--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/other/sha1sum.c	Sat Aug 25 14:25:22 2012 -0500
@@ -0,0 +1,185 @@
+/* vi: set sw=4 ts=4:
+ *
+ * sha1sum.c - Calculate sha1 cryptographic hash for input.
+ *
+ * Copyright 2007 Rob Landley <rob@landley.net>
+ *
+ * Based on the public domain SHA-1 in C by Steve Reid <steve@edmweb.com>
+ * from http://www.mirrors.wiretapped.net/security/cryptography/hashes/sha1/
+ *
+ * Not in SUSv3.
+
+USE_SHA1SUM(NEWTOY(sha1sum, NULL, TOYFLAG_USR|TOYFLAG_BIN))
+
+config SHA1SUM
+	bool "sha1sum"
+	default y
+	help
+	  usage: sha1sum [file...]
+
+	  Calculate sha1 hash of files (or stdin).
+*/
+
+#include <toys.h>
+
+struct sha1 {
+	uint32_t state[5];
+	uint32_t oldstate[5];
+	uint64_t count;
+	union {
+		unsigned char c[64];
+		uint32_t i[16];
+	} buffer;
+};
+
+static void sha1_init(struct sha1 *this);
+static void sha1_transform(struct sha1 *this);
+static void sha1_update(struct sha1 *this, char *data, unsigned int len);
+static void sha1_final(struct sha1 *this, char digest[20]);
+
+#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
+
+// blk0() and blk() perform the initial expand.
+// The idea of expanding during the round function comes from SSLeay
+#if 1
+#define blk0(i) (block[i] = (rol(block[i],24)&0xFF00FF00) \
+	|(rol(block[i],8)&0x00FF00FF))
+#else	// big endian?
+#define blk0(i) block[i]
+#endif
+#define blk(i) (block[i&15] = rol(block[(i+13)&15]^block[(i+8)&15] \
+	^block[(i+2)&15]^block[i&15],1))
+
+static const uint32_t rconsts[]={0x5A827999,0x6ED9EBA1,0x8F1BBCDC,0xCA62C1D6};
+
+// Hash a single 512-bit block. This is the core of the algorithm.
+
+static void sha1_transform(struct sha1 *this)
+{
+	int i, j, k, count;
+	uint32_t *block = this->buffer.i;
+	uint32_t *rot[5], *temp;
+
+	// Copy context->state[] to working vars
+	for (i=0; i<5; i++) {
+		this->oldstate[i] = this->state[i];
+		rot[i] = this->state + i;
+	}
+	// 4 rounds of 20 operations each.
+	for (i=count=0; i<4; i++) {
+		for (j=0; j<20; j++) {
+			uint32_t work;
+
+			work = *rot[2] ^ *rot[3];
+			if (!i) work = (work & *rot[1]) ^ *rot[3];
+			else {
+				if (i==2)
+					work = ((*rot[1]|*rot[2])&*rot[3])|(*rot[1]&*rot[2]);
+				else work ^= *rot[1];
+			}
+			if (!i && j<16) work += blk0(count);
+			else work += blk(count);
+			*rot[4] += work + rol(*rot[0],5) + rconsts[i];
+			*rot[1] = rol(*rot[1],30);
+
+			// Rotate by one for next time.
+			temp = rot[4];
+			for (k=4; k; k--) rot[k] = rot[k-1];
+			*rot = temp;
+			count++;
+		}
+	}
+	// Add the previous values of state[]
+	for (i=0; i<5; i++) this->state[i] += this->oldstate[i];
+}
+
+
+// Initialize a struct sha1.
+
+static void sha1_init(struct sha1 *this)
+{
+	/* SHA1 initialization constants */
+	this->state[0] = 0x67452301;
+	this->state[1] = 0xEFCDAB89;
+	this->state[2] = 0x98BADCFE;
+	this->state[3] = 0x10325476;
+	this->state[4] = 0xC3D2E1F0;
+	this->count = 0;
+}
+
+// Fill the 64-byte working buffer and call sha1_transform() when full.
+
+void sha1_update(struct sha1 *this, char *data, unsigned int len)
+{
+	unsigned int i, j;
+
+	j = this->count & 63;
+	this->count += len;
+
+	// Enough data to process a frame?
+	if ((j + len) > 63) {
+		i = 64-j;
+		memcpy(this->buffer.c + j, data, i);
+		sha1_transform(this);
+		for ( ; i + 63 < len; i += 64) {
+			memcpy(this->buffer.c, data + i, 64);
+			sha1_transform(this);
+		}
+		j = 0;
+	} else i = 0;
+	// Grab remaining chunk
+	memcpy(this->buffer.c + j, data + i, len - i);
+}
+
+// Add padding and return the message digest.
+
+void sha1_final(struct sha1 *this, char digest[20])
+{
+	uint64_t count = this->count << 3;
+	unsigned int i;
+	char buf;
+
+	// End the message by appending a "1" bit to the data, ending with the
+	// message size (in bits, big endian), and adding enough zero bits in
+	// between to pad to the end of the next 64-byte frame.
+	//
+	// Since our input up to now has been in whole bytes, we can deal with
+	// bytes here too.
+
+	buf = 0x80;
+	do {
+		sha1_update(this, &buf, 1);
+		buf = 0;
+	} while ((this->count & 63) != 56);
+	for (i = 0; i < 8; i++)
+	  this->buffer.c[56+i] = count >> (8*(7-i));
+	sha1_transform(this);
+
+	for (i = 0; i < 20; i++)
+		digest[i] = this->state[i>>2] >> ((3-(i & 3)) * 8);
+	// Wipe variables.  Cryptogropher paranoia.
+	memset(this, 0, sizeof(struct sha1));
+}
+
+// Callback for loopfiles()
+
+static void do_sha1(int fd, char *name)
+{
+	struct sha1 this;
+	int len;
+
+	sha1_init(&this);
+	for (;;) {
+		len = read(fd, toybuf, sizeof(toybuf));
+		if (len<1) break;
+		sha1_update(&this, toybuf, len);
+	}
+	sha1_final(&this, toybuf);
+	for (len = 0; len < 20; len++) printf("%02x", toybuf[len]);
+	printf("  %s\n", name);
+}
+
+void sha1sum_main(void)
+{
+	loopfiles(toys.optargs, do_sha1);
+}