Re: SHA1 collisions found

Junio C Hamano [off-list ref] writes:

quoted

  [1/3]: add collision-detecting sha1 implementation
  [2/3]: sha1dc: adjust header includes for git
  [3/3]: Makefile: add USE_SHA1DC knob

I was lazy so I fetched the above and then added this on top before
I start to play with it.

-- >8 --
From: Junio C Hamano <redacted>
Date: Tue, 28 Feb 2017 10:39:25 -0800
Subject: [PATCH] sha1dc: resurrect LICENSE file

In a way similar to 8415558f55 ("sha1dc: avoid c99
declaration-after-statement", 2017-02-24), we would want this on
top.

-- >8 --
Subject: sha1dc: avoid 'for' loop initial decl

We write this:

	type i;
	for (i = initial; i < limit; i++)

instead of this:

	for (type i = initial; i < limit; i++)

the latter of which is from c99.

Signed-off-by: Junio C Hamano <redacted>
---
 sha1dc/sha1.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sha1dc/sha1.c b/sha1dc/sha1.c
index f4e261ae7a..6569b403e9 100644
--- a/sha1dc/sha1.c
+++ b/sha1dc/sha1.c

@@ -41,7 +41,8 @@
 
 void sha1_message_expansion(uint32_t W[80])
 {
-	for (unsigned i = 16; i < 80; ++i)
+	unsigned i;
+	for (i = 16; i < 80; ++i)
 		W[i] = rotate_left(W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16], 1);
 }
 

@@ -49,9 +50,10 @@ void sha1_compression(uint32_t ihv[5], const uint32_t m[16])
 {
 	uint32_t W[80];
 	uint32_t a, b, c, d, e;
+	unsigned i;
 
 	memcpy(W, m, 16 * 4);
-	for (unsigned i = 16; i < 80; ++i)
+	for (i = 16; i < 80; ++i)
 		W[i] = rotate_left(W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16], 1);
 
 	a = ihv[0];