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/*
* PKCS #5 PBES2
* (C) 1999-2008 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/pbes2.h>
#include <botan/pbkdf2.h>
#include <botan/algo_factory.h>
#include <botan/libstate.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/parsing.h>
#include <botan/alg_id.h>
#include <botan/oids.h>
#include <botan/lookup.h>
#include <algorithm>
namespace Botan {
/*
* Encrypt some bytes using PBES2
*/
void PBE_PKCS5v20::write(const byte input[], size_t length)
{
pipe.write(input, length);
flush_pipe(true);
}
/*
* Start encrypting with PBES2
*/
void PBE_PKCS5v20::start_msg()
{
pipe.append(get_cipher(block_cipher->name() + "/CBC/PKCS7",
key, iv, direction));
pipe.start_msg();
if(pipe.message_count() > 1)
pipe.set_default_msg(pipe.default_msg() + 1);
}
/*
* Finish encrypting with PBES2
*/
void PBE_PKCS5v20::end_msg()
{
pipe.end_msg();
flush_pipe(false);
pipe.reset();
}
/*
* Flush the pipe
*/
void PBE_PKCS5v20::flush_pipe(bool safe_to_skip)
{
if(safe_to_skip && pipe.remaining() < 64)
return;
secure_vector<byte> buffer(DEFAULT_BUFFERSIZE);
while(pipe.remaining())
{
const size_t got = pipe.read(&buffer[0], buffer.size());
send(buffer, got);
}
}
/*
* Encode PKCS#5 PBES2 parameters
*/
std::vector<byte> PBE_PKCS5v20::encode_params() const
{
return DER_Encoder()
.start_cons(SEQUENCE)
.encode(
AlgorithmIdentifier("PKCS5.PBKDF2",
DER_Encoder()
.start_cons(SEQUENCE)
.encode(salt, OCTET_STRING)
.encode(iterations)
.encode(key_length)
.encode_if(
m_prf->name() != "HMAC(SHA-160)",
AlgorithmIdentifier(m_prf->name(),
AlgorithmIdentifier::USE_NULL_PARAM))
.end_cons()
.get_contents_unlocked()
)
)
.encode(
AlgorithmIdentifier(block_cipher->name() + "/CBC",
DER_Encoder().encode(iv, OCTET_STRING).get_contents_unlocked()
)
)
.end_cons()
.get_contents_unlocked();
}
/*
* Return an OID for PBES2
*/
OID PBE_PKCS5v20::get_oid() const
{
return OIDS::lookup("PBE-PKCS5v20");
}
std::string PBE_PKCS5v20::name() const
{
return "PBE-PKCS5v20(" + block_cipher->name() + "," +
m_prf->name() + ")";
}
/*
* PKCS#5 v2.0 PBE Constructor
*/
PBE_PKCS5v20::PBE_PKCS5v20(BlockCipher* cipher,
MessageAuthenticationCode* mac,
const std::string& passphrase,
std::chrono::milliseconds msec,
RandomNumberGenerator& rng) :
direction(ENCRYPTION),
block_cipher(cipher),
m_prf(mac),
salt(rng.random_vec(12)),
iv(rng.random_vec(block_cipher->block_size())),
iterations(0),
key_length(block_cipher->maximum_keylength())
{
PKCS5_PBKDF2 pbkdf(m_prf->clone());
key = pbkdf.derive_key(key_length, passphrase,
&salt[0], salt.size(),
msec, iterations).bits_of();
}
/*
* PKCS#5 v2.0 PBE Constructor
*/
PBE_PKCS5v20::PBE_PKCS5v20(const std::vector<byte>& params,
const std::string& passphrase) :
direction(DECRYPTION),
block_cipher(nullptr),
m_prf(nullptr)
{
AlgorithmIdentifier kdf_algo, enc_algo;
BER_Decoder(params)
.start_cons(SEQUENCE)
.decode(kdf_algo)
.decode(enc_algo)
.verify_end()
.end_cons();
AlgorithmIdentifier prf_algo;
if(kdf_algo.oid != OIDS::lookup("PKCS5.PBKDF2"))
throw Decoding_Error("PBE-PKCS5 v2.0: Unknown KDF algorithm " +
kdf_algo.oid.as_string());
BER_Decoder(kdf_algo.parameters)
.start_cons(SEQUENCE)
.decode(salt, OCTET_STRING)
.decode(iterations)
.decode_optional(key_length, INTEGER, UNIVERSAL)
.decode_optional(prf_algo, SEQUENCE, CONSTRUCTED,
AlgorithmIdentifier("HMAC(SHA-160)",
AlgorithmIdentifier::USE_NULL_PARAM))
.verify_end()
.end_cons();
Algorithm_Factory& af = global_state().algorithm_factory();
std::string cipher = OIDS::lookup(enc_algo.oid);
std::vector<std::string> cipher_spec = split_on(cipher, '/');
if(cipher_spec.size() != 2)
throw Decoding_Error("PBE-PKCS5 v2.0: Invalid cipher spec " + cipher);
if(cipher_spec[1] != "CBC")
throw Decoding_Error("PBE-PKCS5 v2.0: Don't know param format for " +
cipher);
BER_Decoder(enc_algo.parameters).decode(iv, OCTET_STRING).verify_end();
block_cipher = af.make_block_cipher(cipher_spec[0]);
m_prf = af.make_mac(OIDS::lookup(prf_algo.oid));
if(key_length == 0)
key_length = block_cipher->maximum_keylength();
if(salt.size() < 8)
throw Decoding_Error("PBE-PKCS5 v2.0: Encoded salt is too small");
PKCS5_PBKDF2 pbkdf(m_prf->clone());
key = pbkdf.derive_key(key_length, passphrase,
&salt[0], salt.size(),
iterations).bits_of();
}
PBE_PKCS5v20::~PBE_PKCS5v20()
{
delete m_prf;
delete block_cipher;
}
}
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