Botan 1.10.17
Botan::ElGamal_PrivateKey Class Reference

#include <elgamal.h>

Inheritance diagram for Botan::ElGamal_PrivateKey:
Botan::ElGamal_PublicKey Botan::DL_Scheme_PrivateKey Botan::DL_Scheme_PublicKey Botan::DL_Scheme_PublicKey Botan::Private_Key Botan::Public_Key Botan::Public_Key Botan::Public_Key

Public Member Functions

std::string algo_name () const
AlgorithmIdentifier algorithm_identifier () const
bool check_key (RandomNumberGenerator &rng, bool) const
 ElGamal_PrivateKey (const AlgorithmIdentifier &alg_id, const MemoryRegion< byte > &key_bits, RandomNumberGenerator &rng)
 ElGamal_PrivateKey (RandomNumberGenerator &rng, const DL_Group &group, const BigInt &priv_key=0)
const DL_Groupget_domain () const
virtual OID get_oid () const
const BigIntget_x () const
const BigIntget_y () const
DL_Group::Format group_format () const
const BigIntgroup_g () const
const BigIntgroup_p () const
const BigIntgroup_q () const
size_t max_input_bits () const
virtual size_t message_part_size () const
virtual size_t message_parts () const
virtual AlgorithmIdentifier pkcs8_algorithm_identifier () const
MemoryVector< bytepkcs8_private_key () const
MemoryVector< bytex509_subject_public_key () const

Protected Member Functions

void gen_check (RandomNumberGenerator &rng) const
void load_check (RandomNumberGenerator &rng) const
virtual void load_check (RandomNumberGenerator &rng) const

Protected Attributes

DL_Group group
BigInt x
BigInt y

Detailed Description

ElGamal Private Key

Definition at line 43 of file elgamal.h.

Constructor & Destructor Documentation

◆ ElGamal_PrivateKey() [1/2]

Botan::ElGamal_PrivateKey::ElGamal_PrivateKey ( const AlgorithmIdentifier & alg_id,
const MemoryRegion< byte > & key_bits,
RandomNumberGenerator & rng )

Definition at line 46 of file elgamal.cpp.

48 :
50 {
51 y = power_mod(group_g(), x, group_p());
52 load_check(rng);
53 }
const BigInt & group_p() const
Definition dl_algo.h:44
const BigInt & group_g() const
Definition dl_algo.h:56
virtual void load_check(RandomNumberGenerator &rng) const
Definition pk_keys.cpp:31
BigInt power_mod(const BigInt &base, const BigInt &exp, const BigInt &mod)
Definition numthry.cpp:366

References Botan::DL_Scheme_PrivateKey::DL_Scheme_PrivateKey(), Botan::DL_Scheme_PublicKey::group_g(), Botan::DL_Scheme_PublicKey::group_p(), Botan::Private_Key::load_check(), Botan::power_mod(), Botan::DL_Scheme_PrivateKey::x, and Botan::DL_Scheme_PublicKey::y.

Referenced by Botan::make_private_key().

◆ ElGamal_PrivateKey() [2/2]

Botan::ElGamal_PrivateKey::ElGamal_PrivateKey ( RandomNumberGenerator & rng,
const DL_Group & group,
const BigInt & priv_key = 0 )

Definition at line 28 of file elgamal.cpp.

31 {
32 group = grp;
33 x = x_arg;
34
35 if(x == 0)
36 x.randomize(rng, 2 * dl_work_factor(group_p().bits()));
37
38 y = power_mod(group_g(), x, group_p());
39
40 if(x_arg == 0)
41 gen_check(rng);
42 else
43 load_check(rng);
44 }
void randomize(RandomNumberGenerator &rng, size_t bitsize=0)
Definition big_rand.cpp:29
void gen_check(RandomNumberGenerator &rng) const
Definition pk_keys.cpp:49
size_t dl_work_factor(size_t bits)

References Botan::dl_work_factor(), Botan::Private_Key::gen_check(), Botan::DL_Scheme_PublicKey::group, Botan::DL_Scheme_PublicKey::group_g(), Botan::DL_Scheme_PublicKey::group_p(), Botan::Private_Key::load_check(), Botan::power_mod(), Botan::BigInt::randomize(), Botan::DL_Scheme_PrivateKey::x, and Botan::DL_Scheme_PublicKey::y.

Member Function Documentation

◆ algo_name()

std::string Botan::ElGamal_PublicKey::algo_name ( ) const
inlinevirtualinherited

Get the name of the underlying public key scheme.

Returns
name of the public key scheme

Implements Botan::Public_Key.

Definition at line 25 of file elgamal.h.

25{ return "ElGamal"; }

◆ algorithm_identifier()

AlgorithmIdentifier Botan::DL_Scheme_PublicKey::algorithm_identifier ( ) const
virtualinherited
Returns
X.509 AlgorithmIdentifier for this key

Implements Botan::Public_Key.

Definition at line 15 of file dl_algo.cpp.

16 {
19 }
SecureVector< byte > DER_encode(Format format) const
Definition dl_group.cpp:205
virtual DL_Group::Format group_format() const =0
virtual OID get_oid() const
Definition pk_keys.cpp:17

References Botan::AlgorithmIdentifier::AlgorithmIdentifier(), Botan::DL_Group::DER_encode(), Botan::Public_Key::get_oid(), group, and group_format().

◆ check_key()

bool Botan::ElGamal_PrivateKey::check_key ( RandomNumberGenerator & rng,
bool strong ) const
virtual

Test the key values for consistency.

Parameters
rngrng to use
strongwhether to perform strong and lengthy version of the test
Returns
true if the test is passed

Reimplemented from Botan::DL_Scheme_PublicKey.

Definition at line 58 of file elgamal.cpp.

60 {
61 if(!DL_Scheme_PrivateKey::check_key(rng, strong))
62 return false;
63
64 if(!strong)
65 return true;
66
67 return KeyPair::encryption_consistency_check(rng, *this, "EME1(SHA-1)");
68 }
bool check_key(RandomNumberGenerator &rng, bool) const
Definition dl_algo.cpp:67
bool encryption_consistency_check(RandomNumberGenerator &rng, const Private_Key &key, const std::string &padding)
Definition keypair.cpp:18

References Botan::DL_Scheme_PrivateKey::check_key(), and Botan::KeyPair::encryption_consistency_check().

◆ gen_check()

void Botan::Private_Key::gen_check ( RandomNumberGenerator & rng) const
protectedinherited

Self-test after generating a key

Parameters
rnga random number generator

Definition at line 49 of file pk_keys.cpp.

50 {
51 if(!check_key(rng, BOTAN_PRIVATE_KEY_STRONG_CHECKS_ON_GENERATE))
52 throw Self_Test_Failure(algo_name() + " private key generation failed");
53 }
virtual bool check_key(RandomNumberGenerator &rng, bool strong) const =0
virtual std::string algo_name() const =0
Self_Test_Failure(const std::string &err)
Definition exceptn.h:177

References Botan::Public_Key::algo_name(), Botan::Public_Key::check_key(), and Botan::Self_Test_Failure::Self_Test_Failure().

Referenced by Botan::DH_PrivateKey::DH_PrivateKey(), Botan::DSA_PrivateKey::DSA_PrivateKey(), Botan::ElGamal_PrivateKey::ElGamal_PrivateKey(), Botan::NR_PrivateKey::NR_PrivateKey(), Botan::RSA_PrivateKey::RSA_PrivateKey(), and Botan::RW_PrivateKey::RW_PrivateKey().

◆ get_domain()

const DL_Group & Botan::DL_Scheme_PublicKey::get_domain ( ) const
inlineinherited

Get the DL domain parameters of this key.

Returns
DL domain parameters of this key

Definition at line 33 of file dl_algo.h.

33{ return group; }

References group.

Referenced by Botan::Server_Key_Exchange::Server_Key_Exchange().

◆ get_oid()

OID Botan::Public_Key::get_oid ( ) const
virtualinherited

Get the OID of the underlying public key scheme.

Returns
OID of the public key scheme

Definition at line 17 of file pk_keys.cpp.

18 {
19 try {
20 return OIDS::lookup(algo_name());
21 }
22 catch(Lookup_Error)
23 {
24 throw Lookup_Error("PK algo " + algo_name() + " has no defined OIDs");
25 }
26 }
std::string lookup(const OID &oid)
Definition oids.cpp:31
Lookup_Error(const std::string &err)
Definition exceptn.h:37

References algo_name(), Botan::OIDS::lookup(), and Botan::Lookup_Error::Lookup_Error().

Referenced by algo_name(), Botan::DL_Scheme_PublicKey::algorithm_identifier(), Botan::EC_PublicKey::algorithm_identifier(), and Botan::IF_Scheme_PublicKey::algorithm_identifier().

◆ get_x()

const BigInt & Botan::DL_Scheme_PrivateKey::get_x ( ) const
inlineinherited

Get the secret key x.

Returns
secret key

Definition at line 95 of file dl_algo.h.

95{ return x; }

References x.

Referenced by Botan::ElGamal_Decryption_Operation::ElGamal_Decryption_Operation().

◆ get_y()

const BigInt & Botan::DL_Scheme_PublicKey::get_y ( ) const
inlineinherited

Get the public value y with y = g^x mod p where x is the secret key.

Definition at line 38 of file dl_algo.h.

38{ return y; }

References y.

Referenced by Botan::ElGamal_Encryption_Operation::ElGamal_Encryption_Operation().

◆ group_format()

DL_Group::Format Botan::ElGamal_PublicKey::group_format ( ) const
inlinevirtualinherited

Get the underlying groups encoding format.

Returns
encoding format

Implements Botan::DL_Scheme_PublicKey.

Definition at line 26 of file elgamal.h.

26{ return DL_Group::ANSI_X9_42; }

References Botan::DL_Group::ANSI_X9_42.

◆ group_g()

◆ group_p()

◆ group_q()

◆ load_check() [1/2]

void Botan::Private_Key::load_check ( RandomNumberGenerator & rng) const
protectedvirtualinherited

◆ load_check() [2/2]

void Botan::Public_Key::load_check ( RandomNumberGenerator & rng) const
protectedvirtualinherited

Self-test after loading a key

Parameters
rnga random number generator

Reimplemented in Botan::Private_Key.

Definition at line 31 of file pk_keys.cpp.

32 {
33 if(!check_key(rng, BOTAN_PUBLIC_KEY_STRONG_CHECKS_ON_LOAD))
34 throw Invalid_Argument(algo_name() + ": Invalid public key");
35 }

References algo_name(), and check_key().

◆ max_input_bits()

size_t Botan::ElGamal_PublicKey::max_input_bits ( ) const
inlinevirtualinherited

Get the maximum message size in bits supported by this public key.

Returns
maximum message size in bits

Implements Botan::Public_Key.

Definition at line 28 of file elgamal.h.

28{ return (group_p().bits() - 1); }

References Botan::DL_Scheme_PublicKey::group_p().

◆ message_part_size()

virtual size_t Botan::Public_Key::message_part_size ( ) const
inlinevirtualinherited

Find out the message part size supported by this scheme/key.

Returns
size of the message parts in bits

Reimplemented in Botan::DSA_PublicKey, Botan::ECDSA_PublicKey, and Botan::NR_PublicKey.

Definition at line 56 of file pk_keys.h.

56{ return 0; }

◆ message_parts()

virtual size_t Botan::Public_Key::message_parts ( ) const
inlinevirtualinherited

Find out the number of message parts supported by this scheme.

Returns
number of message parts

Reimplemented in Botan::DSA_PublicKey, Botan::ECDSA_PublicKey, and Botan::NR_PublicKey.

Definition at line 50 of file pk_keys.h.

50{ return 1; }

Referenced by Botan::X509_Object::check_signature(), and Botan::choose_sig_format().

◆ pkcs8_algorithm_identifier()

virtual AlgorithmIdentifier Botan::Private_Key::pkcs8_algorithm_identifier ( ) const
inlinevirtualinherited
Returns
PKCS #8 AlgorithmIdentifier for this key Might be different from the X.509 identifier, but normally is not

Definition at line 98 of file pk_keys.h.

99 { return algorithm_identifier(); }
virtual AlgorithmIdentifier algorithm_identifier() const =0

References Botan::Public_Key::algorithm_identifier().

Referenced by Botan::PKCS8::BER_encode().

◆ pkcs8_private_key()

MemoryVector< byte > Botan::DL_Scheme_PrivateKey::pkcs8_private_key ( ) const
virtualinherited
Returns
PKCS #8 private key encoding for this key object

Implements Botan::Private_Key.

Definition at line 36 of file dl_algo.cpp.

37 {
38 return DER_Encoder().encode(x).get_contents();
39 }

References Botan::DER_Encoder::encode(), Botan::DER_Encoder::get_contents(), and x.

◆ x509_subject_public_key()

MemoryVector< byte > Botan::DL_Scheme_PublicKey::x509_subject_public_key ( ) const
virtualinherited
Returns
X.509 subject key encoding for this key object

Implements Botan::Public_Key.

Definition at line 21 of file dl_algo.cpp.

22 {
23 return DER_Encoder().encode(y).get_contents();
24 }

References Botan::DER_Encoder::encode(), Botan::DER_Encoder::get_contents(), and y.

Member Data Documentation

◆ group

◆ x

◆ y


The documentation for this class was generated from the following files: