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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/hmac.h>
#include <botan/cbc.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/asn1_obj.h>
#include <botan/oids.h>
#include <algorithm>
#include <memory>
namespace Botan {
/*
* Encrypt some bytes using PBES2
*/
void PBE_PKCS5v20::write(const byte input[], u32bit length)
{
while(length)
{
u32bit put = std::min(DEFAULT_BUFFERSIZE, length);
pipe.write(input, length);
flush_pipe(true);
length -= put;
}
}
/*
* Start encrypting with PBES2
*/
void PBE_PKCS5v20::start_msg()
{
if(direction == ENCRYPTION)
pipe.append(new CBC_Encryption(block_cipher->clone(),
new PKCS7_Padding,
key, iv));
else
pipe.append(new CBC_Decryption(block_cipher->clone(),
new PKCS7_Padding,
key, iv));
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;
SecureVector<byte> buffer(DEFAULT_BUFFERSIZE);
while(pipe.remaining())
{
u32bit got = pipe.read(buffer, buffer.size());
send(buffer, got);
}
}
/*
* Set the passphrase to use
*/
void PBE_PKCS5v20::set_key(const std::string& passphrase)
{
PKCS5_PBKDF2 pbkdf(new HMAC(hash_function->clone()));
key = pbkdf.derive_key(key_length, passphrase,
&salt[0], salt.size(),
iterations).bits_of();
}
/*
* Create a new set of PBES2 parameters
*/
void PBE_PKCS5v20::new_params(RandomNumberGenerator& rng)
{
iterations = 10000;
key_length = block_cipher->MAXIMUM_KEYLENGTH;
salt.resize(12);
rng.randomize(salt, salt.size());
iv.resize(block_cipher->BLOCK_SIZE);
rng.randomize(iv, iv.size());
}
/*
* Encode PKCS#5 PBES2 parameters
*/
MemoryVector<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)
.end_cons()
.get_contents()
)
)
.encode(
AlgorithmIdentifier(block_cipher->name() + "/CBC",
DER_Encoder()
.encode(iv, OCTET_STRING)
.get_contents()
)
)
.end_cons()
.get_contents();
}
/*
* Decode PKCS#5 PBES2 parameters
*/
void PBE_PKCS5v20::decode_params(DataSource& source)
{
AlgorithmIdentifier kdf_algo, enc_algo;
BER_Decoder(source)
.start_cons(SEQUENCE)
.decode(kdf_algo)
.decode(enc_algo)
.verify_end()
.end_cons();
if(kdf_algo.oid == OIDS::lookup("PKCS5.PBKDF2"))
{
BER_Decoder(kdf_algo.parameters)
.start_cons(SEQUENCE)
.decode(salt, OCTET_STRING)
.decode(iterations)
.decode_optional(key_length, INTEGER, UNIVERSAL)
.verify_end()
.end_cons();
}
else
throw Decoding_Error("PBE-PKCS5 v2.0: Unknown KDF algorithm " +
kdf_algo.oid.as_string());
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(!known_cipher(cipher_spec[0]) || 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]);
hash_function = af.make_hash_function("SHA-160");
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");
}
/*
* Return an OID for PBES2
*/
OID PBE_PKCS5v20::get_oid() const
{
return OIDS::lookup("PBE-PKCS5v20");
}
/*
* Check if this is a known PBES2 cipher
*/
bool PBE_PKCS5v20::known_cipher(const std::string& algo)
{
if(algo == "AES-128" || algo == "AES-192" || algo == "AES-256")
return true;
if(algo == "DES" || algo == "TripleDES")
return true;
return false;
}
/*
* PKCS#5 v2.0 PBE Constructor
*/
PBE_PKCS5v20::PBE_PKCS5v20(BlockCipher* cipher,
HashFunction* digest) :
direction(ENCRYPTION), block_cipher(cipher), hash_function(digest)
{
if(!known_cipher(block_cipher->name()))
throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid cipher " + cipher->name());
if(hash_function->name() != "SHA-160")
throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid digest " + digest->name());
}
/*
* PKCS#5 v2.0 PBE Constructor
*/
PBE_PKCS5v20::PBE_PKCS5v20(DataSource& params) : direction(DECRYPTION)
{
hash_function = 0;
block_cipher = 0;
decode_params(params);
}
PBE_PKCS5v20::~PBE_PKCS5v20()
{
delete hash_function;
delete block_cipher;
}
}
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