0

Is there a library that's easy to setup and use with Visual Studio 2010 for AES encryption/decryption?

I've been fiddling with CryptoPP and it's endless link errors and iterator_level_not_equal error messages for an hour now, so I think it's time to look for an installer or a new lib.

Any suggestions?

2
Contributors
1
Reply
2
Views
5 Years
Discussion Span
Last Post by Narue
0

AES isn't especially difficult to implement from the specification. Ignoring the usual caveats of reinventing the wheel on important stuff like encryption, you could write your own class:

#ifndef JSW_AES_PROVIDER_H
#define JSW_AES_PROVIDER_H

#include <vector>

namespace jsw {
    namespace encryption {
        typedef std::vector<unsigned char> bytes_t;
        
        class aes_provider {
        public:
            aes_provider(bytes_t key) { reset(key); }

            void normalize(bytes_t& bytes);
            bytes_t encrypt(const bytes_t& bytes);
            bytes_t decrypt(const bytes_t& bytes);
        private:
            static bytes_t::value_type Sbox[][16];
            static bytes_t::value_type Sbox_inverse[][16];
            static bytes_t::value_type Rcon[][4];
        private:
            int Nb; // Input block length in 32-bit increments (always 4)
            int Nk; // Key length in 32-bit increments (4, 6, or 8)
            int Nr; // Number of rounds corresponding to key size (4:10, 6:12, 8:14)

            bytes_t key;                // Seed key
            std::vector<bytes_t> w;     // Key schedule
            std::vector<bytes_t> state; // State matrix

            void reset(bytes_t key);
            void key_expansion();
            void add_round_key(int round);
            void sub_bytes(bytes_t::value_type Sbox[][16]);
            void shift_rows();
            void inverse_shift_rows();
            void mix_columns();
            void inverse_mix_columns();
            bytes_t sub_word(bytes_t word);
            bytes_t rot_word(bytes_t word);
            unsigned char gfield_mul(unsigned char a, unsigned char b);
        };
    }
}

#endif
#include <stdexcept>
#include <vector>
#include "aes_provider.h"

namespace jsw {
    namespace encryption {
        void aes_provider::normalize(bytes_t& bytes)
        {
            // Add null padding to the input (modulo 128-bits for AES)
            while (bytes.size() % 16 != 0)
                bytes.push_back(0);
        }
        
        bytes_t aes_provider::encrypt(const bytes_t& bytes)
        {
            state = std::vector<bytes_t>(4, bytes_t(Nb));

            // Input to state
            for (int r = 0; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    state[r][c] = bytes[r + 4 * c];
            }

            add_round_key(0);

            for (int round = 1; round < Nr; round++) {
                sub_bytes(Sbox);
                shift_rows();
                mix_columns();
                add_round_key(round);
            }

            sub_bytes(Sbox);
            shift_rows();
            add_round_key(Nr);

            bytes_t output(4 * Nb);

            // State to output
            for (int r = 0; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    output[r + 4 * c] = state[r][c];
            }

            return output;
        }

        bytes_t aes_provider::decrypt(const bytes_t& bytes)
        {
            state = std::vector<bytes_t>(4, bytes_t(Nb));

            // Input to state
            for (int r = 0; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    state[r][c] = bytes[r + 4 * c];
            }

            add_round_key(Nr);

            for (int round = Nr - 1; round > 0; round--) {
                inverse_shift_rows();
                sub_bytes(Sbox_inverse);
                add_round_key(round);
                inverse_mix_columns();
            }

            inverse_shift_rows();
            sub_bytes(Sbox_inverse);
            add_round_key(0);

            bytes_t output(4 * Nb);

            // State to output
            for (int r = 0; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    output[r + 4 * c] = state[r][c];
            }

            return output;
        }

        bytes_t::value_type aes_provider::Sbox[][16] = {
            {0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76},
            {0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0},
            {0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15},
            {0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75},
            {0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84},
            {0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf},
            {0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8},
            {0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2},
            {0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73},
            {0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb},
            {0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79},
            {0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08},
            {0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a},
            {0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e},
            {0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf},
            {0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16} 
        };

        bytes_t::value_type aes_provider::Sbox_inverse[][16] = {
            {0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb},
            {0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb},
            {0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e},
            {0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25},
            {0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92},
            {0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84},
            {0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06},
            {0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b},
            {0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73},
            {0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e},
            {0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b},
            {0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4},
            {0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f},
            {0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef},
            {0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61},
            {0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d}
        };

        bytes_t::value_type aes_provider::Rcon[][4] = {
            {0x00, 0x00, 0x00, 0x00},  
            {0x01, 0x00, 0x00, 0x00},
            {0x02, 0x00, 0x00, 0x00},
            {0x04, 0x00, 0x00, 0x00},
            {0x08, 0x00, 0x00, 0x00},
            {0x10, 0x00, 0x00, 0x00},
            {0x20, 0x00, 0x00, 0x00},
            {0x40, 0x00, 0x00, 0x00},
            {0x80, 0x00, 0x00, 0x00},
            {0x1b, 0x00, 0x00, 0x00},
            {0x36, 0x00, 0x00, 0x00}
        };

        void aes_provider::reset(bytes_t key)
        {
            Nb = 4;

            switch (key.size()) {
            case 32:
                Nk = 8;
                Nr = 14;
                break;
            case 24:
                Nk = 6;
                Nr = 12;
                break;
            case 16:
                Nk = 4;
                Nr = 10;
                break;
            default:
                throw std::invalid_argument("Not a valid key size");
            }

            this->key = key;
            key_expansion();
        }

        void aes_provider::key_expansion()
        {
            bytes_t temp(4);

            w = std::vector<bytes_t>(Nb * (Nr + 1), bytes_t(4, 0));

            for (int i = 0; i < Nk; i++) {
                for (int byte = 0; byte < 4; byte++)
                    w[i][byte] = key[4 * i + byte];
            }

            for (int i = Nk; i < Nb * (Nr + 1); i++) {
                for (int byte = 0; byte < 4; byte++)
                    temp[byte] = w[i - 1][byte];

                if (i % Nk == 0) {
                    temp = sub_word(rot_word(temp));

                    for (int byte = 0; byte < 4; byte++)
                        temp[byte] ^= Rcon[i / Nk][byte];
                }
                else if (Nk > 6 && i % Nk == 4) {
                    temp = sub_word(temp);
                }

                for (int byte = 0; byte < 4; byte++)
                    w[i][byte] = w[i - Nk][byte] ^ temp[byte];
            }
        }

        void aes_provider::add_round_key(int round)
        {
            for (int r = 0; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    state[r][c] ^= w[round * 4 + c][r];
            }
        }

        void aes_provider::sub_bytes(bytes_t::value_type Sbox[][16])
        {
            for (int r = 0; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    state[r][c] = Sbox[state[r][c] >> 4][state[r][c] & 0x0f];
            }
        }

        void aes_provider::shift_rows()
        {
            std::vector<bytes_t> temp = state;

            for (int r = 1; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    state[r][c] = temp[r][(c + r) % Nb];
            }
        }

        void aes_provider::inverse_shift_rows()
        {
            std::vector<bytes_t> temp = state;

            for (int r = 1; r < 4; r++) {
                for (int c = 0; c < Nb; c++)
                    state[r][(c + r) % Nb] = temp[r][c];
            }
        }

        void aes_provider::mix_columns()
        {
            std::vector<bytes_t> temp = state;

            for (int c = 0; c < 4; ++c) {
                state[0][c] = gfield_mul(temp[0][c], 2) ^ gfield_mul(temp[1][c], 3) ^ temp[2][c] ^ temp[3][c];
                state[1][c] = temp[0][c] ^ gfield_mul(temp[1][c], 2) ^ gfield_mul(temp[2][c], 3) ^ temp[3][c];
                state[2][c] = temp[0][c] ^ temp[1][c] ^ gfield_mul(temp[2][c], 2) ^ gfield_mul(temp[3][c], 3);
                state[3][c] = gfield_mul(temp[0][c], 3) ^ temp[1][c] ^ temp[2][c] ^ gfield_mul(temp[3][c], 2);
            }
        }

        void aes_provider::inverse_mix_columns()
        {
            std::vector<bytes_t> temp = state;

            for (int c = 0; c < 4; ++c) {
                state[0][c] = 
                    gfield_mul(temp[0][c], 0x0e) ^ gfield_mul(temp[1][c], 0x0b) ^ 
                    gfield_mul(temp[2][c], 0x0d) ^ gfield_mul(temp[3][c], 0x09);
                state[1][c] = 
                    gfield_mul(temp[0][c], 0x09) ^ gfield_mul(temp[1][c], 0x0e) ^ 
                    gfield_mul(temp[2][c], 0x0b) ^ gfield_mul(temp[3][c], 0x0d);
                state[2][c] = 
                    gfield_mul(temp[0][c], 0x0d) ^ gfield_mul(temp[1][c], 0x09) ^ 
                    gfield_mul(temp[2][c], 0x0e) ^ gfield_mul(temp[3][c], 0x0b);
                state[3][c] =
                    gfield_mul(temp[0][c], 0x0b) ^ gfield_mul(temp[1][c], 0x0d) ^ 
                    gfield_mul(temp[2][c], 0x09) ^ gfield_mul(temp[3][c], 0x0e);
            }
        }

        bytes_t aes_provider::sub_word(bytes_t word)
        {
            bytes_t result(4);

            result[0] = Sbox[word[0] >> 4][word[0] & 0x0f];
            result[1] = Sbox[word[1] >> 4][word[1] & 0x0f];
            result[2] = Sbox[word[2] >> 4][word[2] & 0x0f];
            result[3] = Sbox[word[3] >> 4][word[3] & 0x0f];

            return result;
        }

        bytes_t aes_provider::rot_word(bytes_t word)
        {
            bytes_t result(4);

            result[0] = word[1];
            result[1] = word[2];
            result[2] = word[3];
            result[3] = word[0];

            return result;
        }

        unsigned char aes_provider::gfield_mul(unsigned char a, unsigned char b)
        {
            unsigned char prod = 0;

            for (int i = 0; i < 8; i++) {
                if ((b & 1) == 1)
                    prod ^= a;

                bool is_set = (a & 0x80) == 0x80;

                a <<= 1;

                if (is_set)
                    a ^= 0x1b;

                b >>= 1;
            }

            return prod;
        }
    }
}
#include <algorithm>
#include <climits>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <string>
#include "aes_provider.h"

using namespace jsw::encryption;
using namespace std;

bytes_t random_key(int size)
{
    bytes_t key;

    generate_n(back_inserter(key), size, []{ 
        return rand() % UCHAR_MAX;
    });

    return key;
}

class dump_bytes {
    const bytes_t& _bytes;
public:
    dump_bytes(const bytes_t& bytes): _bytes(bytes) {}
    
    friend ostream& operator<<(ostream& out, const dump_bytes& self)
    {
        for_each(self._bytes.begin(), self._bytes.end(), [&](unsigned b) {
            out<< std::hex << std::setw(3) << b;
        });
    }
};

int main()
{
    string line;

    cout<<"Input: ";

    if (getline(cin, line)) {
        bytes_t bytes(line.begin(), line.end());
        aes_provider cipher(random_key(32));

        cipher.normalize(bytes);
        cout<<"Before:  "<< dump_bytes(bytes) << '\n';
        bytes = cipher.encrypt(bytes);
        cout<<"After:   "<< dump_bytes(bytes) << '\n';
        bytes = cipher.decrypt(bytes);
        cout<<"Restore: "<< dump_bytes(bytes) << '\n';
    }
}

;)

This question has already been answered. Start a new discussion instead.
Have something to contribute to this discussion? Please be thoughtful, detailed and courteous, and be sure to adhere to our posting rules.