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/*************************************************
* Blowfish Source File *
* (C) 1999-2007 The Botan Project *
*************************************************/
#include <botan/blowfish.h>
#include <botan/loadstor.h>
namespace Botan {
/*************************************************
* Blowfish Encryption *
*************************************************/
void Blowfish::enc(const byte in[], byte out[]) const
{
u32bit L = load_be<u32bit>(in, 0);
u32bit R = load_be<u32bit>(in, 1);
for(u32bit j = 0; j != 16; j += 2)
{
L ^= P[j];
R ^= ((S1[get_byte(0, L)] + S2[get_byte(1, L)]) ^
S3[get_byte(2, L)]) + S4[get_byte(3, L)];
R ^= P[j+1];
L ^= ((S1[get_byte(0, R)] + S2[get_byte(1, R)]) ^
S3[get_byte(2, R)]) + S4[get_byte(3, R)];
}
L ^= P[16]; R ^= P[17];
store_be(out, R, L);
}
/*************************************************
* Blowfish Decryption *
*************************************************/
void Blowfish::dec(const byte in[], byte out[]) const
{
u32bit L = load_be<u32bit>(in, 0);
u32bit R = load_be<u32bit>(in, 1);
for(u32bit j = 17; j != 1; j -= 2)
{
L ^= P[j];
R ^= ((S1[get_byte(0, L)] + S2[get_byte(1, L)]) ^
S3[get_byte(2, L)]) + S4[get_byte(3, L)];
R ^= P[j-1];
L ^= ((S1[get_byte(0, R)] + S2[get_byte(1, R)]) ^
S3[get_byte(2, R)]) + S4[get_byte(3, R)];
}
L ^= P[1]; R ^= P[0];
store_be(out, R, L);
}
/*************************************************
* Blowfish Key Schedule *
*************************************************/
void Blowfish::key(const byte key[], u32bit length)
{
clear();
for(u32bit j = 0, k = 0; j != 18; ++j, k += 4)
P[j] ^= make_u32bit(key[(k ) % length], key[(k+1) % length],
key[(k+2) % length], key[(k+3) % length]);
u32bit L = 0, R = 0;
generate_sbox(P, 18, L, R);
generate_sbox(S1, 256, L, R);
generate_sbox(S2, 256, L, R);
generate_sbox(S3, 256, L, R);
generate_sbox(S4, 256, L, R);
}
/*************************************************
* Generate one of the Sboxes *
*************************************************/
void Blowfish::generate_sbox(u32bit Box[], u32bit size,
u32bit& L, u32bit& R) const
{
for(u32bit j = 0; j != size; j += 2)
{
for(u32bit k = 0; k != 16; k += 2)
{
L ^= P[k];
R ^= ((S1[get_byte(0, L)] + S2[get_byte(1, L)]) ^
S3[get_byte(2, L)]) + S4[get_byte(3, L)];
R ^= P[k+1];
L ^= ((S1[get_byte(0, R)] + S2[get_byte(1, R)]) ^
S3[get_byte(2, R)]) + S4[get_byte(3, R)];
}
u32bit T = R; R = L ^ P[16]; L = T ^ P[17];
Box[j] = L; Box[j+1] = R;
}
}
/*************************************************
* Clear memory of sensitive data *
*************************************************/
void Blowfish::clear() throw()
{
P.copy(PBOX, 18);
S1.copy(SBOX + 0, 256);
S2.copy(SBOX + 256, 256);
S3.copy(SBOX + 512, 256);
S4.copy(SBOX + 768, 256);
}
}
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