/*
* Set the EAX key
*/
void EAX_Base::set_key(const SymmetricKey& key)
{
/*
* These could share the key schedule, which is one nice part of EAX,
* but it's much easier to ignore that here...
*/
ctr->set_key(key);
cmac->set_key(key);
header_mac = eax_prf(1, BLOCK_SIZE, cmac, 0, 0);
}
/*
* Set the EAX key
*/
void EAX_Mode::key_schedule(const byte key[], size_t length)
{
/*
* These could share the key schedule, which is one nice part of EAX,
* but it's much easier to ignore that here...
*/
m_ctr->set_key(key, length);
m_cmac->set_key(key, length);
m_ad_mac = eax_prf(1, block_size(), *m_cmac, nullptr, 0);
}
secure_vector<byte> EAX_Mode::start_raw(const byte nonce[], size_t nonce_len)
{
if(!valid_nonce_length(nonce_len))
throw Invalid_IV_Length(name(), nonce_len);
m_nonce_mac = eax_prf(0, block_size(), *m_cmac, nonce, nonce_len);
m_ctr->set_iv(m_nonce_mac.data(), m_nonce_mac.size());
for(size_t i = 0; i != block_size() - 1; ++i)
m_cmac->update(0);
m_cmac->update(2);
return secure_vector<byte>();
}
/*
* Set the EAX header
*/
void EAX_Base::set_header(const byte header[], size_t length)
{
header_mac = eax_prf(1, BLOCK_SIZE, cmac, header, length);
}
/*
* Set the EAX nonce
*/
void EAX_Base::set_iv(const InitializationVector& iv)
{
nonce_mac = eax_prf(0, BLOCK_SIZE, cmac, iv.begin(), iv.length());
ctr->set_iv(&nonce_mac[0], nonce_mac.size());
}
/*
* Set the EAX associated data
*/
void EAX_Mode::set_associated_data(const byte ad[], size_t length)
{
m_ad_mac = eax_prf(1, block_size(), *m_cmac, ad, length);
}
