diff --git a/arm/sha1.c b/arm/sha1.c
index 9e3ae038e8..c61ad4aff9 100644
--- a/arm/sha1.c
+++ b/arm/sha1.c
@@ -8,9 +8,9 @@
 #include <string.h>
 #include "sha1.h"
 
-extern void sha_transform(uint32_t *hash, const unsigned char *data, uint32_t *W);
+extern void arm_sha_transform(uint32_t *hash, const unsigned char *data, uint32_t *W);
 
-void SHA1_Init(SHA_CTX *c)
+void arm_SHA1_Init(arm_SHA_CTX *c)
 {
 	c->len = 0;
 	c->hash[0] = 0x67452301;
@@ -20,7 +20,7 @@ void SHA1_Init(SHA_CTX *c)
 	c->hash[4] = 0xc3d2e1f0;
 }
 
-void SHA1_Update(SHA_CTX *c, const void *p, unsigned long n)
+void arm_SHA1_Update(arm_SHA_CTX *c, const void *p, unsigned long n)
 {
 	uint32_t workspace[80];
 	unsigned int partial;
@@ -32,12 +32,12 @@ void SHA1_Update(SHA_CTX *c, const void *p, unsigned long n)
 		if (partial) {
 			done = 64 - partial;
 			memcpy(c->buffer + partial, p, done);
-			sha_transform(c->hash, c->buffer, workspace);
+			arm_sha_transform(c->hash, c->buffer, workspace);
 			partial = 0;
 		} else
 			done = 0;
 		while (n >= done + 64) {
-			sha_transform(c->hash, p + done, workspace);
+			arm_sha_transform(c->hash, p + done, workspace);
 			done += 64;
 		}
 	} else
@@ -46,7 +46,7 @@ void SHA1_Update(SHA_CTX *c, const void *p, unsigned long n)
 		memcpy(c->buffer + partial, p + done, n - done);
 }
 
-void SHA1_Final(unsigned char *hash, SHA_CTX *c)
+void arm_SHA1_Final(unsigned char *hash, arm_SHA_CTX *c)
 {
 	uint64_t bitlen;
 	uint32_t bitlen_hi, bitlen_lo;
@@ -57,7 +57,7 @@ void SHA1_Final(unsigned char *hash, SHA_CTX *c)
 	bitlen = c->len << 3;
 	offset = c->len & 0x3f;
 	padlen = ((offset < 56) ? 56 : (64 + 56)) - offset;
-	SHA1_Update(c, padding, padlen);
+	arm_SHA1_Update(c, padding, padlen);
 
 	bitlen_hi = bitlen >> 32;
 	bitlen_lo = bitlen & 0xffffffff;
@@ -69,7 +69,7 @@ void SHA1_Final(unsigned char *hash, SHA_CTX *c)
 	bits[5] = bitlen_lo >> 16;
 	bits[6] = bitlen_lo >> 8;
 	bits[7] = bitlen_lo;
-	SHA1_Update(c, bits, 8);
+	arm_SHA1_Update(c, bits, 8);
 
 	for (i = 0; i < 5; i++) {
 		uint32_t v = c->hash[i];
diff --git a/arm/sha1.h b/arm/sha1.h
index 3952646349..b61b618486 100644
--- a/arm/sha1.h
+++ b/arm/sha1.h
@@ -7,12 +7,17 @@
 
 #include <stdint.h>
 
-typedef struct sha_context {
+typedef struct {
 	uint64_t len;
 	uint32_t hash[5];
 	unsigned char buffer[64];
-} SHA_CTX;
+} arm_SHA_CTX;
 
-void SHA1_Init(SHA_CTX *c);
-void SHA1_Update(SHA_CTX *c, const void *p, unsigned long n);
-void SHA1_Final(unsigned char *hash, SHA_CTX *c);
+void arm_SHA1_Init(arm_SHA_CTX *c);
+void arm_SHA1_Update(arm_SHA_CTX *c, const void *p, unsigned long n);
+void arm_SHA1_Final(unsigned char *hash, arm_SHA_CTX *c);
+
+#define git_SHA_CTX	arm_SHA_CTX
+#define git_SHA1_Init	arm_SHA1_Init
+#define git_SHA1_Update	arm_SHA1_Update
+#define git_SHA1_Final	arm_SHA1_Final
diff --git a/arm/sha1_arm.S b/arm/sha1_arm.S
index 8c1cb99fb4..41e92636e0 100644
--- a/arm/sha1_arm.S
+++ b/arm/sha1_arm.S
@@ -10,7 +10,7 @@
  */
 
 	.text
-	.globl	sha_transform
+	.globl	arm_sha_transform
 
 /*
  * void sha_transform(uint32_t *hash, const unsigned char *data, uint32_t *W);
@@ -18,7 +18,7 @@
  * note: the "data" pointer may be unaligned.
  */
 
-sha_transform:
+arm_sha_transform:
 
 	stmfd	sp!, {r4 - r8, lr}
 
diff --git a/builtin-unpack-objects.c b/builtin-unpack-objects.c
index 40b20f26e8..d2796b6309 100644
--- a/builtin-unpack-objects.c
+++ b/builtin-unpack-objects.c
@@ -19,7 +19,7 @@ static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict]
 static unsigned char buffer[4096];
 static unsigned int offset, len;
 static off_t consumed_bytes;
-static SHA_CTX ctx;
+static git_SHA_CTX ctx;
 
 /*
  * When running under --strict mode, objects whose reachability are
@@ -59,7 +59,7 @@ static void *fill(int min)
 	if (min > sizeof(buffer))
 		die("cannot fill %d bytes", min);
 	if (offset) {
-		SHA1_Update(&ctx, buffer, offset);
+		git_SHA1_Update(&ctx, buffer, offset);
 		memmove(buffer, buffer + offset, len);
 		offset = 0;
 	}
@@ -539,10 +539,10 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 		/* We don't take any non-flag arguments now.. Maybe some day */
 		usage(unpack_usage);
 	}
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 	unpack_all();
-	SHA1_Update(&ctx, buffer, offset);
-	SHA1_Final(sha1, &ctx);
+	git_SHA1_Update(&ctx, buffer, offset);
+	git_SHA1_Final(sha1, &ctx);
 	if (strict)
 		write_rest();
 	if (hashcmp(fill(20), sha1))
diff --git a/cache.h b/cache.h
index 7027c896bf..9f4e5c0d45 100644
--- a/cache.h
+++ b/cache.h
@@ -6,8 +6,14 @@
 #include "hash.h"
 
 #include SHA1_HEADER
-#include <zlib.h>
+#ifndef git_SHA_CTX
+#define git_SHA_CTX	SHA_CTX
+#define git_SHA1_Init	SHA1_Init
+#define git_SHA1_Update	SHA1_Update
+#define git_SHA1_Final	SHA1_Final
+#endif
 
+#include <zlib.h>
 #if defined(NO_DEFLATE_BOUND) || ZLIB_VERNUM < 0x1200
 #define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
 #endif
diff --git a/csum-file.c b/csum-file.c
index bb70c75ee1..717d29fc03 100644
--- a/csum-file.c
+++ b/csum-file.c
@@ -36,11 +36,11 @@ int sha1close(struct sha1file *f, unsigned char *result, unsigned int flags)
 	unsigned offset = f->offset;
 
 	if (offset) {
-		SHA1_Update(&f->ctx, f->buffer, offset);
+		git_SHA1_Update(&f->ctx, f->buffer, offset);
 		sha1flush(f, f->buffer, offset);
 		f->offset = 0;
 	}
-	SHA1_Final(f->buffer, &f->ctx);
+	git_SHA1_Final(f->buffer, &f->ctx);
 	if (result)
 		hashcpy(result, f->buffer);
 	if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {
@@ -82,7 +82,7 @@ int sha1write(struct sha1file *f, void *buf, unsigned int count)
 		buf = (char *) buf + nr;
 		left -= nr;
 		if (!left) {
-			SHA1_Update(&f->ctx, data, offset);
+			git_SHA1_Update(&f->ctx, data, offset);
 			sha1flush(f, data, offset);
 			offset = 0;
 		}
@@ -105,7 +105,7 @@ struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp
 	f->tp = tp;
 	f->name = name;
 	f->do_crc = 0;
-	SHA1_Init(&f->ctx);
+	git_SHA1_Init(&f->ctx);
 	return f;
 }
 
diff --git a/csum-file.h b/csum-file.h
index 72c9487f4f..9e13342eb3 100644
--- a/csum-file.h
+++ b/csum-file.h
@@ -7,7 +7,7 @@ struct progress;
 struct sha1file {
 	int fd;
 	unsigned int offset;
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	off_t total;
 	struct progress *tp;
 	const char *name;
diff --git a/diff.c b/diff.c
index 7c982b4947..4e4e439e03 100644
--- a/diff.c
+++ b/diff.c
@@ -3087,7 +3087,7 @@ static void diff_summary(FILE *file, struct diff_filepair *p)
 }
 
 struct patch_id_t {
-	SHA_CTX *ctx;
+	git_SHA_CTX *ctx;
 	int patchlen;
 };
 
@@ -3115,7 +3115,7 @@ static void patch_id_consume(void *priv, char *line, unsigned long len)
 
 	new_len = remove_space(line, len);
 
-	SHA1_Update(data->ctx, line, new_len);
+	git_SHA1_Update(data->ctx, line, new_len);
 	data->patchlen += new_len;
 }
 
@@ -3124,11 +3124,11 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 {
 	struct diff_queue_struct *q = &diff_queued_diff;
 	int i;
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	struct patch_id_t data;
 	char buffer[PATH_MAX * 4 + 20];
 
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 	memset(&data, 0, sizeof(struct patch_id_t));
 	data.ctx = &ctx;
 
@@ -3190,7 +3190,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 					len2, p->two->path,
 					len1, p->one->path,
 					len2, p->two->path);
-		SHA1_Update(&ctx, buffer, len1);
+		git_SHA1_Update(&ctx, buffer, len1);
 
 		xpp.flags = XDF_NEED_MINIMAL;
 		xecfg.ctxlen = 3;
@@ -3199,7 +3199,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 			      &xpp, &xecfg, &ecb);
 	}
 
-	SHA1_Final(sha1, &ctx);
+	git_SHA1_Final(sha1, &ctx);
 	return 0;
 }
 
diff --git a/fast-import.c b/fast-import.c
index ab6689a64d..3c035a5788 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -845,7 +845,7 @@ static int oecmp (const void *a_, const void *b_)
 static char *create_index(void)
 {
 	static char tmpfile[PATH_MAX];
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	struct sha1file *f;
 	struct object_entry **idx, **c, **last, *e;
 	struct object_entry_pool *o;
@@ -882,17 +882,17 @@ static char *create_index(void)
 	idx_fd = xmkstemp(tmpfile);
 	f = sha1fd(idx_fd, tmpfile);
 	sha1write(f, array, 256 * sizeof(int));
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 	for (c = idx; c != last; c++) {
 		uint32_t offset = htonl((*c)->offset);
 		sha1write(f, &offset, 4);
 		sha1write(f, (*c)->sha1, sizeof((*c)->sha1));
-		SHA1_Update(&ctx, (*c)->sha1, 20);
+		git_SHA1_Update(&ctx, (*c)->sha1, 20);
 	}
 	sha1write(f, pack_data->sha1, sizeof(pack_data->sha1));
 	sha1close(f, NULL, CSUM_FSYNC);
 	free(idx);
-	SHA1_Final(pack_data->sha1, &ctx);
+	git_SHA1_Final(pack_data->sha1, &ctx);
 	return tmpfile;
 }
 
@@ -1033,15 +1033,15 @@ static int store_object(
 	unsigned char hdr[96];
 	unsigned char sha1[20];
 	unsigned long hdrlen, deltalen;
-	SHA_CTX c;
+	git_SHA_CTX c;
 	z_stream s;
 
 	hdrlen = sprintf((char*)hdr,"%s %lu", typename(type),
 		(unsigned long)dat->len) + 1;
-	SHA1_Init(&c);
-	SHA1_Update(&c, hdr, hdrlen);
-	SHA1_Update(&c, dat->buf, dat->len);
-	SHA1_Final(sha1, &c);
+	git_SHA1_Init(&c);
+	git_SHA1_Update(&c, hdr, hdrlen);
+	git_SHA1_Update(&c, dat->buf, dat->len);
+	git_SHA1_Final(sha1, &c);
 	if (sha1out)
 		hashcpy(sha1out, sha1);
 
diff --git a/http-push.c b/http-push.c
index c9dd9a1f64..42f4d78e54 100644
--- a/http-push.c
+++ b/http-push.c
@@ -126,7 +126,7 @@ struct transfer_request
 	char errorstr[CURL_ERROR_SIZE];
 	long http_code;
 	unsigned char real_sha1[20];
-	SHA_CTX c;
+	git_SHA_CTX c;
 	z_stream stream;
 	int zret;
 	int rename;
@@ -209,7 +209,7 @@ static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 		request->stream.next_out = expn;
 		request->stream.avail_out = sizeof(expn);
 		request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
-		SHA1_Update(&request->c, expn,
+		git_SHA1_Update(&request->c, expn,
 			    sizeof(expn) - request->stream.avail_out);
 	} while (request->stream.avail_in && request->zret == Z_OK);
 	data_received++;
@@ -270,7 +270,7 @@ static void start_fetch_loose(struct transfer_request *request)
 
 	inflateInit(&request->stream);
 
-	SHA1_Init(&request->c);
+	git_SHA1_Init(&request->c);
 
 	url = xmalloc(strlen(remote->url) + 50);
 	request->url = xmalloc(strlen(remote->url) + 50);
@@ -310,7 +310,7 @@ static void start_fetch_loose(struct transfer_request *request)
 	if (prev_read == -1) {
 		memset(&request->stream, 0, sizeof(request->stream));
 		inflateInit(&request->stream);
-		SHA1_Init(&request->c);
+		git_SHA1_Init(&request->c);
 		if (prev_posn>0) {
 			prev_posn = 0;
 			lseek(request->local_fileno, 0, SEEK_SET);
@@ -742,7 +742,7 @@ static void finish_request(struct transfer_request *request)
 				fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 
 			inflateEnd(&request->stream);
-			SHA1_Final(request->real_sha1, &request->c);
+			git_SHA1_Final(request->real_sha1, &request->c);
 			if (request->zret != Z_STREAM_END) {
 				unlink(request->tmpfile);
 			} else if (hashcmp(request->obj->sha1, request->real_sha1)) {
diff --git a/http-walker.c b/http-walker.c
index 9dc6b27b45..7271c7d19d 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -36,7 +36,7 @@ struct object_request
 	char errorstr[CURL_ERROR_SIZE];
 	long http_code;
 	unsigned char real_sha1[20];
-	SHA_CTX c;
+	git_SHA_CTX c;
 	z_stream stream;
 	int zret;
 	int rename;
@@ -83,7 +83,7 @@ static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 		obj_req->stream.next_out = expn;
 		obj_req->stream.avail_out = sizeof(expn);
 		obj_req->zret = inflate(&obj_req->stream, Z_SYNC_FLUSH);
-		SHA1_Update(&obj_req->c, expn,
+		git_SHA1_Update(&obj_req->c, expn,
 			    sizeof(expn) - obj_req->stream.avail_out);
 	} while (obj_req->stream.avail_in && obj_req->zret == Z_OK);
 	data_received++;
@@ -144,7 +144,7 @@ static void start_object_request(struct walker *walker,
 
 	inflateInit(&obj_req->stream);
 
-	SHA1_Init(&obj_req->c);
+	git_SHA1_Init(&obj_req->c);
 
 	url = xmalloc(strlen(obj_req->repo->base) + 51);
 	obj_req->url = xmalloc(strlen(obj_req->repo->base) + 51);
@@ -184,7 +184,7 @@ static void start_object_request(struct walker *walker,
 	if (prev_read == -1) {
 		memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 		inflateInit(&obj_req->stream);
-		SHA1_Init(&obj_req->c);
+		git_SHA1_Init(&obj_req->c);
 		if (prev_posn>0) {
 			prev_posn = 0;
 			lseek(obj_req->local, 0, SEEK_SET);
@@ -244,7 +244,7 @@ static void finish_object_request(struct object_request *obj_req)
 	}
 
 	inflateEnd(&obj_req->stream);
-	SHA1_Final(obj_req->real_sha1, &obj_req->c);
+	git_SHA1_Final(obj_req->real_sha1, &obj_req->c);
 	if (obj_req->zret != Z_STREAM_END) {
 		unlink(obj_req->tmpfile);
 		return;
diff --git a/index-pack.c b/index-pack.c
index 530d820370..2e4c0885f2 100644
--- a/index-pack.c
+++ b/index-pack.c
@@ -67,7 +67,7 @@ static struct progress *progress;
 static unsigned char input_buffer[4096];
 static unsigned int input_offset, input_len;
 static off_t consumed_bytes;
-static SHA_CTX input_ctx;
+static git_SHA_CTX input_ctx;
 static uint32_t input_crc32;
 static int input_fd, output_fd, pack_fd;
 
@@ -119,7 +119,7 @@ static void flush(void)
 	if (input_offset) {
 		if (output_fd >= 0)
 			write_or_die(output_fd, input_buffer, input_offset);
-		SHA1_Update(&input_ctx, input_buffer, input_offset);
+		git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 		memmove(input_buffer, input_buffer + input_offset, input_len);
 		input_offset = 0;
 	}
@@ -188,7 +188,7 @@ static char *open_pack_file(char *pack_name)
 		output_fd = -1;
 		pack_fd = input_fd;
 	}
-	SHA1_Init(&input_ctx);
+	git_SHA1_Init(&input_ctx);
 	return pack_name;
 }
 
@@ -588,7 +588,7 @@ static void parse_pack_objects(unsigned char *sha1)
 
 	/* Check pack integrity */
 	flush();
-	SHA1_Final(sha1, &input_ctx);
+	git_SHA1_Final(sha1, &input_ctx);
 	if (hashcmp(fill(20), sha1))
 		die("pack is corrupted (SHA1 mismatch)");
 	use(20);
diff --git a/mozilla-sha1/sha1.c b/mozilla-sha1/sha1.c
index 3f06b83567..95a4ebf496 100644
--- a/mozilla-sha1/sha1.c
+++ b/mozilla-sha1/sha1.c
@@ -35,9 +35,9 @@
 
 #include "sha1.h"
 
-static void shaHashBlock(SHA_CTX *ctx);
+static void shaHashBlock(moz_SHA_CTX *ctx);
 
-void SHA1_Init(SHA_CTX *ctx) {
+void moz_SHA1_Init(moz_SHA_CTX *ctx) {
   int i;
 
   ctx->lenW = 0;
@@ -56,7 +56,7 @@ void SHA1_Init(SHA_CTX *ctx) {
 }
 
 
-void SHA1_Update(SHA_CTX *ctx, const void *_dataIn, int len) {
+void moz_SHA1_Update(moz_SHA_CTX *ctx, const void *_dataIn, int len) {
   const unsigned char *dataIn = _dataIn;
   int i;
 
@@ -75,7 +75,7 @@ void SHA1_Update(SHA_CTX *ctx, const void *_dataIn, int len) {
 }
 
 
-void SHA1_Final(unsigned char hashout[20], SHA_CTX *ctx) {
+void moz_SHA1_Final(unsigned char hashout[20], moz_SHA_CTX *ctx) {
   unsigned char pad0x80 = 0x80;
   unsigned char pad0x00 = 0x00;
   unsigned char padlen[8];
@@ -91,10 +91,10 @@ void SHA1_Final(unsigned char hashout[20], SHA_CTX *ctx) {
   padlen[5] = (unsigned char)((ctx->sizeLo >> 16) & 255);
   padlen[6] = (unsigned char)((ctx->sizeLo >> 8) & 255);
   padlen[7] = (unsigned char)((ctx->sizeLo >> 0) & 255);
-  SHA1_Update(ctx, &pad0x80, 1);
+  moz_SHA1_Update(ctx, &pad0x80, 1);
   while (ctx->lenW != 56)
-    SHA1_Update(ctx, &pad0x00, 1);
-  SHA1_Update(ctx, padlen, 8);
+    moz_SHA1_Update(ctx, &pad0x00, 1);
+  moz_SHA1_Update(ctx, padlen, 8);
 
   /* Output hash
    */
@@ -106,13 +106,13 @@ void SHA1_Final(unsigned char hashout[20], SHA_CTX *ctx) {
   /*
    *  Re-initialize the context (also zeroizes contents)
    */
-  SHA1_Init(ctx);
+  moz_SHA1_Init(ctx);
 }
 
 
 #define SHA_ROT(X,n) (((X) << (n)) | ((X) >> (32-(n))))
 
-static void shaHashBlock(SHA_CTX *ctx) {
+static void shaHashBlock(moz_SHA_CTX *ctx) {
   int t;
   unsigned int A,B,C,D,E,TEMP;
 
diff --git a/mozilla-sha1/sha1.h b/mozilla-sha1/sha1.h
index 16f2d3d43c..aa48a46cf7 100644
--- a/mozilla-sha1/sha1.h
+++ b/mozilla-sha1/sha1.h
@@ -38,8 +38,13 @@ typedef struct {
   unsigned int W[80];
   int lenW;
   unsigned int sizeHi,sizeLo;
-} SHA_CTX;
+} moz_SHA_CTX;
 
-void SHA1_Init(SHA_CTX *ctx);
-void SHA1_Update(SHA_CTX *ctx, const void *dataIn, int len);
-void SHA1_Final(unsigned char hashout[20], SHA_CTX *ctx);
+void moz_SHA1_Init(moz_SHA_CTX *ctx);
+void moz_SHA1_Update(moz_SHA_CTX *ctx, const void *dataIn, int len);
+void moz_SHA1_Final(unsigned char hashout[20], moz_SHA_CTX *ctx);
+
+#define git_SHA_CTX	moz_SHA_CTX
+#define git_SHA1_Init	moz_SHA1_Init
+#define git_SHA1_Update	moz_SHA1_Update
+#define git_SHA1_Final	moz_SHA1_Final
diff --git a/pack-check.c b/pack-check.c
index f596bf2db5..90c33b1b84 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -47,7 +47,7 @@ static int verify_packfile(struct packed_git *p,
 {
 	off_t index_size = p->index_size;
 	const unsigned char *index_base = p->index_data;
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	unsigned char sha1[20], *pack_sig;
 	off_t offset = 0, pack_sig_ofs = p->pack_size - 20;
 	uint32_t nr_objects, i;
@@ -60,16 +60,16 @@ static int verify_packfile(struct packed_git *p,
 	 * immediately.
 	 */
 
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 	while (offset < pack_sig_ofs) {
 		unsigned int remaining;
 		unsigned char *in = use_pack(p, w_curs, offset, &remaining);
 		offset += remaining;
 		if (offset > pack_sig_ofs)
 			remaining -= (unsigned int)(offset - pack_sig_ofs);
-		SHA1_Update(&ctx, in, remaining);
+		git_SHA1_Update(&ctx, in, remaining);
 	}
-	SHA1_Final(sha1, &ctx);
+	git_SHA1_Final(sha1, &ctx);
 	pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
 	if (hashcmp(sha1, pack_sig))
 		err = error("%s SHA1 checksum mismatch",
@@ -135,7 +135,7 @@ int verify_pack(struct packed_git *p)
 {
 	off_t index_size;
 	const unsigned char *index_base;
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	unsigned char sha1[20];
 	int err = 0;
 	struct pack_window *w_curs = NULL;
@@ -146,9 +146,9 @@ int verify_pack(struct packed_git *p)
 	index_base = p->index_data;
 
 	/* Verify SHA1 sum of the index file */
-	SHA1_Init(&ctx);
-	SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
-	SHA1_Final(sha1, &ctx);
+	git_SHA1_Init(&ctx);
+	git_SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
+	git_SHA1_Final(sha1, &ctx);
 	if (hashcmp(sha1, index_base + index_size - 20))
 		err = error("Packfile index for %s SHA1 mismatch",
 			    p->pack_name);
diff --git a/pack-write.c b/pack-write.c
index 3621f1dd32..b426006c58 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -25,7 +25,7 @@ char *write_idx_file(char *index_name, struct pack_idx_entry **objects,
 	off_t last_obj_offset = 0;
 	uint32_t array[256];
 	int i, fd;
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	uint32_t index_version;
 
 	if (nr_objects) {
@@ -86,7 +86,7 @@ char *write_idx_file(char *index_name, struct pack_idx_entry **objects,
 	sha1write(f, array, 256 * 4);
 
 	/* compute the SHA1 hash of sorted object names. */
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 
 	/*
 	 * Write the actual SHA1 entries..
@@ -99,7 +99,7 @@ char *write_idx_file(char *index_name, struct pack_idx_entry **objects,
 			sha1write(f, &offset, 4);
 		}
 		sha1write(f, obj->sha1, 20);
-		SHA1_Update(&ctx, obj->sha1, 20);
+		git_SHA1_Update(&ctx, obj->sha1, 20);
 	}
 
 	if (index_version >= 2) {
@@ -140,7 +140,7 @@ char *write_idx_file(char *index_name, struct pack_idx_entry **objects,
 
 	sha1write(f, sha1, 20);
 	sha1close(f, NULL, CSUM_FSYNC);
-	SHA1_Final(sha1, &ctx);
+	git_SHA1_Final(sha1, &ctx);
 	return index_name;
 }
 
@@ -168,12 +168,12 @@ void fixup_pack_header_footer(int pack_fd,
 			 off_t partial_pack_offset)
 {
 	int aligned_sz, buf_sz = 8 * 1024;
-	SHA_CTX old_sha1_ctx, new_sha1_ctx;
+	git_SHA_CTX old_sha1_ctx, new_sha1_ctx;
 	struct pack_header hdr;
 	char *buf;
 
-	SHA1_Init(&old_sha1_ctx);
-	SHA1_Init(&new_sha1_ctx);
+	git_SHA1_Init(&old_sha1_ctx);
+	git_SHA1_Init(&new_sha1_ctx);
 
 	if (lseek(pack_fd, 0, SEEK_SET) != 0)
 		die("Failed seeking to start of %s: %s", pack_name, strerror(errno));
@@ -181,9 +181,9 @@ void fixup_pack_header_footer(int pack_fd,
 		die("Unable to reread header of %s: %s", pack_name, strerror(errno));
 	if (lseek(pack_fd, 0, SEEK_SET) != 0)
 		die("Failed seeking to start of %s: %s", pack_name, strerror(errno));
-	SHA1_Update(&old_sha1_ctx, &hdr, sizeof(hdr));
+	git_SHA1_Update(&old_sha1_ctx, &hdr, sizeof(hdr));
 	hdr.hdr_entries = htonl(object_count);
-	SHA1_Update(&new_sha1_ctx, &hdr, sizeof(hdr));
+	git_SHA1_Update(&new_sha1_ctx, &hdr, sizeof(hdr));
 	write_or_die(pack_fd, &hdr, sizeof(hdr));
 	partial_pack_offset -= sizeof(hdr);
 
@@ -198,7 +198,7 @@ void fixup_pack_header_footer(int pack_fd,
 			break;
 		if (n < 0)
 			die("Failed to checksum %s: %s", pack_name, strerror(errno));
-		SHA1_Update(&new_sha1_ctx, buf, n);
+		git_SHA1_Update(&new_sha1_ctx, buf, n);
 
 		aligned_sz -= n;
 		if (!aligned_sz)
@@ -207,11 +207,11 @@ void fixup_pack_header_footer(int pack_fd,
 		if (!partial_pack_sha1)
 			continue;
 
-		SHA1_Update(&old_sha1_ctx, buf, n);
+		git_SHA1_Update(&old_sha1_ctx, buf, n);
 		partial_pack_offset -= n;
 		if (partial_pack_offset == 0) {
 			unsigned char sha1[20];
-			SHA1_Final(sha1, &old_sha1_ctx);
+			git_SHA1_Final(sha1, &old_sha1_ctx);
 			if (hashcmp(sha1, partial_pack_sha1) != 0)
 				die("Unexpected checksum for %s "
 				    "(disk corruption?)", pack_name);
@@ -220,7 +220,7 @@ void fixup_pack_header_footer(int pack_fd,
 			 * pack, which also means making partial_pack_offset
 			 * big enough not to matter anymore.
 			 */
-			SHA1_Init(&old_sha1_ctx);
+			git_SHA1_Init(&old_sha1_ctx);
 			partial_pack_offset = ~partial_pack_offset;
 			partial_pack_offset -= MSB(partial_pack_offset, 1);
 		}
@@ -228,8 +228,8 @@ void fixup_pack_header_footer(int pack_fd,
 	free(buf);
 
 	if (partial_pack_sha1)
-		SHA1_Final(partial_pack_sha1, &old_sha1_ctx);
-	SHA1_Final(new_pack_sha1, &new_sha1_ctx);
+		git_SHA1_Final(partial_pack_sha1, &old_sha1_ctx);
+	git_SHA1_Final(new_pack_sha1, &new_sha1_ctx);
 	write_or_die(pack_fd, new_pack_sha1, 20);
 	fsync_or_die(pack_fd, pack_name);
 }
diff --git a/patch-id.c b/patch-id.c
index 9349bc5580..871f1d20c0 100644
--- a/patch-id.c
+++ b/patch-id.c
@@ -1,6 +1,6 @@
 #include "cache.h"
 
-static void flush_current_id(int patchlen, unsigned char *id, SHA_CTX *c)
+static void flush_current_id(int patchlen, unsigned char *id, git_SHA_CTX *c)
 {
 	unsigned char result[20];
 	char name[50];
@@ -8,10 +8,10 @@ static void flush_current_id(int patchlen, unsigned char *id, SHA_CTX *c)
 	if (!patchlen)
 		return;
 
-	SHA1_Final(result, c);
+	git_SHA1_Final(result, c);
 	memcpy(name, sha1_to_hex(id), 41);
 	printf("%s %s\n", sha1_to_hex(result), name);
-	SHA1_Init(c);
+	git_SHA1_Init(c);
 }
 
 static int remove_space(char *line)
@@ -31,10 +31,10 @@ static void generate_id_list(void)
 {
 	static unsigned char sha1[20];
 	static char line[1000];
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	int patchlen = 0;
 
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 	while (fgets(line, sizeof(line), stdin) != NULL) {
 		unsigned char n[20];
 		char *p = line;
@@ -67,7 +67,7 @@ static void generate_id_list(void)
 		/* Compute the sha without whitespace */
 		len = remove_space(line);
 		patchlen += len;
-		SHA1_Update(&ctx, line, len);
+		git_SHA1_Update(&ctx, line, len);
 	}
 	flush_current_id(patchlen, sha1, &ctx);
 }
diff --git a/ppc/sha1.c b/ppc/sha1.c
index 738e36c1e8..ec6a1926d4 100644
--- a/ppc/sha1.c
+++ b/ppc/sha1.c
@@ -10,10 +10,10 @@
 #include <string.h>
 #include "sha1.h"
 
-extern void sha1_core(uint32_t *hash, const unsigned char *p,
-		      unsigned int nblocks);
+extern void ppc_sha1_core(uint32_t *hash, const unsigned char *p,
+			  unsigned int nblocks);
 
-int SHA1_Init(SHA_CTX *c)
+int ppc_SHA1_Init(ppc_SHA_CTX *c)
 {
 	c->hash[0] = 0x67452301;
 	c->hash[1] = 0xEFCDAB89;
@@ -25,7 +25,7 @@ int SHA1_Init(SHA_CTX *c)
 	return 0;
 }
 
-int SHA1_Update(SHA_CTX *c, const void *ptr, unsigned long n)
+int ppc_SHA1_Update(ppc_SHA_CTX *c, const void *ptr, unsigned long n)
 {
 	unsigned long nb;
 	const unsigned char *p = ptr;
@@ -38,12 +38,12 @@ int SHA1_Update(SHA_CTX *c, const void *ptr, unsigned long n)
 				nb = n;
 			memcpy(&c->buf.b[c->cnt], p, nb);
 			if ((c->cnt += nb) == 64) {
-				sha1_core(c->hash, c->buf.b, 1);
+				ppc_sha1_core(c->hash, c->buf.b, 1);
 				c->cnt = 0;
 			}
 		} else {
 			nb = n >> 6;
-			sha1_core(c->hash, p, nb);
+			ppc_sha1_core(c->hash, p, nb);
 			nb <<= 6;
 		}
 		n -= nb;
@@ -52,7 +52,7 @@ int SHA1_Update(SHA_CTX *c, const void *ptr, unsigned long n)
 	return 0;
 }
 
-int SHA1_Final(unsigned char *hash, SHA_CTX *c)
+int ppc_SHA1_Final(unsigned char *hash, ppc_SHA_CTX *c)
 {
 	unsigned int cnt = c->cnt;
 
@@ -60,13 +60,13 @@ int SHA1_Final(unsigned char *hash, SHA_CTX *c)
 	if (cnt > 56) {
 		if (cnt < 64)
 			memset(&c->buf.b[cnt], 0, 64 - cnt);
-		sha1_core(c->hash, c->buf.b, 1);
+		ppc_sha1_core(c->hash, c->buf.b, 1);
 		cnt = 0;
 	}
 	if (cnt < 56)
 		memset(&c->buf.b[cnt], 0, 56 - cnt);
 	c->buf.l[7] = c->len;
-	sha1_core(c->hash, c->buf.b, 1);
+	ppc_sha1_core(c->hash, c->buf.b, 1);
 	memcpy(hash, c->hash, 20);
 	return 0;
 }
diff --git a/ppc/sha1.h b/ppc/sha1.h
index c3c51aa4d4..c405f734c2 100644
--- a/ppc/sha1.h
+++ b/ppc/sha1.h
@@ -5,7 +5,7 @@
  */
 #include <stdint.h>
 
-typedef struct sha_context {
+typedef struct {
 	uint32_t hash[5];
 	uint32_t cnt;
 	uint64_t len;
@@ -13,8 +13,13 @@ typedef struct sha_context {
 		unsigned char b[64];
 		uint64_t l[8];
 	} buf;
-} SHA_CTX;
+} ppc_SHA_CTX;
 
-int SHA1_Init(SHA_CTX *c);
-int SHA1_Update(SHA_CTX *c, const void *p, unsigned long n);
-int SHA1_Final(unsigned char *hash, SHA_CTX *c);
+int ppc_SHA1_Init(ppc_SHA_CTX *c);
+int ppc_SHA1_Update(ppc_SHA_CTX *c, const void *p, unsigned long n);
+int ppc_SHA1_Final(unsigned char *hash, ppc_SHA_CTX *c);
+
+#define git_SHA_CTX	ppc_SHA_CTX
+#define git_SHA1_Init	ppc_SHA1_Init
+#define git_SHA1_Update	ppc_SHA1_Update
+#define git_SHA1_Final	ppc_SHA1_Final
diff --git a/ppc/sha1ppc.S b/ppc/sha1ppc.S
index f132696ee7..1711eef6e7 100644
--- a/ppc/sha1ppc.S
+++ b/ppc/sha1ppc.S
@@ -162,8 +162,8 @@ add RE(t),RE(t),%r0;  rotlwi RB(t),RB(t),30
 	STEPUP4(fn, (t)+12, (s)+12,);	\
 	STEPUP4(fn, (t)+16, (s)+16, loadk)
 
-	.globl	sha1_core
-sha1_core:
+	.globl	ppc_sha1_core
+ppc_sha1_core:
 	stwu	%r1,-80(%r1)
 	stmw	%r13,4(%r1)
 
diff --git a/read-cache.c b/read-cache.c
index 5b1b3ad03b..901064bf1a 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1072,16 +1072,16 @@ struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
 
 static int verify_hdr(struct cache_header *hdr, unsigned long size)
 {
-	SHA_CTX c;
+	git_SHA_CTX c;
 	unsigned char sha1[20];
 
 	if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
 		return error("bad signature");
 	if (hdr->hdr_version != htonl(2))
 		return error("bad index version");
-	SHA1_Init(&c);
-	SHA1_Update(&c, hdr, size - 20);
-	SHA1_Final(sha1, &c);
+	git_SHA1_Init(&c);
+	git_SHA1_Update(&c, hdr, size - 20);
+	git_SHA1_Final(sha1, &c);
 	if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
 		return error("bad index file sha1 signature");
 	return 0;
@@ -1278,11 +1278,11 @@ int unmerged_index(const struct index_state *istate)
 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
 static unsigned long write_buffer_len;
 
-static int ce_write_flush(SHA_CTX *context, int fd)
+static int ce_write_flush(git_SHA_CTX *context, int fd)
 {
 	unsigned int buffered = write_buffer_len;
 	if (buffered) {
-		SHA1_Update(context, write_buffer, buffered);
+		git_SHA1_Update(context, write_buffer, buffered);
 		if (write_in_full(fd, write_buffer, buffered) != buffered)
 			return -1;
 		write_buffer_len = 0;
@@ -1290,7 +1290,7 @@ static int ce_write_flush(SHA_CTX *context, int fd)
 	return 0;
 }
 
-static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
+static int ce_write(git_SHA_CTX *context, int fd, void *data, unsigned int len)
 {
 	while (len) {
 		unsigned int buffered = write_buffer_len;
@@ -1312,7 +1312,7 @@ static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
 	return 0;
 }
 
-static int write_index_ext_header(SHA_CTX *context, int fd,
+static int write_index_ext_header(git_SHA_CTX *context, int fd,
 				  unsigned int ext, unsigned int sz)
 {
 	ext = htonl(ext);
@@ -1321,13 +1321,13 @@ static int write_index_ext_header(SHA_CTX *context, int fd,
 		(ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
 }
 
-static int ce_flush(SHA_CTX *context, int fd)
+static int ce_flush(git_SHA_CTX *context, int fd)
 {
 	unsigned int left = write_buffer_len;
 
 	if (left) {
 		write_buffer_len = 0;
-		SHA1_Update(context, write_buffer, left);
+		git_SHA1_Update(context, write_buffer, left);
 	}
 
 	/* Flush first if not enough space for SHA1 signature */
@@ -1338,7 +1338,7 @@ static int ce_flush(SHA_CTX *context, int fd)
 	}
 
 	/* Append the SHA1 signature at the end */
-	SHA1_Final(write_buffer + left, context);
+	git_SHA1_Final(write_buffer + left, context);
 	left += 20;
 	return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
 }
@@ -1392,7 +1392,7 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
 	}
 }
 
-static int ce_write_entry(SHA_CTX *c, int fd, struct cache_entry *ce)
+static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
 {
 	int size = ondisk_ce_size(ce);
 	struct ondisk_cache_entry *ondisk = xcalloc(1, size);
@@ -1416,7 +1416,7 @@ static int ce_write_entry(SHA_CTX *c, int fd, struct cache_entry *ce)
 
 int write_index(const struct index_state *istate, int newfd)
 {
-	SHA_CTX c;
+	git_SHA_CTX c;
 	struct cache_header hdr;
 	int i, err, removed;
 	struct cache_entry **cache = istate->cache;
@@ -1430,7 +1430,7 @@ int write_index(const struct index_state *istate, int newfd)
 	hdr.hdr_version = htonl(2);
 	hdr.hdr_entries = htonl(entries - removed);
 
-	SHA1_Init(&c);
+	git_SHA1_Init(&c);
 	if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
 		return -1;
 
diff --git a/rerere.c b/rerere.c
index 8447caeebc..121f911414 100644
--- a/rerere.c
+++ b/rerere.c
@@ -73,7 +73,7 @@ static int write_rr(struct string_list *rr, int out_fd)
 static int handle_file(const char *path,
 	 unsigned char *sha1, const char *output)
 {
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	char buf[1024];
 	int hunk_no = 0;
 	enum {
@@ -95,7 +95,7 @@ static int handle_file(const char *path,
 	}
 
 	if (sha1)
-		SHA1_Init(&ctx);
+		git_SHA1_Init(&ctx);
 
 	strbuf_init(&one, 0);
 	strbuf_init(&two,  0);
@@ -127,9 +127,9 @@ static int handle_file(const char *path,
 				fputs(">>>>>>>\n", out);
 			}
 			if (sha1) {
-				SHA1_Update(&ctx, one.buf ? one.buf : "",
+				git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 					    one.len + 1);
-				SHA1_Update(&ctx, two.buf ? two.buf : "",
+				git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 					    two.len + 1);
 			}
 			strbuf_reset(&one);
@@ -154,7 +154,7 @@ static int handle_file(const char *path,
 	if (out)
 		fclose(out);
 	if (sha1)
-		SHA1_Final(sha1, &ctx);
+		git_SHA1_Final(sha1, &ctx);
 	if (hunk != RR_CONTEXT) {
 		if (output)
 			unlink(output);
diff --git a/sha1_file.c b/sha1_file.c
index 70ff904717..7515987868 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2132,16 +2132,16 @@ static void write_sha1_file_prepare(const void *buf, unsigned long len,
                                     const char *type, unsigned char *sha1,
                                     char *hdr, int *hdrlen)
 {
-	SHA_CTX c;
+	git_SHA_CTX c;
 
 	/* Generate the header */
 	*hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
 
 	/* Sha1.. */
-	SHA1_Init(&c);
-	SHA1_Update(&c, hdr, *hdrlen);
-	SHA1_Update(&c, buf, len);
-	SHA1_Final(sha1, &c);
+	git_SHA1_Init(&c);
+	git_SHA1_Update(&c, hdr, *hdrlen);
+	git_SHA1_Update(&c, buf, len);
+	git_SHA1_Final(sha1, &c);
 }
 
 /*
diff --git a/test-sha1.c b/test-sha1.c
index 78d7e983a7..9b98d07c78 100644
--- a/test-sha1.c
+++ b/test-sha1.c
@@ -2,7 +2,7 @@
 
 int main(int ac, char **av)
 {
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	unsigned char sha1[20];
 	unsigned bufsz = 8192;
 	char *buffer;
@@ -20,7 +20,7 @@ int main(int ac, char **av)
 			die("OOPS");
 	}
 
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 
 	while (1) {
 		ssize_t sz, this_sz;
@@ -39,9 +39,9 @@ int main(int ac, char **av)
 		}
 		if (this_sz == 0)
 			break;
-		SHA1_Update(&ctx, buffer, this_sz);
+		git_SHA1_Update(&ctx, buffer, this_sz);
 	}
-	SHA1_Final(sha1, &ctx);
+	git_SHA1_Final(sha1, &ctx);
 	puts(sha1_to_hex(sha1));
 	exit(0);
 }