IT WAS ALL IN HIS HEAD

server/src/crypto/bcrypt.cpp

@@ -5,18 +5,20 @@ static const uint32_t bcrypt_ciphertext[6] = {
     0x64657253, 0x63727944, 0x6f756274
 };
 
-std::string sosc::cgc::bcrypt_hash(const std::string& input) {
-    std::string salt = csprng::next_bytes(16),
-        input_t = input.substr(0, 72);
+std::string sosc::cgc::bcrypt_hash_raw
+    (const std::string& input, const std::string& salt, uint32_t cost) 
+{
+    std::string salt_t = salt.substr(0, 16),
+                input_t = input.substr(0, 72);
         
     uint32_t ctext[6];
     std::memcpy(ctext, bcrypt_ciphertext, 6 * sizeof(uint32_t));
     
     Blowfish bfish;
-    bfish.SetEksKey(salt, input);
-    for(int i = 0; i < BCRYPT_COST; ++i) {
-        bfish.SetKey(input.c_str(), input.length());
-        bfish.SetKey(salt.c_str(), salt.length());
+    bfish.SetEksKey(salt_t, input_t);
+    for(uint32_t i = 0; i < 1 << (cost % 32); ++i) {
+        bfish.SetKey(input_t.c_str(), input_t.length());
+        bfish.SetKey(salt_t.c_str(), salt_t.length());
     }
     
     for(int i = 0; i < 64; ++i)
@@ -33,9 +35,47 @@ std::string sosc::cgc::bcrypt_hash(const std::string& input) {
     
     std::stringstream stream;
     stream << "$2b$" 
-           << (BCRYPT_COST < 10 ? "0" : "") << BCRYPT_COST
-           << "$" << base64_encode(salt, true)
+           << (cost < 10 ? "0" : "") << cost
+           << "$" << base64_encode(salt_t, true)
            << base64_encode(ct_hash, true);
            
     return stream.str();
 }
+
+std::string sosc::cgc::bcrypt_hash(const std::string& input) {
+    return bcrypt_hash_raw(input, sosc::csprng::next_bytes(16), BCRYPT_COST);
+}
+
+bool sosc::cgc::bcrypt_check
+    (const std::string& input, const std::string& hash) 
+{
+    if(hash.length() != 60 && !str::starts(hash, "$2b$"))
+        return false;
+    
+    auto parts = str::split(hash, '$');
+    if(parts.size() != 4)
+        return false;
+    parts.erase(parts.begin());
+    
+    if(parts[1].length() != 2)
+        return false;
+    
+    int cost;
+    try {
+        cost = std::stoi(parts[1], 0, 10);
+    } catch(...) {
+        return false;
+    }
+    
+    std::string salt = parts[2].substr(0, 22),
+        input_t = input.substr(0, 72),
+        hash_chk = bcrypt_hash_raw(input_t, base64_decode(salt, true), cost);
+    
+    // timing safe compare DO NOT OPTIMIZE
+    bool success = true;
+    for(int i = 0; i < hash.length(); ++i)
+        if(hash[i] != hash_chk[i])
+            success = false;
+    
+    return success;
+}

server/src/crypto/bcrypt.hpp

@@ -7,13 +7,17 @@
 #include "base64.hpp"
 #include "bfish.hpp"
 #include "../utils/csprng.hpp"
+#include "../utils/string.hpp"
 
 #define BCRYPT_COST 10
 
 namespace sosc {
 namespace cgc {
 std::string bcrypt_hash(const std::string& input);
-bool bcrypt_check(std::string input, std::string hash);
+std::string bcrypt_hash_raw
+    (const std::string& input, const std::string& salt, uint32_t cost);
+
+bool bcrypt_check(const std::string& input, const std::string& hash);
 }}
 
 #endif

server/src/crypto/bfish.hpp

@@ -25,7 +25,8 @@ private:
     uint32_t parr[18];
     uint32_t sbox[4][256];
     
-    friend std::string sosc::cgc::bcrypt_hash(const std::string&);
+    friend std::string sosc::cgc::bcrypt_hash_raw
+        (const std::string& input, const std::string& salt, uint32_t cost);
 };
 }}
 

server/src/main.cpp

@@ -10,6 +10,7 @@
 #include "crypto/bfish.hpp"
 #include "utils/csprng.hpp"
 #include "crypto/bcrypt.hpp"
+#include "utils/bigint.hpp"
 
 int main(int argc, char **argv) {
     //auto sock = sosc::TcpClient();
@@ -43,8 +44,12 @@ int main(int argc, char **argv) {
     uint32_t teest = sosc::csprng::next<uint32_t>();
     std::cout << std::hex << teest;*/
     
-    std::string hash = sosc::cgc::bcrypt_hash("test pwd");
-    std::cout << hash;
+    /*std::string hash = sosc::cgc::bcrypt_hash("test pwd");
+    std::cout << hash << std::endl;
+    std::cout << sosc::cgc::bcrypt_check("test pwd", hash);*/
+    
+    sosc::BigUInt bi;
+    bi.Parse("abcdef0", 10);
     
     return 0;
 }

server/src/utils/bigint.cpp

@@ -1,2 +1,102 @@
 #include "bigint.hpp"
 
+static bool is_hex_char(char c) {
+    return ((c >= 'a') && (c <= 'f'))
+        || ((c >= 'A') && (c <= 'F'))
+        || ((c >= '0') && (c <= '9'));
+}
+
+sosc::BigUInt::BigUInt() {
+    this->value = { 0 };
+}
+
+sosc::BigUInt::BigUInt(std::string hex_str, int byte_count) {
+    this->Parse(hex_str, byte_count);
+}
+
+bool sosc::BigUInt::Parse(std::string hex_str, int byte_count) {
+    if(hex_str.length() == 0)
+        hex_str = "00";
+    if(hex_str.length() % 2 != 0)
+        hex_str.insert(hex_str.begin(), '0');
+    
+    int str_byte_count = hex_str.length() / 2;
+    byte_count = std::max(byte_count, str_byte_count);
+    
+    this->value = std::vector<uint8_t>(byte_count, 0);
+    for(int i = 0; i < hex_str.length(); i += 2) {
+        if(!is_hex_char(hex_str[i]) || !is_hex_char(hex_str[i + 1]))
+            return false;
+        
+        this->value[str_byte_count - (i / 2) - 1] 
+            = std::stoi(hex_str.substr(i, 2), 0, 16);
+    }
+    
+    return true;
+}
+
+void sosc::BigUInt::Random(int byte_count) {
+    this->value = std::vector<uint8_t>(byte_count, 0);
+    std::string random_str = csprng::next_bytes(byte_count);
+    for(int i = 0; i < byte_count; ++i)
+        this->value[i] = random_str[i];
+}
+
+void sosc::BigUInt::RandomPrime(int byte_count) {
+    do {
+        this->Random(byte_count);
+        this->value[0] |= 0x01;
+        this->value[byte_count - 1] |= 0x80;
+    } while(!this->IsProbablePrime());
+}
+
+bool sosc::BigUInt::IsProbablePrime() const {
+    // TODO rabin-miller
+}
+
+std::tuple<sosc::BigUInt, sosc::BigUInt> sosc::BigUInt::DivideWithRemainder
+    (const BigUInt& num, const BigUInt& denom)
+{
+    if(num.IsZero())
+        return std::make_tuple(BigUInt(), BigUInt());
+    if(denom.IsZero())
+        throw "BigUInt division by zero";
+    if(denom.IsOne())
+        return std::make_tuple(num, BigUInt());
+    if(denom > num)
+        return std::make_tuple(BigUInt(), num);
+    
+    BigUInt quotient, remainder;
+    for(uint64_t i = num.ByteCount() * 8 - 1;; --i) {
+        remainder = remainder << 1;
+        remainder.SetBit(0, num.GetBit(i));
+        
+        if(remainder >= denom) {
+            remainder -= denom;
+            quotient.SetBit(i, true);
+        }
+        
+        if(i == 0)
+            break;
+    }
+    
+    return std::make_tuple(quotient, remainder);
+}
+
+sosc::BigUInt sosc::BigUInt::ModPow
+    (const BigUInt& base, const BigUInt& exp, const BigUInt& mod)
+{
+    BigUInt accum("1");
+    BigUInt x = exp;
+    BigUInt bpow = base;
+    
+    while(!x.IsZero()) {
+        if(!x.IsEven())
+            accum = (accum * bpow) % mod;
+        
+        x = x >> 1;
+        bpow = (bpow * bpow) % mod;
+    }
+    
+    return accum;
+}

server/src/utils/bigint.hpp

@@ -5,25 +5,58 @@
 #include <string>
 #include <vector>
 #include <cstdint>
+#include "csprng.hpp"
 
 namespace sosc {
-class BigInteger {
+class BigUInt {
 public:
-    BigInteger();
-    BigInteger(std::string hex_str, int byte_count = -1);
+    BigUInt();
+    BigUInt(std::string hex_str, int byte_count = -1);
+    bool Parse(std::string hex_str, int byte_count = -1);
+    void Random(int byte_count);
+    void RandomPrime(int byte_count);
     
-    inline size_t ByteCount() {
+    inline size_t ByteCount() const {
         return value.size();
     }
     
-    static std::tuple<BigInteger, BigInteger> DivideWithRemainder
-        (const BigInteger& num, const BigInteger& denom);
-        
-    static BigInteger ModPow
-        (const BigInteger& base, const BigInteger& exp, const BigInteger& mod);
-    
+    bool IsZero() const;
+    bool IsOne() const;
+    bool IsEven() const;
+    bool IsProbablePrime() const;
     
+    static std::tuple<BigUInt, BigUInt> DivideWithRemainder
+        (const BigUInt& num, const BigUInt& denom);
         
+    static BigUInt ModPow
+        (const BigUInt& base, const BigUInt& exp, const BigUInt& mod);
+    
+    void SetBit(uint64_t bit, bool value);
+    bool GetBit(uint64_t bit) const;
+        
+    BigUInt& operator +  (const BigUInt& rhs) const;
+    BigUInt& operator += (const BigUInt& rhs);
+    
+    BigUInt& operator -  (const BigUInt& rhs) const;
+    BigUInt& operator -= (const BigUInt& rhs);
+    
+    BigUInt& operator *  (const BigUInt& rhs) const;
+    BigUInt& operator *= (const BigUInt& rhs);
+    
+    BigUInt& operator /  (const BigUInt& rhs) const;
+    BigUInt& operator /= (const BigUInt& rhs);
+    
+    BigUInt& operator %  (const BigUInt& rhs) const;
+    
+    bool operator == (const BigUInt& rhs) const;
+    bool operator >  (const BigUInt& rhs) const;
+    bool operator >= (const BigUInt& rhs) const;
+    bool operator <  (const BigUInt& rhs) const;
+    bool operator <= (const BigUInt& rhs) const;
+    
+    BigUInt operator >> (const uint64_t& rhs) const;
+    BigUInt operator << (const uint64_t& rhs) const;
+    
     std::string ToString() const;
     inline operator std::string () const {
         return this->ToString();