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/**
* TLS Session Key Source File
* (C) 2004-2006 Jack Lloyd
*
* Released under the terms of the Botan license
*/
#include <botan/tls_session_key.h>
#include <botan/prf_ssl3.h>
#include <botan/prf_tls.h>
#include <botan/lookup.h>
namespace Botan {
/**
* Return the client cipher key
*/
SymmetricKey SessionKeys::client_cipher_key() const
{
return c_cipher;
}
/**
* Return the server cipher key
*/
SymmetricKey SessionKeys::server_cipher_key() const
{
return s_cipher;
}
/**
* Return the client MAC key
*/
SymmetricKey SessionKeys::client_mac_key() const
{
return c_mac;
}
/**
* Return the server MAC key
*/
SymmetricKey SessionKeys::server_mac_key() const
{
return s_mac;
}
/**
* Return the client cipher IV
*/
InitializationVector SessionKeys::client_iv() const
{
return c_iv;
}
/**
* Return the server cipher IV
*/
InitializationVector SessionKeys::server_iv() const
{
return s_iv;
}
/**
* Return the TLS master secret
*/
SecureVector<byte> SessionKeys::master_secret() const
{
return master_sec;
}
/**
* Generate SSLv3 session keys
*/
SymmetricKey SessionKeys::ssl3_keygen(u32bit prf_gen,
const MemoryRegion<byte>& pre_master,
const MemoryRegion<byte>& client_random,
const MemoryRegion<byte>& server_random)
{
SSL3_PRF prf;
SecureVector<byte> salt;
salt.append(client_random);
salt.append(server_random);
master_sec = prf.derive_key(48, pre_master, salt);
salt.destroy();
salt.append(server_random);
salt.append(client_random);
return prf.derive_key(prf_gen, master_sec, salt);
}
/**
* Generate TLS 1.0 session keys
*/
SymmetricKey SessionKeys::tls1_keygen(u32bit prf_gen,
const MemoryRegion<byte>& pre_master,
const MemoryRegion<byte>& client_random,
const MemoryRegion<byte>& server_random)
{
const byte MASTER_SECRET_MAGIC[] = {
0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x73, 0x65, 0x63, 0x72, 0x65,
0x74 };
const byte KEY_GEN_MAGIC[] = {
0x6B, 0x65, 0x79, 0x20, 0x65, 0x78, 0x70, 0x61, 0x6E, 0x73, 0x69, 0x6F,
0x6E };
TLS_PRF prf;
SecureVector<byte> salt;
salt.append(MASTER_SECRET_MAGIC, sizeof(MASTER_SECRET_MAGIC));
salt.append(client_random);
salt.append(server_random);
master_sec = prf.derive_key(48, pre_master, salt);
salt.destroy();
salt.append(KEY_GEN_MAGIC, sizeof(KEY_GEN_MAGIC));
salt.append(server_random);
salt.append(client_random);
return prf.derive_key(prf_gen, master_sec, salt);
}
/**
* SessionKeys Constructor
*/
SessionKeys::SessionKeys(const CipherSuite& suite, Version_Code version,
const MemoryRegion<byte>& pre_master_secret,
const MemoryRegion<byte>& c_random,
const MemoryRegion<byte>& s_random)
{
if(version != SSL_V3 && version != TLS_V10)
throw Invalid_Argument("SessionKeys: Unknown version code");
const u32bit mac_keylen = output_length_of(suite.mac_algo());
u32bit cipher_keylen = suite.cipher_keylen();
u32bit cipher_ivlen = 0;
if(have_block_cipher(suite.cipher_algo()))
cipher_ivlen = block_size_of(suite.cipher_algo());
const u32bit prf_gen = 2 * (mac_keylen + cipher_keylen + cipher_ivlen);
SymmetricKey keyblock = (version == SSL_V3) ?
ssl3_keygen(prf_gen, pre_master_secret, c_random, s_random) :
tls1_keygen(prf_gen, pre_master_secret, c_random, s_random);
const byte* key_data = keyblock.begin();
c_mac = SymmetricKey(key_data, mac_keylen);
key_data += mac_keylen;
s_mac = SymmetricKey(key_data, mac_keylen);
key_data += mac_keylen;
c_cipher = SymmetricKey(key_data, cipher_keylen);
key_data += cipher_keylen;
s_cipher = SymmetricKey(key_data, cipher_keylen);
key_data += cipher_keylen;
c_iv = InitializationVector(key_data, cipher_ivlen);
key_data += cipher_ivlen;
s_iv = InitializationVector(key_data, cipher_ivlen);
}
}
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