diff --git a/hashing/sha256.cpp b/hashing/sha256.cpp index b5449dee3..3ce02446a 100644 --- a/hashing/sha256.cpp +++ b/hashing/sha256.cpp @@ -12,9 +12,12 @@ * used for authenticating software packages and secure password hashing. */ +#include /// For std::array #include /// For assert #include /// For uint8_t, uint32_t and uint64_t data types +#include /// For std::setfill and std::setw #include /// For IO operations +#include /// For std::stringstream /** * @namespace hashing @@ -28,41 +31,11 @@ namespace hashing { */ namespace sha256 { /** - * @brief Rotates the bits of a 32-bit unsigned integer - * @param n Integer to rotate - * @param rotate Number of bits to rotate - * @return uint32_t The rotated integer + * @brief Pads the input string to be a multiple of 512-bits + * @param input Input string + * @return std::string The padded input string */ -uint32_t rightRotate(uint32_t n, size_t rotate) { - return (n >> rotate) | (n << (32 - rotate)); -} - -/** - * @brief The SHA-256 algorithm - * @param input The input string to hash - * @return std::string The final hash value - */ -std::string sha256(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 - uint32_t hash[8] = {0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, - 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19}; - - // 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 uint32_t k[64] = { - 0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5, 0x3956C25B, 0x59F111F1, - 0x923F82A4, 0xAB1C5ED5, 0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3, - 0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174, 0xE49B69C1, 0xEFBE4786, - 0x0FC19DC6, 0x240CA1CC, 0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA, - 0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7, 0xC6E00BF3, 0xD5A79147, - 0x06CA6351, 0x14292967, 0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13, - 0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85, 0xA2BFE8A1, 0xA81A664B, - 0xC24B8B70, 0xC76C51A3, 0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070, - 0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5, 0x391C0CB3, 0x4ED8AA4A, - 0x5B9CCA4F, 0x682E6FF3, 0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208, - 0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2}; - +std::string prepare_input(std::string input) { // Pre-processing std::string padded_input = input; uint64_t input_size = input.length() * 8; // Message length in bits @@ -78,9 +51,51 @@ std::string sha256(const std::string &input) { padded_input += static_cast((input_size >> (i - 8)) & 0xFF); } + return padded_input; +} + +/** + * @brief Rotates the bits of a 32-bit unsigned integer + * @param n Integer to rotate + * @param rotate Number of bits to rotate + * @return uint32_t The rotated integer + */ +uint32_t right_rotate(uint32_t n, size_t rotate) { + return (n >> rotate) | (n << (32 - rotate)); +} + +/** + * @brief The SHA-256 algorithm + * @param input The input string to hash + * @return std::string The final hash value + */ +std::string sha256(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 hash = {0x6A09E667, 0xBB67AE85, 0x3C6EF372, + 0xA54FF53A, 0x510E527F, 0x9B05688C, + 0x1F83D9AB, 0x5BE0CD19}; + + // 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 k = { + 0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5, 0x3956C25B, 0x59F111F1, + 0x923F82A4, 0xAB1C5ED5, 0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3, + 0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174, 0xE49B69C1, 0xEFBE4786, + 0x0FC19DC6, 0x240CA1CC, 0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA, + 0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7, 0xC6E00BF3, 0xD5A79147, + 0x06CA6351, 0x14292967, 0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13, + 0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85, 0xA2BFE8A1, 0xA81A664B, + 0xC24B8B70, 0xC76C51A3, 0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070, + 0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5, 0x391C0CB3, 0x4ED8AA4A, + 0x5B9CCA4F, 0x682E6FF3, 0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208, + 0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2}; + + const std::string padded_input = prepare_input(input); + // Process message in successive 512-bit (64-byte) chunks for (size_t i = 0; i < padded_input.length(); i += 64) { - uint32_t blocks[64]; + std::array blocks; // Copy chunk into first 16 words of the message schedule array for (size_t j = 0; j < 16; ++j) { @@ -92,11 +107,11 @@ std::string sha256(const std::string &input) { } for (size_t j = 16; j < 64; ++j) { - uint32_t s0 = rightRotate(blocks[j - 15], 7) ^ - rightRotate(blocks[j - 15], 18) ^ + uint32_t s0 = right_rotate(blocks[j - 15], 7) ^ + right_rotate(blocks[j - 15], 18) ^ (blocks[j - 15] >> 3); - uint32_t s1 = rightRotate(blocks[j - 2], 17) ^ - rightRotate(blocks[j - 2], 19) ^ + 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; } @@ -114,11 +129,11 @@ std::string sha256(const std::string &input) { // Compression function main loop for (size_t j = 0; j < 64; ++j) { uint32_t s1 = - rightRotate(e, 6) ^ rightRotate(e, 11) ^ rightRotate(e, 25); + 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 = - rightRotate(a, 2) ^ rightRotate(a, 13) ^ rightRotate(a, 22); + 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; @@ -146,11 +161,11 @@ std::string sha256(const std::string &input) { // Convert the hash to a hexadecimal string std::string result; for (size_t i = 0; i < 8; ++i) { - for (int j = 0; j < 4; ++j) { - uint8_t byte = (hash[i] >> (24 - j * 8)) & 0xFF; - char buf[3]; - sprintf(buf, "%02x", byte); - result += buf; + for (size_t j = 0; j < 4; ++j) { + uint32_t byte = (hash[i] >> (24 - j * 8)) & 0xFF; + std::stringstream ss; + ss << std::hex << std::setfill('0') << std::setw(2) << byte; + result += ss.str(); } }