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/*
* RSA
* (C) 1999-2008 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_RSA_H__
#define BOTAN_RSA_H__
#include <botan/if_algo.h>
#include <botan/pk_ops.h>
#include <botan/reducer.h>
#include <botan/blinding.h>
namespace Botan {
/**
* RSA Public Key
*/
class BOTAN_DLL RSA_PublicKey : public virtual IF_Scheme_PublicKey
{
public:
std::string algo_name() const { return "RSA"; }
RSA_PublicKey(const AlgorithmIdentifier& alg_id,
const secure_vector<byte>& key_bits) :
IF_Scheme_PublicKey(alg_id, key_bits)
{}
/**
* Create a RSA_PublicKey
* @arg n the modulus
* @arg e the exponent
*/
RSA_PublicKey(const BigInt& n, const BigInt& e) :
IF_Scheme_PublicKey(n, e)
{}
protected:
RSA_PublicKey() {}
};
/**
* RSA Private Key
*/
class BOTAN_DLL RSA_PrivateKey : public RSA_PublicKey,
public IF_Scheme_PrivateKey
{
public:
bool check_key(RandomNumberGenerator& rng, bool) const;
RSA_PrivateKey(const AlgorithmIdentifier& alg_id,
const secure_vector<byte>& key_bits,
RandomNumberGenerator& rng) :
IF_Scheme_PrivateKey(rng, alg_id, key_bits) {}
/**
* Construct a private key from the specified parameters.
* @param rng a random number generator
* @param p the first prime
* @param q the second prime
* @param e the exponent
* @param d if specified, this has to be d with
* exp * d = 1 mod (p - 1, q - 1). Leave it as 0 if you wish to
* the constructor to calculate it.
* @param n if specified, this must be n = p * q. Leave it as 0
* if you wish to the constructor to calculate it.
*/
RSA_PrivateKey(RandomNumberGenerator& rng,
const BigInt& p, const BigInt& q,
const BigInt& e, const BigInt& d = 0,
const BigInt& n = 0) :
IF_Scheme_PrivateKey(rng, p, q, e, d, n) {}
/**
* Create a new private key with the specified bit length
* @param rng the random number generator to use
* @param bits the desired bit length of the private key
* @param exp the public exponent to be used
*/
RSA_PrivateKey(RandomNumberGenerator& rng,
size_t bits, size_t exp = 65537);
};
/**
* RSA private (decrypt/sign) operation
*/
class BOTAN_DLL RSA_Private_Operation : public PK_Ops::Signature,
public PK_Ops::Decryption
{
public:
RSA_Private_Operation(const RSA_PrivateKey& rsa,
RandomNumberGenerator& rng);
size_t max_input_bits() const { return (n.bits() - 1); }
secure_vector<byte> sign(const byte msg[], size_t msg_len,
RandomNumberGenerator& rng);
secure_vector<byte> decrypt(const byte msg[], size_t msg_len);
private:
BigInt private_op(const BigInt& m) const;
const BigInt& n;
const BigInt& q;
const BigInt& c;
Fixed_Exponent_Power_Mod powermod_e_n, powermod_d1_p, powermod_d2_q;
Modular_Reducer mod_p;
Blinder blinder;
};
/**
* RSA public (encrypt/verify) operation
*/
class BOTAN_DLL RSA_Public_Operation : public PK_Ops::Verification,
public PK_Ops::Encryption
{
public:
RSA_Public_Operation(const RSA_PublicKey& rsa) :
n(rsa.get_n()), powermod_e_n(rsa.get_e(), rsa.get_n())
{}
size_t max_input_bits() const { return (n.bits() - 1); }
bool with_recovery() const { return true; }
secure_vector<byte> encrypt(const byte msg[], size_t msg_len,
RandomNumberGenerator&)
{
BigInt m(msg, msg_len);
return BigInt::encode_1363(public_op(m), n.bytes());
}
secure_vector<byte> verify_mr(const byte msg[], size_t msg_len)
{
BigInt m(msg, msg_len);
return BigInt::encode_locked(public_op(m));
}
private:
BigInt public_op(const BigInt& m) const
{
if(m >= n)
throw Invalid_Argument("RSA public op - input is too large");
return powermod_e_n(m);
}
const BigInt& n;
Fixed_Exponent_Power_Mod powermod_e_n;
};
}
#endif
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