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/*
* RSA
* (C) 1999-2010,2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/pk_utils.h>
#include <botan/rsa.h>
#include <botan/parsing.h>
#include <botan/keypair.h>
#include <botan/blinding.h>
#include <botan/reducer.h>
#include <future>
#include <iostream>
namespace Botan {
/*
* Create a RSA private key
*/
RSA_PrivateKey::RSA_PrivateKey(RandomNumberGenerator& rng,
size_t bits, size_t exp)
{
if(bits < 1024)
throw Invalid_Argument(algo_name() + ": Can't make a key that is only " +
std::to_string(bits) + " bits long");
if(exp < 3 || exp % 2 == 0)
throw Invalid_Argument(algo_name() + ": Invalid encryption exponent");
e = exp;
do
{
p = random_prime(rng, (bits + 1) / 2, e);
q = random_prime(rng, bits - p.bits(), e);
n = p * q;
} while(n.bits() != bits);
d = inverse_mod(e, lcm(p - 1, q - 1));
d1 = d % (p - 1);
d2 = d % (q - 1);
c = inverse_mod(q, p);
gen_check(rng);
}
/*
* Check Private RSA Parameters
*/
bool RSA_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const
{
if(!IF_Scheme_PrivateKey::check_key(rng, strong))
return false;
if(!strong)
return true;
if((e * d) % lcm(p - 1, q - 1) != 1)
return false;
return KeyPair::signature_consistency_check(rng, *this, "EMSA4(SHA-1)");
}
namespace {
/**
* RSA private (decrypt/sign) operation
*/
class RSA_Private_Operation
{
protected:
size_t get_max_input_bits() const { return (n.bits() - 1); }
RSA_Private_Operation(const RSA_PrivateKey& rsa) :
n(rsa.get_n()),
q(rsa.get_q()),
c(rsa.get_c()),
m_powermod_e_n(rsa.get_e(), rsa.get_n()),
m_powermod_d1_p(rsa.get_d1(), rsa.get_p()),
m_powermod_d2_q(rsa.get_d2(), rsa.get_q()),
m_mod_p(rsa.get_p()),
m_blinder(n,
[this](const BigInt& k) { return m_powermod_e_n(k); },
[this](const BigInt& k) { return inverse_mod(k, n); })
{
}
BigInt blinded_private_op(const BigInt& m) const
{
if(m >= n)
throw Invalid_Argument("RSA private op - input is too large");
return m_blinder.unblind(private_op(m_blinder.blind(m)));
}
BigInt private_op(const BigInt& m) const
{
auto future_j1 = std::async(std::launch::async, m_powermod_d1_p, m);
BigInt j2 = m_powermod_d2_q(m);
BigInt j1 = future_j1.get();
j1 = m_mod_p.reduce(sub_mul(j1, j2, c));
return mul_add(j1, q, j2);
}
const BigInt& n;
const BigInt& q;
const BigInt& c;
Fixed_Exponent_Power_Mod m_powermod_e_n, m_powermod_d1_p, m_powermod_d2_q;
Modular_Reducer m_mod_p;
Blinder m_blinder;
};
class RSA_Signature_Operation : public PK_Ops::Signature_with_EMSA,
private RSA_Private_Operation
{
public:
typedef RSA_PrivateKey Key_Type;
size_t max_input_bits() const override { return get_max_input_bits(); };
RSA_Signature_Operation(const RSA_PrivateKey& rsa, const std::string& emsa) :
PK_Ops::Signature_with_EMSA(emsa),
RSA_Private_Operation(rsa)
{
}
secure_vector<byte> raw_sign(const byte msg[], size_t msg_len,
RandomNumberGenerator&) override
{
const BigInt m(msg, msg_len);
const BigInt x = blinded_private_op(m);
const BigInt c = m_powermod_e_n(x);
BOTAN_ASSERT(m == c, "RSA sign consistency check");
return BigInt::encode_1363(x, n.bytes());
}
};
class RSA_Decryption_Operation : public PK_Ops::Decryption_with_EME,
private RSA_Private_Operation
{
public:
typedef RSA_PrivateKey Key_Type;
size_t max_raw_input_bits() const override { return get_max_input_bits(); };
RSA_Decryption_Operation(const RSA_PrivateKey& rsa, const std::string& eme) :
PK_Ops::Decryption_with_EME(eme),
RSA_Private_Operation(rsa)
{
}
secure_vector<byte> raw_decrypt(const byte msg[], size_t msg_len) override
{
const BigInt m(msg, msg_len);
const BigInt x = blinded_private_op(m);
const BigInt c = m_powermod_e_n(x);
BOTAN_ASSERT(m == c, "RSA decrypt consistency check");
return BigInt::encode_locked(x);
}
};
class RSA_KEM_Decryption_Operation : public PK_Ops::KEM_Decryption_with_KDF,
private RSA_Private_Operation
{
public:
typedef RSA_PrivateKey Key_Type;
RSA_KEM_Decryption_Operation(const RSA_PrivateKey& key,
const std::string& kdf) :
PK_Ops::KEM_Decryption_with_KDF(kdf),
RSA_Private_Operation(key)
{}
secure_vector<byte>
raw_kem_decrypt(const byte encap_key[], size_t len) override
{
const BigInt m(encap_key, len);
const BigInt x = blinded_private_op(m);
const BigInt c = m_powermod_e_n(x);
BOTAN_ASSERT(m == c, "RSA KEM consistency check");
return BigInt::encode_1363(x, n.bytes());
}
};
/**
* RSA public (encrypt/verify) operation
*/
class RSA_Public_Operation
{
public:
RSA_Public_Operation(const RSA_PublicKey& rsa) :
n(rsa.get_n()), powermod_e_n(rsa.get_e(), rsa.get_n())
{}
size_t get_max_input_bits() const { return (n.bits() - 1); }
protected:
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& get_n() const { return n; }
const BigInt& n;
Fixed_Exponent_Power_Mod powermod_e_n;
};
class RSA_Encryption_Operation : public PK_Ops::Encryption_with_EME,
private RSA_Public_Operation
{
public:
typedef RSA_PublicKey Key_Type;
RSA_Encryption_Operation(const RSA_PublicKey& rsa, const std::string& eme) :
PK_Ops::Encryption_with_EME(eme),
RSA_Public_Operation(rsa)
{
}
size_t max_raw_input_bits() const override { return get_max_input_bits(); };
secure_vector<byte> raw_encrypt(const byte msg[], size_t msg_len,
RandomNumberGenerator&) override
{
BigInt m(msg, msg_len);
return BigInt::encode_1363(public_op(m), n.bytes());
}
};
class RSA_Verify_Operation : public PK_Ops::Verification_with_EMSA,
private RSA_Public_Operation
{
public:
typedef RSA_PublicKey Key_Type;
size_t max_input_bits() const override { return get_max_input_bits(); };
RSA_Verify_Operation(const RSA_PublicKey& rsa, const std::string& emsa) :
PK_Ops::Verification_with_EMSA(emsa),
RSA_Public_Operation(rsa)
{
}
bool with_recovery() const override { return true; }
secure_vector<byte> verify_mr(const byte msg[], size_t msg_len) override
{
BigInt m(msg, msg_len);
return BigInt::encode_locked(public_op(m));
}
};
class RSA_KEM_Encryption_Operation : public PK_Ops::KEM_Encryption_with_KDF,
private RSA_Public_Operation
{
public:
typedef RSA_PublicKey Key_Type;
RSA_KEM_Encryption_Operation(const RSA_PublicKey& key,
const std::string& kdf) :
PK_Ops::KEM_Encryption_with_KDF(kdf),
RSA_Public_Operation(key) {}
private:
void raw_kem_encrypt(secure_vector<byte>& out_encapsulated_key,
secure_vector<byte>& raw_shared_key,
Botan::RandomNumberGenerator& rng) override
{
const BigInt r = BigInt::random_integer(rng, 1, get_n());
std::cout << "R = " << r << "\n";
const BigInt c = public_op(r);
std::cout << "C0 = " << c << "\n";
out_encapsulated_key = BigInt::encode_locked(c);
raw_shared_key = BigInt::encode_locked(r);
}
};
BOTAN_REGISTER_PK_ENCRYPTION_OP("RSA", RSA_Encryption_Operation);
BOTAN_REGISTER_PK_DECRYPTION_OP("RSA", RSA_Decryption_Operation);
BOTAN_REGISTER_PK_SIGNATURE_OP("RSA", RSA_Signature_Operation);
BOTAN_REGISTER_PK_VERIFY_OP("RSA", RSA_Verify_Operation);
BOTAN_REGISTER_PK_KEM_ENCRYPTION_OP("RSA", RSA_KEM_Encryption_Operation);
BOTAN_REGISTER_PK_KEM_DECRYPTION_OP("RSA", RSA_KEM_Decryption_Operation);
}
}
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