SHA-512.cpp

#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long int int64 ;
typedef unsigned int int32;


typedef long long ll;
typedef pair<int64, int64> pii;
typedef vector<int64> vi;
typedef vector<bool> vb;
typedef vector<vi> vvi;
typedef vector<pii> vpi;

#define forl(a, b, c) for (int64(a) = (b); (a) < (c); (a)++)
#define fore(a, b, c) for (int64(a) = (b); (a) <= (c); (a)++)
#define ford(a, b, c) for (int64(a) = (b); (a) >= (c); --(a))
#define foreach(a, b) for (auto &(a) : (b))
#define reset(a, b) memset(a, b, sizeof(a))
#define all(v) v.begin(), v.end()

const char newl = '\n';
const int64 N = 2e5 + 10;
const int64 mod = 1e9+7;
const ll inf = 2e18;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int64 getRandomNumber(int64 l, int64 r) {return uniform_int_distribution<int64>(l, r)(rng);}

class SHA512
{
    int64 initA = 0x6a09e667f3bcc908;
    int64 initB = 0xbb67ae8584caa73b;
    int64 initC = 0x3c6ef372fe94f82b;
    int64 initD = 0xa54ff53a5f1d36f1;
    int64 initE = 0x510e527fade682d1;
    int64 initF = 0x9b05688c2b3e6c1f;
    int64 initG = 0x1f83d9abfb41bd6b;
    int64 initH = 0x5be0cd19137e2179;
    
    const int64 constants[80] = {
        0x428a2f98d728ae22, 0x7137449123ef65cd,
        0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc,
        0x3956c25bf348b538, 0x59f111f1b605d019,
        0x923f82a4af194f9b, 0xab1c5ed5da6d8118,
        0xd807aa98a3030242, 0x12835b0145706fbe,
        0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2,
        0x72be5d74f27b896f, 0x80deb1fe3b1696b1,
        0x9bdc06a725c71235, 0xc19bf174cf692694,
        0xe49b69c19ef14ad2, 0xefbe4786384f25e3,
        0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65,
        0x2de92c6f592b0275, 0x4a7484aa6ea6e483,
        0x5cb0a9dcbd41fbd4, 0x76f988da831153b5,
        0x983e5152ee66dfab, 0xa831c66d2db43210,
        0xb00327c898fb213f, 0xbf597fc7beef0ee4,
        0xc6e00bf33da88fc2, 0xd5a79147930aa725,
        0x06ca6351e003826f, 0x142929670a0e6e70,
        0x27b70a8546d22ffc, 0x2e1b21385c26c926,
        0x4d2c6dfc5ac42aed, 0x53380d139d95b3df,
        0x650a73548baf63de, 0x766a0abb3c77b2a8,
        0x81c2c92e47edaee6, 0x92722c851482353b,
        0xa2bfe8a14cf10364, 0xa81a664bbc423001,
        0xc24b8b70d0f89791, 0xc76c51a30654be30,
        0xd192e819d6ef5218, 0xd69906245565a910,
        0xf40e35855771202a, 0x106aa07032bbd1b8,
        0x19a4c116b8d2d0c8, 0x1e376c085141ab53,
        0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8,
        0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb,
        0x5b9cca4f7763e373, 0x682e6ff3d6b2b8a3,
        0x748f82ee5defb2fc, 0x78a5636f43172f60,
        0x84c87814a1f0ab72, 0x8cc702081a6439ec,
        0x90befffa23631e28, 0xa4506cebde82bde9,
        0xbef9a3f7b2c67915, 0xc67178f2e372532b,
        0xca273eceea26619c, 0xd186b8c721c0c207,
        0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178,
        0x06f067aa72176fba, 0x0a637dc5a2c898a6,
        0x113f9804bef90dae, 0x1b710b35131c471b,
        0x28db77f523047d84, 0x32caab7b40c72493,
        0x3c9ebe0a15c9bebc, 0x431d67c49c100d4c,
        0x4cc5d4becb3e42b6, 0x597f299cfc657e2a,
        0x5fcb6fab3ad6faec, 0x6c44198c4a475817
    };

    int64 Word[80];

    int64 majority(int64 a, int64 b, int64 c){ return (a & b) ^ (b & c) ^ (c & a);}
    int64 conditional(int64 e, int64 f, int64 g){ return (e & f) ^ (~e & g);}
    int64 rotateE(int64 e){ return rotate_right(e, 14) ^ rotate_right(e, 18) ^ rotate_right(e, 41);}
    int64 rotateA(int64 a){ return rotate_right(a, 28) ^ rotate_right(a, 34) ^ rotate_right(a, 39);}
    int64 rotate_right(int64 x, int64 n){return (x >> n) | (x << (64 - n));}

    string decToBin(int64 n)
    {
        string bin = "";
        while (n > 0){
            bin = (char)(n % 2 + '0') + bin;
            n /= 2;
        }
        while (bin.size() < 4) bin = '0' + bin;
        return bin;
    }

    string binToHex(string s)
    {
        string hex = "";
        for (int i = 0; i < s.size(); i += 4)
        {
            string k = s.substr(i, 4);
            if (k == "0000") hex += '0';
            else if (k == "0001") hex += '1';
            else if (k == "0010") hex += '2';
            else if (k == "0011") hex += '3';
            else if (k == "0100") hex += '4';
            else if (k == "0101") hex += '5';
            else if (k == "0110") hex += '6';
            else if (k == "0111") hex += '7';
            else if (k == "1000") hex += '8';
            else if (k == "1001") hex += '9';
            else if (k == "1010") hex += 'a';
            else if (k == "1011") hex += 'b';
            else if (k == "1100") hex += 'c';
            else if (k == "1101") hex += 'd';
            else if (k == "1110") hex += 'e';
            else if (k == "1111") hex += 'f';
        }
        return hex;
    }

    string hexToBin(string s)
    {
        string bin = "";
        for (int64 i = 0; i < s.size(); i++)
        {
            switch (s[i])
            {
            case '0': bin += "0000"; break;
            case '1': bin += "0001"; break;
            case '2': bin += "0010"; break;
            case '3': bin += "0011"; break;
            case '4': bin += "0100"; break;
            case '5': bin += "0101"; break;
            case '6': bin += "0110"; break;
            case '7': bin += "0111"; break;
            case '8': bin += "1000"; break;
            case '9': bin += "1001"; break;
            case 'A': bin += "1010"; break;
            case 'B': bin += "1011"; break;
            case 'C': bin += "1100"; break;
            case 'D': bin += "1101"; break;
            case 'E': bin += "1110"; break;
            case 'F': bin += "1111"; break;
            case 'a': bin += "1010"; break;
            case 'b': bin += "1011"; break;
            case 'c': bin += "1100"; break;
            case 'd': bin += "1101"; break;
            case 'e': bin += "1110"; break;
            case 'f': bin += "1111"; break;

            }
        }
        return bin;
    }
    string decimalToHex(int64 deci)
    {
        string bin = bitset<64>(deci).to_string();
        string hex = binToHex(bin);
        return hex;
    }


    void wordExpander(string b)
    {
        int64 wordA, wordB, wordC, wordD;
        for (int64 i = 0; i < b.length();i += 64) Word[i/64] = bitset<64>(b.substr(i, 64)).to_ullong();

        for (int64 i = 16; i < 80; i++){
            wordA = Word[i - 16];
            wordB = rotate_right(Word[i - 15], 1) ^ rotate_right(Word[i - 15], 8) ^ (Word[i - 15] >> 7);
            wordC = Word[i - 7];
            wordD = rotate_right(Word[i - 2], 19) ^ rotate_right(Word[i - 2], 61) ^ (Word[i - 2] >> 6);

            Word[i] = wordA + wordB + wordC + wordD;
        }
    }

    void compressionFunc(int64 a, int64 b, int64 c,int64 &d, int64 e, int64 f,int64 g, int64 &h, int64 K)
    {
        int64 T2 = h + conditional(e, f, g) + rotateE(e) + Word[K] + constants[K];
        int64 T1 = rotateA(a) + majority(a, b, c);

        h = T1 + T2;
        d = d + T2;
    }

public:

    string createDigest(string s)
    {

        string s_bin = "";

        for (int64 i = 0;i < s.size(); ++i) s_bin += bitset<8>(s[i]).to_string();
        

        int64 len = s_bin.length();
        string len_bin = std::bitset<128>(len).to_string();


        int64 padding;

        if (1024 - (s_bin.length() % 1024) >= 128) padding = 1024 - (s_bin.length() % 1024);
        else  padding = 2048 - (s_bin.length() % 1024);
    

       
        for (int64 i = 0; i < padding - 128; i++)
        {
            if ( i == 0 ) s_bin += "1";
            else s_bin += "0";
        }

    
        s_bin += len_bin;

        int64 blocks = s_bin.length() / 1024;
        string hashBlocks[blocks];


        for (int64 i = 0; i < s_bin.length(); i += 1024) hashBlocks[i/1024] = s_bin.substr(i, 1024);
        

        int64 A,B,C,D,E,F,G,H;

        for (int64 j = 0; j < blocks; ++j){

       
            wordExpander(hashBlocks[j]);

            A = initA; B = initB; C = initC; D = initD; E = initE; F = initF; G = initG;H = initH;
         
            for (int64 i = 0; i < 10; i++)
            {
                compressionFunc(A, B, C, D, E, F, G, H, i*8 + 0);
                compressionFunc(H, A, B, C, D, E, F, G, i*8 + 1);
                compressionFunc(G, H, A, B, C, D, E, F, i*8 + 2);
                compressionFunc(F, G, H, A, B, C, D, E, i*8 + 3);
                compressionFunc(E, F, G, H, A, B, C, D, i*8 + 4);
                compressionFunc(D, E, F, G, H, A, B, C, i*8 + 5);
                compressionFunc(C, D, E, F, G, H, A, B, i*8 + 6);
                compressionFunc(B, C, D, E, F, G, H, A, i*8 + 7);
            }

            A += initA; B += initB; C += initC; D += initD; E += initE; F += initF; G += initG; H += initH;

           
        }

        string digest = decimalToHex(A) + decimalToHex(B) + decimalToHex(C) + decimalToHex(D) + decimalToHex(E) + decimalToHex(F) + decimalToHex(G) + decimalToHex(H);

        return digest;
    }
};



int32_t main()
{
    string M ;
    cout << newl << "Enter the message " << newl;
    getline(cin,M);

    SHA512 sha;
    string digest = sha.createDigest(M);

    cout << newl << "SHA512 Digest is" << newl;
    cout << digest << newl;
    cout << newl;

    return 0;
}