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fix: suggested changes

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This commit is contained in:
Md. Anisul Haque
2023-05-24 17:34:48 +05:30
parent 912c54bcac
commit 6e857edc7a
1 changed files with 92 additions and 70 deletions
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162
hashing/sha256.cpp
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@@ -93,17 +93,45 @@ uint32_t right_rotate(uint32_t n, size_t rotate) {
}
/**
* @brief Computes the final hash array
* @param padded_input Padded input string
* @return std::array<uint32_t, 8> The final hash array
* @brief Creates the message schedule array
* @param input Input string
* @param i Position of the first bit of the chunk
* @return std::array<uint32_t, 64> Message schedule array
*/
std::array<uint32_t, 8> compute_hash(const std::string &input) {
// Initialize array of hash values with first 32 bits of the fractional
// parts of the square roots of the first 8 primes 2..19
std::array<uint32_t, 8> hash = {0x6A09E667, 0xBB67AE85, 0x3C6EF372,
0xA54FF53A, 0x510E527F, 0x9B05688C,
0x1F83D9AB, 0x5BE0CD19};
std::array<uint32_t, 64> create_message_schedule_array(const std::string &input,
const size_t i) {
std::array<uint32_t, 64> blocks{};
// Copy chunk into first 16 words of the message schedule array
for (size_t j = 0; j < 16; ++j) {
blocks[j] =
(static_cast<uint8_t>(get_char(input, i + j * 4)) << 24) |
(static_cast<uint8_t>(get_char(input, i + j * 4 + 1)) << 16) |
(static_cast<uint8_t>(get_char(input, i + j * 4 + 2)) << 8) |
static_cast<uint8_t>(get_char(input, i + j * 4 + 3));
}
// Extend the first 16 words into remaining 48 words of the message schedule
// array
for (size_t j = 16; j < 64; ++j) {
uint32_t s0 = right_rotate(blocks[j - 15], 7) ^
right_rotate(blocks[j - 15], 18) ^ (blocks[j - 15] >> 3);
uint32_t s1 = right_rotate(blocks[j - 2], 17) ^
right_rotate(blocks[j - 2], 19) ^ (blocks[j - 2] >> 10);
blocks[j] = blocks[j - 16] + s0 + blocks[j - 7] + s1;
}
return blocks;
}
/**
* @brief Modifies the hash array
* @param hash Hash array to be modified
* @param blocks Message schedule array
* @return void
*/
void modify_hash(std::array<uint32_t, 8> &hash,
const std::array<uint32_t, 64> &blocks) {
// Initialize array of round constants with first 32 bits of the fractional
// parts of the cube roots of the first 64 primes 2..311
const std::array<uint32_t, 64> k = {
@@ -119,69 +147,63 @@ std::array<uint32_t, 8> compute_hash(const std::string &input) {
0x5B9CCA4F, 0x682E6FF3, 0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208,
0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2};
// Initialize working variables
uint32_t a = hash[0];
uint32_t b = hash[1];
uint32_t c = hash[2];
uint32_t d = hash[3];
uint32_t e = hash[4];
uint32_t f = hash[5];
uint32_t g = hash[6];
uint32_t h = hash[7];
// Compression function main loop
for (size_t j = 0; j < 64; ++j) {
uint32_t s1 =
right_rotate(e, 6) ^ right_rotate(e, 11) ^ right_rotate(e, 25);
uint32_t ch = (e & f) ^ (~e & g);
uint32_t temp1 = h + s1 + ch + k[j] + blocks[j];
uint32_t s0 =
right_rotate(a, 2) ^ right_rotate(a, 13) ^ right_rotate(a, 22);
uint32_t maj = (a & b) ^ (a & c) ^ (b & c);
uint32_t temp2 = s0 + maj;
h = g;
g = f;
f = e;
e = d + temp1;
d = c;
c = b;
b = a;
a = temp1 + temp2;
}
// Update hash values
hash[0] += a;
hash[1] += b;
hash[2] += c;
hash[3] += d;
hash[4] += e;
hash[5] += f;
hash[6] += g;
hash[7] += h;
}
/**
* @brief Computes the final hash array
* @param input Input string
* @return std::array<uint32_t, 8> The final hash array
*/
std::array<uint32_t, 8> compute_hash(const std::string &input) {
// Initialize array of hash values with first 32 bits of the fractional
// parts of the square roots of the first 8 primes 2..19
std::array<uint32_t, 8> hash = {0x6A09E667, 0xBB67AE85, 0x3C6EF372,
0xA54FF53A, 0x510E527F, 0x9B05688C,
0x1F83D9AB, 0x5BE0CD19};
// Process message in successive 512-bit (64-byte) chunks
for (size_t i = 0; i < compute_padded_size(input.length()); i += 64) {
std::array<uint32_t, 64> blocks{};
// Copy chunk into first 16 words of the message schedule array
for (size_t j = 0; j < 16; ++j) {
blocks[j] =
(static_cast<uint8_t>(get_char(input, i + j * 4)) << 24) |
(static_cast<uint8_t>(get_char(input, i + j * 4 + 1)) << 16) |
(static_cast<uint8_t>(get_char(input, i + j * 4 + 2)) << 8) |
static_cast<uint8_t>(get_char(input, i + j * 4 + 3));
}
for (size_t j = 16; j < 64; ++j) {
uint32_t s0 = right_rotate(blocks[j - 15], 7) ^
right_rotate(blocks[j - 15], 18) ^
(blocks[j - 15] >> 3);
uint32_t s1 = right_rotate(blocks[j - 2], 17) ^
right_rotate(blocks[j - 2], 19) ^
(blocks[j - 2] >> 10);
blocks[j] = blocks[j - 16] + s0 + blocks[j - 7] + s1;
}
// Initialize working variables
uint32_t a = hash[0];
uint32_t b = hash[1];
uint32_t c = hash[2];
uint32_t d = hash[3];
uint32_t e = hash[4];
uint32_t f = hash[5];
uint32_t g = hash[6];
uint32_t h = hash[7];
// Compression function main loop
for (size_t j = 0; j < 64; ++j) {
uint32_t s1 =
right_rotate(e, 6) ^ right_rotate(e, 11) ^ right_rotate(e, 25);
uint32_t ch = (e & f) ^ (~e & g);
uint32_t temp1 = h + s1 + ch + k[j] + blocks[j];
uint32_t s0 =
right_rotate(a, 2) ^ right_rotate(a, 13) ^ right_rotate(a, 22);
uint32_t maj = (a & b) ^ (a & c) ^ (b & c);
uint32_t temp2 = s0 + maj;
h = g;
g = f;
f = e;
e = d + temp1;
d = c;
c = b;
b = a;
a = temp1 + temp2;
}
// Update hash values
hash[0] += a;
hash[1] += b;
hash[2] += c;
hash[3] += d;
hash[4] += e;
hash[5] += f;
hash[6] += g;
hash[7] += h;
modify_hash(hash, create_message_schedule_array(input, i));
}
return hash;