This series provides a functional SHA-256 implementation and wires it
up, along with some housekeeping patches to make it suitable for
testing.
Changes from v4:
* Downcase hex constants for consistency.
* Remove needless parentheses in return statement.
* Remove braces for single statement loops.
* Switch to +=.
* Add references to rationale for SHA-256.
* Remove inclusion of "git-compat-util.h" in header.
Changes from v3:
* Switch to using inline functions instead of macros in many cases.
* Undefine remaining macros at the top.
Changes from v2:
* Improve commit messages to include timing and performance information.
* Improve commit messages to be less ambiguous and more friendly to a
wider variety of English speakers.
* Prefer functions taking struct git_hash_algo in hex.c.
* Port pieces of the block-sha1 implementation over to the block-sha256
implementation for better compatibility.
* Drop patch 13 in favor of further discussion about the best way
forward for versioning commit graph.
* Rename the test so as to have a different number from other tests.
* Rebase on master.
Changes from v1:
* Add a hash_to_hex function mirroring sha1_to_hex, but for
the_hash_algo.
* Strip commit message explanation about why we chose SHA-256.
* Rebase on master
* Strip leading whitespace from commit message.
* Improve commit-graph patch to cover new code added since v1.
* Be more honest about the scope of work involved in porting the SHA-256
implementation out of libtomcrypt.
* Revert change to limit hashcmp to 20 bytes.
brian m. carlson (12):
sha1-file: rename algorithm to "sha1"
sha1-file: provide functions to look up hash algorithms
hex: introduce functions to print arbitrary hashes
cache: make hashcmp and hasheq work with larger hashes
t: add basic tests for our SHA-1 implementation
t: make the sha1 test-tool helper generic
sha1-file: add a constant for hash block size
t/helper: add a test helper to compute hash speed
commit-graph: convert to using the_hash_algo
Add a base implementation of SHA-256 support
sha256: add an SHA-256 implementation using libgcrypt
hash: add an SHA-256 implementation using OpenSSL
Makefile | 22 +++
cache.h | 51 ++++---
commit-graph.c | 33 ++---
hash.h | 41 +++++-
hex.c | 32 +++--
sha1-file.c | 70 ++++++++-
sha256/block/sha256.c | 196 ++++++++++++++++++++++++++
sha256/block/sha256.h | 26 ++++
sha256/gcrypt.h | 30 ++++
t/helper/test-hash-speed.c | 61 ++++++++
t/helper/{test-sha1.c => test-hash.c} | 19 +--
t/helper/test-sha1.c | 52 +------
t/helper/test-sha256.c | 7 +
t/helper/test-tool.c | 2 +
t/helper/test-tool.h | 4 +
t/t0015-hash.sh | 54 +++++++
16 files changed, 596 insertions(+), 104 deletions(-)
create mode 100644 sha256/block/sha256.c
create mode 100644 sha256/block/sha256.h
create mode 100644 sha256/gcrypt.h
create mode 100644 t/helper/test-hash-speed.c
copy t/helper/{test-sha1.c => test-hash.c} (65%)
create mode 100644 t/helper/test-sha256.c
create mode 100755 t/t0015-hash.sh
Range-diff against v4:
1: a004a4c982 < -: ---------- :hash-impl
2: cf9f7f5620 = 1: cf9f7f5620 sha1-file: rename algorithm to "sha1"
3: 0144deaebe = 2: 0144deaebe sha1-file: provide functions to look up hash algorithms
4: b74858fb03 = 3: b74858fb03 hex: introduce functions to print arbitrary hashes
5: e9703017a4 = 4: e9703017a4 cache: make hashcmp and hasheq work with larger hashes
6: ab85a834fd = 5: ab85a834fd t: add basic tests for our SHA-1 implementation
7: 962f6d8903 = 6: 962f6d8903 t: make the sha1 test-tool helper generic
8: 53addf4d58 = 7: 53addf4d58 sha1-file: add a constant for hash block size
9: 9ace10faa2 = 8: 9ace10faa2 t/helper: add a test helper to compute hash speed
10: 9adc56d01e = 9: 9adc56d01e commit-graph: convert to using the_hash_algo
11: f48cb1ad27 ! 10: 90544c504c Add a base implementation of SHA-256 support
@@ -4,7 +4,9 @@
SHA-1 is weak and we need to transition to a new hash function. For
some time, we have referred to this new function as NewHash. Recently,
- we decided to pick SHA-256 as NewHash.
+ we decided to pick SHA-256 as NewHash. The reasons behind the choice of
+ SHA-256 are outlined in the thread starting at [1] and in the commit
+ history for the hash function transition document.
Add a basic implementation of SHA-256 based off libtomcrypt, which is in
the public domain. Optimize it and restructure it to meet our coding
@@ -20,6 +22,8 @@
SHA-256 in Git. Additional patches are needed to prepare the code to
handle a larger hash algorithm and further test fixes are needed.
+ [1] https://public-inbox.org/git/20180609224913.GC38834@xxxxxxxxxxxxxxxxxxxxxxxxxx/
+
Signed-off-by: brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx>
diff --git a/Makefile b/Makefile
@@ -216,14 +220,14 @@
+{
+ ctx->offset = 0;
+ ctx->size = 0;
-+ ctx->state[0] = 0x6A09E667UL;
-+ ctx->state[1] = 0xBB67AE85UL;
-+ ctx->state[2] = 0x3C6EF372UL;
-+ ctx->state[3] = 0xA54FF53AUL;
-+ ctx->state[4] = 0x510E527FUL;
-+ ctx->state[5] = 0x9B05688CUL;
-+ ctx->state[6] = 0x1F83D9ABUL;
-+ ctx->state[7] = 0x5BE0CD19UL;
++ ctx->state[0] = 0x6a09e667ul;
++ ctx->state[1] = 0xbb67ae85ul;
++ ctx->state[2] = 0x3c6ef372ul;
++ ctx->state[3] = 0xa54ff53aul;
++ ctx->state[4] = 0x510e527ful;
++ ctx->state[5] = 0x9b05688cul;
++ ctx->state[6] = 0x1f83d9abul;
++ ctx->state[7] = 0x5be0cd19ul;
+}
+
+static inline uint32_t ror(uint32_t x, unsigned n)
@@ -233,12 +237,12 @@
+
+static inline uint32_t ch(uint32_t x, uint32_t y, uint32_t z)
+{
-+ return (z ^ (x & (y ^ z)));
++ return z ^ (x & (y ^ z));
+}
+
+static inline uint32_t maj(uint32_t x, uint32_t y, uint32_t z)
+{
-+ return (((x | y) & z) | (x & y));
++ return ((x | y) & z) | (x & y);
+}
+
+static inline uint32_t sigma0(uint32_t x)
@@ -268,19 +272,16 @@
+ int i;
+
+ /* copy state into S */
-+ for (i = 0; i < 8; i++) {
++ for (i = 0; i < 8; i++)
+ S[i] = ctx->state[i];
-+ }
+
+ /* copy the state into 512-bits into W[0..15] */
-+ for (i = 0; i < 16; i++, buf += sizeof(uint32_t)) {
++ for (i = 0; i < 16; i++, buf += sizeof(uint32_t))
+ W[i] = get_be32(buf);
-+ }
+
+ /* fill W[16..63] */
-+ for (i = 16; i < 64; i++) {
++ for (i = 16; i < 64; i++)
+ W[i] = gamma1(W[i - 2]) + W[i - 7] + gamma0(W[i - 15]) + W[i - 16];
-+ }
+
+#define RND(a,b,c,d,e,f,g,h,i,ki) \
+ t0 = h + sigma1(e) + ch(e, f, g) + ki + W[i]; \
@@ -353,10 +354,8 @@
+ RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],62,0xbef9a3f7);
+ RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],63,0xc67178f2);
+
-+
-+ for (i = 0; i < 8; i++) {
-+ ctx->state[i] = ctx->state[i] + S[i];
-+ }
++ for (i = 0; i < 8; i++)
++ ctx->state[i] += S[i];
+}
+
+void blk_SHA256_Update(blk_SHA256_CTX *ctx, const void *data, size_t len)
12: fe8f2ba01c = 11: 467c86e878 sha256: add an SHA-256 implementation using libgcrypt
13: 38142d8fc6 = 12: 73e4bc17d0 hash: add an SHA-256 implementation using OpenSSL
