/*
* 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)
{
if(length == 0 || length >= 56)
throw Invalid_Key_Length("EKSBlowfish", length);
if(workfactor == 0)
throw std::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 std::invalid_argument("Requested Bcrypt work factor too large");
clear();
const byte null_salt[16] = { 0 };
key_expansion(key, length, salt);
const size_t rounds = 1 << workfactor;
for(size_t r = 0; r != rounds; ++r)
{
key_expansion(key, length, null_salt);
key_expansion(salt, 16, null_salt);
}
}
void XTS_Mode::key_schedule(const uint8_t key[], size_t length)
{
const size_t key_half = length / 2;
if(length % 2 == 1 || !m_cipher->valid_keylength(key_half))
throw Invalid_Key_Length(name(), length);
m_cipher->set_key(key, key_half);
m_tweak_cipher->set_key(&key[key_half], key_half);
}
void XTS_Decryption::set_key(const SymmetricKey& key)
{
u32bit key_half = key.length() / 2;
if(key.length() % 2 == 1 || !cipher->valid_keylength(key_half))
throw Invalid_Key_Length(name(), key.length());
cipher->set_key(key.begin(), key_half);
cipher2->set_key(key.begin() + key_half, key_half);
}
/**
* AES Constructor
*/
AES::AES(u32bit key_size) : BlockCipher(16, key_size)
{
if(key_size != 16 && key_size != 24 && key_size != 32)
throw Invalid_Key_Length(name(), key_size);
ROUNDS = (key_size / 4) + 6;
}
