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/*************************************************
* OpenSSL ARC4 Source File *
* (C) 1999-2007 The Botan Project *
*************************************************/
#include <botan/eng_ossl.h>
#include <botan/lookup.h>
#include <botan/parsing.h>
#include <openssl/rc4.h>
namespace Botan {
namespace {
/*************************************************
* OpenSSL ARC4 *
*************************************************/
class OpenSSL_ARC4 : public StreamCipher
{
public:
void clear() throw() { std::memset(&state, 0, sizeof(state)); }
std::string name() const;
StreamCipher* clone() const { return new OpenSSL_ARC4(SKIP); }
OpenSSL_ARC4(u32bit s = 0) : StreamCipher(1, 32), SKIP(s) { clear(); }
~OpenSSL_ARC4() { clear(); }
private:
void cipher(const byte[], byte[], u32bit);
void key(const byte[], u32bit);
const u32bit SKIP;
RC4_KEY state;
};
/*************************************************
* Return the name of this type *
*************************************************/
std::string OpenSSL_ARC4::name() const
{
if(SKIP == 0) return "ARC4";
if(SKIP == 256) return "MARK-4";
else return "RC4_skip(" + to_string(SKIP) + ")";
}
/*************************************************
* ARC4 Key Schedule *
*************************************************/
void OpenSSL_ARC4::key(const byte key[], u32bit length)
{
RC4_set_key(&state, length, key);
byte dummy = 0;
for(u32bit j = 0; j != SKIP; j++)
RC4(&state, 1, &dummy, &dummy);
}
/*************************************************
* ARC4 Encryption *
*************************************************/
void OpenSSL_ARC4::cipher(const byte in[], byte out[], u32bit length)
{
RC4(&state, length, in, out);
}
}
/*************************************************
* Look for an algorithm with this name *
*************************************************/
StreamCipher*
OpenSSL_Engine::find_stream_cipher(const std::string& algo_spec) const
{
std::vector<std::string> name = parse_algorithm_name(algo_spec);
if(name.size() == 0)
return 0;
const std::string algo_name = deref_alias(name[0]);
#define HANDLE_TYPE_ONE_U32BIT(NAME, TYPE, DEFAULT) \
if(algo_name == NAME) \
{ \
if(name.size() == 1) \
return new TYPE(DEFAULT); \
if(name.size() == 2) \
return new TYPE(to_u32bit(name[1])); \
throw Invalid_Algorithm_Name(algo_spec); \
}
HANDLE_TYPE_ONE_U32BIT("ARC4", OpenSSL_ARC4, 0);
HANDLE_TYPE_ONE_U32BIT("RC4_drop", OpenSSL_ARC4, 768);
return 0;
}
}
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