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/*************************************************
* PKCS #5 PBES2 Source File *
* (C) 1999-2008 The Botan Project *
*************************************************/
#include <botan/pbe_pkcs.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/parsing.h>
#include <botan/lookup.h>
#include <botan/rng.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()
{
pipe.append(get_cipher(cipher, 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;
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)
{
std::auto_ptr<S2K> pbkdf(get_s2k("PBKDF2(" + digest + ")"));
pbkdf->set_iterations(iterations);
pbkdf->change_salt(salt, salt.size());
key = pbkdf->derive_key(key_length, passphrase).bits_of();
}
/*************************************************
* Create a new set of PBES2 parameters *
*************************************************/
void PBE_PKCS5v20::new_params()
{
iterations = 2048;
key_length = max_keylength_of(cipher_algo);
salt.create(8);
iv.create(block_size_of(cipher_algo));
Global_RNG::randomize(salt, salt.size());
Global_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(cipher,
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"))
{
digest = "SHA-160";
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());
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);
cipher_algo = deref_alias(cipher_spec[0]);
if(!known_cipher(cipher_algo) || 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();
if(key_length == 0)
key_length = max_keylength_of(cipher_algo);
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) const
{
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(const std::string& d_algo,
const std::string& c_algo) :
direction(ENCRYPTION), digest(deref_alias(d_algo)), cipher(c_algo)
{
std::vector<std::string> cipher_spec = split_on(cipher, '/');
if(cipher_spec.size() != 2)
throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid cipher spec " + cipher);
cipher_algo = deref_alias(cipher_spec[0]);
const std::string cipher_mode = cipher_spec[1];
if(!have_block_cipher(cipher_algo))
throw Algorithm_Not_Found(cipher_algo);
if(!have_hash(digest))
throw Algorithm_Not_Found(digest);
if(!known_cipher(cipher_algo))
throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid cipher " + cipher);
if(cipher_mode != "CBC")
throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid cipher " + cipher);
if(digest != "SHA-160")
throw Invalid_Argument("PBE-PKCS5 v2.0: Invalid digest " + digest);
}
/*************************************************
* PKCS#5 v2.0 PBE Constructor *
*************************************************/
PBE_PKCS5v20::PBE_PKCS5v20(DataSource& params) : direction(DECRYPTION)
{
decode_params(params);
}
}
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