DES Class Reference

#include <DES.hpp>

Public Member Functions
void	decryptBlock (BIT64 *block)
void	decrypt (unsigned char *data, size_t size)
void	roundFunction (BIT64 *src)
	DES round function. XORs src[0..3] with TP(SBOX(E(src[4..7]))). More...
void	SBOX (BIT64 *src)
void	E (BIT64 *src)
	Expansion (E). Expands upper four 8-bits (32b) into eight 6-bits (48b). More...
void	TP (BIT64 *src)
	Transposition (P-BOX). More...
void	IP (BIT64 *src)
	Initial permutation (IP). More...
void	FP (BIT64 *src)
	Final permutation (IP^-1). More...

Member Function Documentation

decrypt()

void DES::decrypt	(	unsigned char *	data,
		size_t	size
	)

{
    BIT64* p = (BIT64*)data;
    size_t i;
 
    for (i = 0; i*8 < size; i += 8)
        decryptBlock(p);
}

References decryptBlock().

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decryptBlock()

void DES::decryptBlock

(

BIT64 *

block

)

{
    IP(block);
    roundFunction(block);
    FP(block);
}

References FP(), IP(), and roundFunction().

Referenced by GRF::decodeFull(), GRF::decodeHeader(), and decrypt().

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E()

void DES::E

(

BIT64 *

src

)

Expansion (E). Expands upper four 8-bits (32b) into eight 6-bits (48b).

{
    BIT64 tmp = { { 0 } };
 
    tmp.b[0] = ((src->b[7]<<5) | (src->b[4]>>3)) & 0x3f;    // ..0 vutsr
    tmp.b[1] = ((src->b[4]<<1) | (src->b[5]>>7)) & 0x3f;    // ..srqpo n
    tmp.b[2] = ((src->b[4]<<5) | (src->b[5]>>3)) & 0x3f;    // ..o nmlkj
    tmp.b[3] = ((src->b[5]<<1) | (src->b[6]>>7)) & 0x3f;    // ..kjihg f
    tmp.b[4] = ((src->b[5]<<5) | (src->b[6]>>3)) & 0x3f;    // ..g fedcb
    tmp.b[5] = ((src->b[6]<<1) | (src->b[7]>>7)) & 0x3f;    // ..cba98 7
    tmp.b[6] = ((src->b[6]<<5) | (src->b[7]>>3)) & 0x3f;    // ..8 76543
    tmp.b[7] = ((src->b[7]<<1) | (src->b[4]>>7)) & 0x3f;    // ..43210 v
 
    *src = tmp;
}

References BIT64::b.

Referenced by roundFunction().

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FP()

void DES::FP

(

BIT64 *

src

)

Final permutation (IP^-1).

{
    BIT64 tmp = {{0}};
 
    std::vector<uint8_t> fp_table = {
            40,  8, 48, 16, 56, 24, 64, 32,
            39,  7, 47, 15, 55, 23, 63, 31,
            38,  6, 46, 14, 54, 22, 62, 30,
            37,  5, 45, 13, 53, 21, 61, 29,
            36,  4, 44, 12, 52, 20, 60, 28,
            35,  3, 43, 11, 51, 19, 59, 27,
            34,  2, 42, 10, 50, 18, 58, 26,
            33,  1, 41,  9, 49, 17, 57, 25,
    };
 
    size_t i;
    for( i = 0; i < fp_table.size(); ++i )
    {
        uint8_t j = fp_table.at(i) - 1;
        if (src->b[(j >> 3) & 7] &  mask[j & 7])
            tmp .b[(i >> 3) & 7] |= mask[i & 7];
    }
 
    *src = tmp;
}

References BIT64::b, and mask.

Referenced by decryptBlock().

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IP()

void DES::IP

(

BIT64 *

src

)

Initial permutation (IP).

{
    BIT64 tmp = {{0}};
 
    std::vector<uint8_t> ip_table = {
        58, 50, 42, 34, 26, 18, 10,  2,
        60, 52, 44, 36, 28, 20, 12,  4,
        62, 54, 46, 38, 30, 22, 14,  6,
        64, 56, 48, 40, 32, 24, 16,  8,
        57, 49, 41, 33, 25, 17,  9,  1,
        59, 51, 43, 35, 27, 19, 11,  3,
        61, 53, 45, 37, 29, 21, 13,  5,
        63, 55, 47, 39, 31, 23, 15,  7,
    };
 
    size_t i;
    for( i = 0; i < ip_table.size(); ++i )
    {
        uint8_t j = ip_table.at(i) - 1;
        if (src->b[(j >> 3) & 7] &  mask[j & 7])
            tmp.b[(i >> 3) & 7] |= mask[i & 7];
    }
 
    *src = tmp;
}

References BIT64::b, and mask.

Referenced by decryptBlock().

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roundFunction()

void DES::roundFunction

(

BIT64 *

src

)

DES round function. XORs src[0..3] with TP(SBOX(E(src[4..7]))).

{
    BIT64 tmp = *src;
    E(&tmp);
    SBOX(&tmp);
    TP(&tmp);
 
    src->b[0] ^= tmp.b[4];
    src->b[1] ^= tmp.b[5];
    src->b[2] ^= tmp.b[6];
    src->b[3] ^= tmp.b[7];
}

References BIT64::b, E(), SBOX(), and TP().

Referenced by decryptBlock().

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SBOX()

void DES::SBOX

(

BIT64 *

src

)

{
    BIT64 tmp = {{0}};
 
    std::vector<std::vector<uint8_t>> s_table = {
            {
                    0xef, 0x03, 0x41, 0xfd, 0xd8, 0x74, 0x1e, 0x47,  0x26, 0xef, 0xfb, 0x22, 0xb3, 0xd8, 0x84, 0x1e,
                    0x39, 0xac, 0xa7, 0x60, 0x62, 0xc1, 0xcd, 0xba,  0x5c, 0x96, 0x90, 0x59, 0x05, 0x3b, 0x7a, 0x85,
                    0x40, 0xfd, 0x1e, 0xc8, 0xe7, 0x8a, 0x8b, 0x21,  0xda, 0x43, 0x64, 0x9f, 0x2d, 0x14, 0xb1, 0x72,
                    0xf5, 0x5b, 0xc8, 0xb6, 0x9c, 0x37, 0x76, 0xec,  0x39, 0xa0, 0xa3, 0x05, 0x52, 0x6e, 0x0f, 0xd9,
            },{
                    0xa7, 0xdd, 0x0d, 0x78, 0x9e, 0x0b, 0xe3, 0x95,  0x60, 0x36, 0x36, 0x4f, 0xf9, 0x60, 0x5a, 0xa3,
                    0x11, 0x24, 0xd2, 0x87, 0xc8, 0x52, 0x75, 0xec,  0xbb, 0xc1, 0x4c, 0xba, 0x24, 0xfe, 0x8f, 0x19,
                    0xda, 0x13, 0x66, 0xaf, 0x49, 0xd0, 0x90, 0x06,  0x8c, 0x6a, 0xfb, 0x91, 0x37, 0x8d, 0x0d, 0x78,
                    0xbf, 0x49, 0x11, 0xf4, 0x23, 0xe5, 0xce, 0x3b,  0x55, 0xbc, 0xa2, 0x57, 0xe8, 0x22, 0x74, 0xce,
            },{
                    0x2c, 0xea, 0xc1, 0xbf, 0x4a, 0x24, 0x1f, 0xc2,  0x79, 0x47, 0xa2, 0x7c, 0xb6, 0xd9, 0x68, 0x15,
                    0x80, 0x56, 0x5d, 0x01, 0x33, 0xfd, 0xf4, 0xae,  0xde, 0x30, 0x07, 0x9b, 0xe5, 0x83, 0x9b, 0x68,
                    0x49, 0xb4, 0x2e, 0x83, 0x1f, 0xc2, 0xb5, 0x7c,  0xa2, 0x19, 0xd8, 0xe5, 0x7c, 0x2f, 0x83, 0xda,
                    0xf7, 0x6b, 0x90, 0xfe, 0xc4, 0x01, 0x5a, 0x97,  0x61, 0xa6, 0x3d, 0x40, 0x0b, 0x58, 0xe6, 0x3d,
            },{
                    0x4d, 0xd1, 0xb2, 0x0f, 0x28, 0xbd, 0xe4, 0x78,  0xf6, 0x4a, 0x0f, 0x93, 0x8b, 0x17, 0xd1, 0xa4,
                    0x3a, 0xec, 0xc9, 0x35, 0x93, 0x56, 0x7e, 0xcb,  0x55, 0x20, 0xa0, 0xfe, 0x6c, 0x89, 0x17, 0x62,
                    0x17, 0x62, 0x4b, 0xb1, 0xb4, 0xde, 0xd1, 0x87,  0xc9, 0x14, 0x3c, 0x4a, 0x7e, 0xa8, 0xe2, 0x7d,
                    0xa0, 0x9f, 0xf6, 0x5c, 0x6a, 0x09, 0x8d, 0xf0,  0x0f, 0xe3, 0x53, 0x25, 0x95, 0x36, 0x28, 0xcb,
            }
    };
 
    size_t i;
    for (i = 0; i < s_table.size(); ++i) {
        tmp.b[i] = (s_table.at(i).at(src->b[i*2+0]) & 0xf0) | (s_table.at(i).at(src->b[i*2+1]) & 0x0f);
    }
 
    *src = tmp;
}

References BIT64::b.

Referenced by roundFunction().

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TP()

void DES::TP

(

BIT64 *

src

)

Transposition (P-BOX).

{
    BIT64 tmp = { { 0 } };
 
    std::vector<uint8_t> tp_table = {
            16,  7, 20, 21,
            29, 12, 28, 17,
            1, 15, 23, 26,
            5, 18, 31, 10,
            2,  8, 24, 14,
            32, 27,  3,  9,
            19, 13, 30,  6,
            22, 11,  4, 25,
    };
 
    size_t i;
    for (i = 0; i < tp_table.size(); ++i) {
        uint8_t j = tp_table.at(i) - 1;
        if (src->b[(j >> 3) + 0] &  mask[j & 7])
            tmp .b[(i >> 3) + 4] |= mask[i & 7];
    }
 
    *src = tmp;
}

References BIT64::b, and mask.

Referenced by roundFunction().

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The documentation for this class was generated from the following files:

• src/Libraries/GRF/DES.hpp
• src/Libraries/GRF/DES.cpp