->length == CHACHA_NONCE96_SIZE)
+ {
+ chacha_set_nonce96(&ctx, nonce->data);
+ /* Use initial counter 1, for
+ draft-irtf-cfrg-chacha20-poly1305-08 test cases. */
+ ctx.state[12]++;
+ }
+ else
+ die ("Bad nonce size %u.\n", (unsigned) nonce->length);
+
chacha_crypt (&ctx, length, data, data);
ASSERT (data[-1] == 17);
@@ -84,6 +94,7 @@ test_chacha(const struct tstring *key, const struct tstring *nonce,
numbers of rounds. */
uint32_t out[_CHACHA_STATE_LENGTH];
ASSERT (expected->length == CHACHA_BLOCK_SIZE);
+ ASSERT (nonce->length == CHACHA_NONCE_SIZE);
chacha_set_nonce(&ctx, nonce->data);
_chacha_core (out, ctx.state, rounds);
@@ -622,4 +633,14 @@ test_main(void)
"ae2c4c90225ba9ea 14d518f55929dea0"
"98ca7a6ccfe61227 053c84e49a4a3332"),
20);
+
+ /* From draft-irtf-cfrg-chacha20-poly1305-08, with 96-bit nonce */
+ test_chacha(SHEX("0001020304050607 08090a0b0c0d0e0f"
+ "1011121314151617 18191a1b1c1d1e1f"),
+ SHEX("000000090000004a 00000000"),
+ SHEX("10f1e7e4d13b5915 500fdd1fa32071c4"
+ "c7d1f4c733c06803 0422aa9ac3d46c4e"
+ "d2826446079faa09 14c2d705d98b02a2"
+ "b5129cd1de164eb9 cbd083e8a2503c4e"),
+ 20);
}
--
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