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/*
* Blowfish
* (C) 1999-2011 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/blowfish.h>
#include <botan/loadstor.h>
namespace Botan {
/*
* Blowfish Encryption
*/
void Blowfish::encrypt_n(const byte in[], byte out[], size_t blocks) const
{
const u32bit* S1 = &S[0];
const u32bit* S2 = &S[256];
const u32bit* S3 = &S[512];
const u32bit* S4 = &S[768];
for(size_t i = 0; i != blocks; ++i)
{
u32bit L = load_be<u32bit>(in, 0);
u32bit R = load_be<u32bit>(in, 1);
for(size_t 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);
in += BLOCK_SIZE;
out += BLOCK_SIZE;
}
}
/*
* Blowfish Decryption
*/
void Blowfish::decrypt_n(const byte in[], byte out[], size_t blocks) const
{
const u32bit* S1 = &S[0];
const u32bit* S2 = &S[256];
const u32bit* S3 = &S[512];
const u32bit* S4 = &S[768];
for(size_t i = 0; i != blocks; ++i)
{
u32bit L = load_be<u32bit>(in, 0);
u32bit R = load_be<u32bit>(in, 1);
for(size_t 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);
in += BLOCK_SIZE;
out += BLOCK_SIZE;
}
}
/*
* Blowfish Key Schedule
*/
void Blowfish::key_schedule(const byte key[], size_t length)
{
P.resize(18);
copy_mem(P.data(), P_INIT, 18);
S.resize(1024);
copy_mem(S.data(), S_INIT, 1024);
const byte null_salt[16] = { 0 };
key_expansion(key, length, null_salt);
}
void Blowfish::key_expansion(const byte key[],
size_t length,
const byte salt[16])
{
for(size_t i = 0, j = 0; i != 18; ++i, j += 4)
P[i] ^= make_u32bit(key[(j ) % length], key[(j+1) % length],
key[(j+2) % length], key[(j+3) % length]);
u32bit L = 0, R = 0;
generate_sbox(P, L, R, salt, 0);
generate_sbox(S, L, R, salt, 2);
}
/*
* Modified key schedule used for bcrypt password hashing
*/
void Blowfish::eks_key_schedule(const byte key[], size_t length,
const byte salt[16], size_t workfactor)
{
// Truncate longer passwords to the 56 byte limit Blowfish enforces
length = std::min<size_t>(length, 55);
if(workfactor == 0)
throw Invalid_Argument("Bcrypt work factor must be at least 1");
/*
* On a 2.8 GHz Core-i7, workfactor == 18 takes about 25 seconds to
* hash a password. This seems like a reasonable upper bound for the
* time being.
*/
if(workfactor > 18)
throw Invalid_Argument("Requested Bcrypt work factor " +
std::to_string(workfactor) + " too large");
P.resize(18);
copy_mem(P.data(), P_INIT, 18);
S.resize(1024);
copy_mem(S.data(), S_INIT, 1024);
key_expansion(key, length, salt);
const byte null_salt[16] = { 0 };
const size_t rounds = static_cast<size_t>(1) << workfactor;
for(size_t r = 0; r != rounds; ++r)
{
key_expansion(key, length, null_salt);
key_expansion(salt, 16, null_salt);
}
}
/*
* Generate one of the Sboxes
*/
void Blowfish::generate_sbox(secure_vector<u32bit>& box,
u32bit& L, u32bit& R,
const byte salt[16],
size_t salt_off) const
{
const u32bit* S1 = &S[0];
const u32bit* S2 = &S[256];
const u32bit* S3 = &S[512];
const u32bit* S4 = &S[768];
for(size_t i = 0; i != box.size(); i += 2)
{
L ^= load_be<u32bit>(salt, (i + salt_off) % 4);
R ^= load_be<u32bit>(salt, (i + salt_off + 1) % 4);
for(size_t 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)];
}
u32bit T = R; R = L ^ P[16]; L = T ^ P[17];
box[i] = L;
box[i+1] = R;
}
}
/*
* Clear memory of sensitive data
*/
void Blowfish::clear()
{
zap(P);
zap(S);
}
}
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