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authorSanto Cariotti <santo@dcariotti.me>2021-01-12 13:37:15 +0100
committerSanto Cariotti <santo@dcariotti.me>2021-01-12 13:41:17 +0100
commit3992face1ede1ac8da081dfff4f2aa14ab1facce (patch)
tree48aa698ddba1b4d6815bc1551a0907bfc17449d8 /src
parentefe3267e26566c4e0286263e9ee563ada26b8c2d (diff)
feat: add sha256 algorithm
Diffstat (limited to 'src')
-rw-r--r--src/main.cc10
-rw-r--r--src/sha256.cc165
2 files changed, 175 insertions, 0 deletions
diff --git a/src/main.cc b/src/main.cc
new file mode 100644
index 0000000..9f01c14
--- /dev/null
+++ b/src/main.cc
@@ -0,0 +1,10 @@
+#include<iostream>
+#include "sha256.h"
+
+int main(int argc, char** argv) {
+ auto sha = hmacsha256::SHA256(argv[1]);
+ sha.digest();
+ std::cout << sha.hexdigest();
+
+ return 0;
+}
diff --git a/src/sha256.cc b/src/sha256.cc
new file mode 100644
index 0000000..7790f8a
--- /dev/null
+++ b/src/sha256.cc
@@ -0,0 +1,165 @@
+#include "sha256.h"
+#include<cstring> // used for memset
+#include<sstream> // used for stringstream
+#include<iomanip> // used for setfill and setw
+
+hmacsha256::SHA256::SHA256(const uint8_t* data, uint32_t length) {
+ init(data, length);
+}
+
+void hmacsha256::SHA256::init(const uint8_t* data, uint32_t length) {
+ message_l_ = bit_len_ = 0;
+ vars_[0] = 0x6a09e667;
+ vars_[1] = 0xbb67ae85;
+ vars_[2] = 0x3c6ef372;
+ vars_[3] = 0xa54ff53a;
+ vars_[4] = 0x510e527f;
+ vars_[5] = 0x9b05688c;
+ vars_[6] = 0x1f83d9ab;
+ vars_[7] = 0x5be0cd19;
+
+ for(size_t i = 0; i < length; ++i) {
+ message_[message_l_++] = data[i];
+ if(message_l_ == 64) {
+ transform();
+
+ bit_len_ += 512;
+ message_l_ = 0;
+ }
+ }
+}
+
+hmacsha256::SHA256::SHA256(const std::string& data) {
+ init(reinterpret_cast<const uint8_t*> (data.c_str()), data.size());
+}
+
+uint8_t* hmacsha256::SHA256::digest() {
+ uint8_t* hash = new uint8_t[32];
+
+ pad();
+ bigendian(hash);
+
+ for(uint32_t i = 0; i < 32; ++i) {
+ digest_[i] = hash[i];
+ }
+
+ return hash;
+}
+
+std::string hmacsha256::SHA256::hexdigest() {
+ std::stringstream s;
+ s << std::setfill('0') << std::hex;
+
+ for(uint8_t i = 0 ; i < 32 ; i++) {
+ s << std::setw(2) << (unsigned int) digest_[i];
+ }
+
+ return s.str();
+}
+
+uint32_t hmacsha256::SHA256::ch(uint32_t x, uint32_t y, uint32_t z) {
+ return (x & y) ^ (~x & z);
+}
+
+uint32_t hmacsha256::SHA256::maj(uint32_t x, uint32_t y, uint32_t z) {
+ return (x & (y | z)) | (y & z);
+}
+
+uint32_t hmacsha256::SHA256::rotr(uint32_t x, uint32_t n) {
+ return (x >> n) | (x << (32-n));
+}
+
+uint32_t hmacsha256::SHA256::big_sigma0(uint32_t x) {
+ return SHA256::rotr(x, 2) ^ SHA256::rotr(x, 13) ^ SHA256::rotr(x, 22);
+}
+
+uint32_t hmacsha256::SHA256::big_sigma1(uint32_t x) {
+ return SHA256::rotr(x, 6) ^ SHA256::rotr(x, 11) ^ SHA256::rotr(x, 25);
+}
+
+uint32_t hmacsha256::SHA256::sigma0(uint32_t x) {
+ return SHA256::rotr(x, 7) ^ SHA256::rotr(x, 18) ^ (x >> 3);
+}
+
+uint32_t hmacsha256::SHA256::sigma1(uint32_t x) {
+ return SHA256::rotr(x, 17) ^ SHA256::rotr(x, 19) ^ (x >> 10);
+}
+
+void hmacsha256::SHA256::transform() {
+ uint32_t m[64];
+ uint32_t h[8];
+
+ for(uint8_t i = 0, j = 0; i < 16; ++i, j += 4) {
+ m[i] = (message_[j] << 24) | (message_[j + 1] << 16) | (message_[j + 2] << 8) | (message_[j + 3]);
+ }
+
+ for(uint8_t i = 16; i < 64; ++i) {
+ m[i] = SHA256::sigma1(m[i - 2]) + m[i - 7] + SHA256::sigma0(m[i - 15]) + m[i - 16];
+ }
+
+ for(uint8_t i = 0; i < 8; ++i)
+ h[i] = vars_[i];
+
+ for(uint8_t i = 0; i < 64; ++i) {
+ auto S1 = SHA256::big_sigma1(h[4]);
+ auto S0 = SHA256::big_sigma0(h[0]);
+ auto t1 = h[7] + S1 + SHA256::ch(h[4], h[5], h[6]) + K[i] + m[i];
+ auto t2 = S0 + SHA256::maj(h[0], h[1], h[2]);
+ h[7] = h[6];
+ h[6] = h[5];
+ h[5] = h[4];
+ h[4] = h[3] + t1;
+ h[3] = h[2];
+ h[2] = h[1];
+ h[1] = h[0];
+ h[0] = t1 + t2;
+ }
+
+ for(uint8_t i = 0; i < 8; ++i) {
+ vars_[i]+=h[i];
+ }
+
+}
+
+void hmacsha256::SHA256::pad() {
+ // start of scanning
+ uint64_t i = message_l_;
+
+ // end of scanning
+ uint8_t j = (i < 56) ? 56 : 64;
+
+ // append '1' bit at the end of the block
+ message_[i++] = 0x80;
+
+ // append '0' bit, j times
+ while(i < j) message_[i++] = 0x00;
+
+ if(message_l_ >= 56) {
+ transform();
+ memset(message_, 0, 56);
+ }
+
+ bit_len_ += message_l_ * 8;
+ message_[63] = bit_len_;
+ message_[62] = bit_len_ >> 8;
+ message_[61] = bit_len_ >> 16;
+ message_[60] = bit_len_ >> 24;
+ message_[59] = bit_len_ >> 32;
+ message_[58] = bit_len_ >> 40;
+ message_[57] = bit_len_ >> 48;
+ message_[56] = bit_len_ >> 56;
+ transform();
+}
+
+void hmacsha256::SHA256::bigendian(uint8_t* hash) {
+ for (uint32_t i = 0; i < 4; ++i) {
+ hash[i] = (vars_[0] >> (24 - i * 8)) & 0x000000ff;
+ hash[i + 4] = (vars_[1] >> (24 - i * 8)) & 0x000000ff;
+ hash[i + 8] = (vars_[2] >> (24 - i * 8)) & 0x000000ff;
+ hash[i + 12] = (vars_[3] >> (24 - i * 8)) & 0x000000ff;
+ hash[i + 16] = (vars_[4] >> (24 - i * 8)) & 0x000000ff;
+ hash[i + 20] = (vars_[5] >> (24 - i * 8)) & 0x000000ff;
+ hash[i + 24] = (vars_[6] >> (24 - i * 8)) & 0x000000ff;
+ hash[i + 28] = (vars_[7] >> (24 - i * 8)) & 0x000000ff;
+ }
+}