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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "anglebase/sha1.h"
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include "anglebase/sys_byteorder.h"
namespace angle
{
namespace base
{
// Implementation of SHA-1. Only handles data in byte-sized blocks,
// which simplifies the code a fair bit.
// Identifier names follow notation in FIPS PUB 180-3, where you'll
// also find a description of the algorithm:
// http://csrc.nist.gov/publications/fips/fips180-3/fips180-3_final.pdf
// Usage example:
//
// SecureHashAlgorithm sha;
// while(there is data to hash)
// sha.Update(moredata, size of data);
// sha.Final();
// memcpy(somewhere, sha.Digest(), 20);
//
// to reuse the instance of sha, call sha.Init();
// TODO(jhawkins): Replace this implementation with a per-platform
// implementation using each platform's crypto library. See
// http://crbug.com/47218
class SecureHashAlgorithm
{
public:
SecureHashAlgorithm() { Init(); }
static const int kDigestSizeBytes;
void Init();
void Update(const void *data, size_t nbytes);
void Final();
// 20 bytes of message digest.
const unsigned char *Digest() const { return reinterpret_cast<const unsigned char *>(H); }
private:
void Pad();
void Process();
uint32_t A, B, C, D, E;
uint32_t H[5];
union {
uint32_t W[80];
uint8_t M[64];
};
uint32_t cursor;
uint64_t l;
};
static inline uint32_t f(uint32_t t, uint32_t B, uint32_t C, uint32_t D)
{
if (t < 20)
{
return (B & C) | ((~B) & D);
}
else if (t < 40)
{
return B ^ C ^ D;
}
else if (t < 60)
{
return (B & C) | (B & D) | (C & D);
}
else
{
return B ^ C ^ D;
}
}
static inline uint32_t S(uint32_t n, uint32_t X)
{
return (X << n) | (X >> (32 - n));
}
static inline uint32_t K(uint32_t t)
{
if (t < 20)
{
return 0x5a827999;
}
else if (t < 40)
{
return 0x6ed9eba1;
}
else if (t < 60)
{
return 0x8f1bbcdc;
}
else
{
return 0xca62c1d6;
}
}
const int SecureHashAlgorithm::kDigestSizeBytes = 20;
void SecureHashAlgorithm::Init()
{
A = 0;
B = 0;
C = 0;
D = 0;
E = 0;
cursor = 0;
l = 0;
H[0] = 0x67452301;
H[1] = 0xefcdab89;
H[2] = 0x98badcfe;
H[3] = 0x10325476;
H[4] = 0xc3d2e1f0;
}
void SecureHashAlgorithm::Final()
{
Pad();
Process();
for (int t = 0; t < 5; ++t)
H[t] = ByteSwap(H[t]);
}
void SecureHashAlgorithm::Update(const void *data, size_t nbytes)
{
const uint8_t *d = reinterpret_cast<const uint8_t *>(data);
while (nbytes--)
{
M[cursor++] = *d++;
if (cursor >= 64)
Process();
l += 8;
}
}
void SecureHashAlgorithm::Pad()
{
M[cursor++] = 0x80;
if (cursor > 64 - 8)
{
// pad out to next block
while (cursor < 64)
M[cursor++] = 0;
Process();
}
while (cursor < 64 - 8)
M[cursor++] = 0;
M[cursor++] = (l >> 56) & 0xff;
M[cursor++] = (l >> 48) & 0xff;
M[cursor++] = (l >> 40) & 0xff;
M[cursor++] = (l >> 32) & 0xff;
M[cursor++] = (l >> 24) & 0xff;
M[cursor++] = (l >> 16) & 0xff;
M[cursor++] = (l >> 8) & 0xff;
M[cursor++] = l & 0xff;
}
void SecureHashAlgorithm::Process()
{
uint32_t t;
// Each a...e corresponds to a section in the FIPS 180-3 algorithm.
// a.
//
// W and M are in a union, so no need to memcpy.
// memcpy(W, M, sizeof(M));
for (t = 0; t < 16; ++t)
W[t] = ByteSwap(W[t]);
// b.
for (t = 16; t < 80; ++t)
W[t] = S(1, W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]);
// c.
A = H[0];
B = H[1];
C = H[2];
D = H[3];
E = H[4];
// d.
for (t = 0; t < 80; ++t)
{
uint32_t TEMP = S(5, A) + f(t, B, C, D) + E + W[t] + K(t);
E = D;
D = C;
C = S(30, B);
B = A;
A = TEMP;
}
// e.
H[0] += A;
H[1] += B;
H[2] += C;
H[3] += D;
H[4] += E;
cursor = 0;
}
std::string SHA1HashString(const std::string &str)
{
char hash[SecureHashAlgorithm::kDigestSizeBytes];
SHA1HashBytes(reinterpret_cast<const unsigned char *>(str.c_str()), str.length(),
reinterpret_cast<unsigned char *>(hash));
return std::string(hash, SecureHashAlgorithm::kDigestSizeBytes);
}
void SHA1HashBytes(const unsigned char *data, size_t len, unsigned char *hash)
{
SecureHashAlgorithm sha;
sha.Update(data, len);
sha.Final();
memcpy(hash, sha.Digest(), SecureHashAlgorithm::kDigestSizeBytes);
}
} // namespace base
} // namespace angle
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