Botan 3.5.0
Crypto and TLS for C&
Botan::RSA_PublicKey Class Reference

#include <rsa.h>

Inheritance diagram for Botan::RSA_PublicKey:
Botan::Public_Key Botan::Asymmetric_Key Botan::RSA_PrivateKey

Public Member Functions

std::string algo_name () const override
 
AlgorithmIdentifier algorithm_identifier () const override
 
bool check_key (RandomNumberGenerator &rng, bool) const override
 
std::unique_ptr< PK_Ops::Encryptioncreate_encryption_op (RandomNumberGenerator &rng, std::string_view params, std::string_view provider) const override
 
std::unique_ptr< PK_Ops::KEM_Encryptioncreate_kem_encryption_op (std::string_view params, std::string_view provider) const override
 
std::unique_ptr< PK_Ops::Verificationcreate_verification_op (std::string_view params, std::string_view provider) const override
 
std::unique_ptr< PK_Ops::Verificationcreate_x509_verification_op (const AlgorithmIdentifier &alg_id, std::string_view provider) const override
 
virtual Signature_Format default_x509_signature_format () const
 
size_t estimated_strength () const override
 
std::string fingerprint_public (std::string_view alg="SHA-256") const
 
std::unique_ptr< Private_Keygenerate_another (RandomNumberGenerator &rng) const override
 
const BigIntget_e () const
 
const BigIntget_int_field (std::string_view field) const override
 
const BigIntget_n () const
 
OID get_oid () const
 
size_t key_length () const override
 
virtual size_t message_part_size () const
 
virtual size_t message_parts () const
 
virtual OID object_identifier () const
 
std::shared_ptr< const RSA_Public_Data > public_data () const
 
std::vector< uint8_t > public_key_bits () const override
 
std::vector< uint8_t > raw_public_key_bits () const override
 
 RSA_PublicKey (const AlgorithmIdentifier &alg_id, std::span< const uint8_t > key_bits)
 
 RSA_PublicKey (const BigInt &n, const BigInt &e)
 
std::vector< uint8_t > subject_public_key () const
 
bool supports_operation (PublicKeyOperation op) const override
 

Protected Member Functions

void init (BigInt &&n, BigInt &&e)
 
 RSA_PublicKey ()=default
 

Protected Attributes

std::shared_ptr< const RSA_Public_Data > m_public
 

Detailed Description

RSA Public Key

Definition at line 25 of file rsa.h.

Constructor & Destructor Documentation

◆ RSA_PublicKey() [1/3]

Botan::RSA_PublicKey::RSA_PublicKey ( const AlgorithmIdentifier & alg_id,
std::span< const uint8_t > key_bits )

Load a public key.

Parameters
alg_idthe X.509 algorithm identifier
key_bitsDER encoded public key bits

Definition at line 151 of file rsa.cpp.

151 {
152 BigInt n, e;
153 BER_Decoder(key_bits).start_sequence().decode(n).decode(e).end_cons();
154
155 init(std::move(n), std::move(e));
156}
int(* init)(CTX *)

References Botan::BER_Decoder::decode(), Botan::BER_Decoder::end_cons(), init, and Botan::BER_Decoder::start_sequence().

◆ RSA_PublicKey() [2/3]

Botan::RSA_PublicKey::RSA_PublicKey ( const BigInt & n,
const BigInt & e )

Create a public key.

  • n the modulus
  • e the exponent

Definition at line 163 of file rsa.cpp.

163 {
164 BigInt n = modulus;
165 BigInt e = exponent;
166 init(std::move(n), std::move(e));
167}

References init.

◆ RSA_PublicKey() [3/3]

Botan::RSA_PublicKey::RSA_PublicKey ( )
protecteddefault

Member Function Documentation

◆ algo_name()

std::string Botan::RSA_PublicKey::algo_name ( ) const
inlineoverridevirtual

Get the name of the underlying public key scheme.

Returns
name of the public key scheme

Implements Botan::Asymmetric_Key.

Definition at line 41 of file rsa.h.

41{ return "RSA"; }

◆ algorithm_identifier()

AlgorithmIdentifier Botan::RSA_PublicKey::algorithm_identifier ( ) const
overridevirtual
Returns
X.509 AlgorithmIdentifier for this key

Implements Botan::Public_Key.

Definition at line 177 of file rsa.cpp.

177 {
178 return AlgorithmIdentifier(object_identifier(), AlgorithmIdentifier::USE_NULL_PARAM);
179}
virtual OID object_identifier() const
Definition pk_keys.cpp:22

References Botan::Asymmetric_Key::object_identifier(), and Botan::AlgorithmIdentifier::USE_NULL_PARAM.

◆ check_key()

bool Botan::RSA_PublicKey::check_key ( RandomNumberGenerator & rng,
bool  ) const
overridevirtual

Implements Botan::Public_Key.

Definition at line 196 of file rsa.cpp.

196 {
197 if(get_n() < 35 || get_n().is_even() || get_e() < 3 || get_e().is_even()) {
198 return false;
199 }
200 return true;
201}
const BigInt & get_n() const
Definition rsa.cpp:136
const BigInt & get_e() const
Definition rsa.cpp:140

References get_e(), and get_n().

◆ create_encryption_op()

std::unique_ptr< PK_Ops::Encryption > Botan::RSA_PublicKey::create_encryption_op ( RandomNumberGenerator & rng,
std::string_view params,
std::string_view provider ) const
overridevirtual

This is an internal library function exposed on key types. In almost all cases applications should use wrappers in pubkey.h

Return an encryption operation for this key/params or throw

Parameters
rnga random number generator. The PK_Op may maintain a reference to the RNG and use it many times. The rng must outlive any operations which reference it.
paramsadditional parameters
providerthe provider to use

Reimplemented from Botan::Public_Key.

Definition at line 718 of file rsa.cpp.

720 {
721 if(provider == "base" || provider.empty()) {
722 return std::make_unique<RSA_Encryption_Operation>(*this, params);
723 }
724 throw Provider_Not_Found(algo_name(), provider);
725}
std::string algo_name() const override
Definition rsa.h:41

◆ create_kem_encryption_op()

std::unique_ptr< PK_Ops::KEM_Encryption > Botan::RSA_PublicKey::create_kem_encryption_op ( std::string_view params,
std::string_view provider ) const
overridevirtual

This is an internal library function exposed on key types. In almost all cases applications should use wrappers in pubkey.h

Return a KEM encryption operation for this key/params or throw

Parameters
paramsadditional parameters
providerthe provider to use

Reimplemented from Botan::Public_Key.

Definition at line 727 of file rsa.cpp.

728 {
729 if(provider == "base" || provider.empty()) {
730 return std::make_unique<RSA_KEM_Encryption_Operation>(*this, params);
731 }
732 throw Provider_Not_Found(algo_name(), provider);
733}

◆ create_verification_op()

std::unique_ptr< PK_Ops::Verification > Botan::RSA_PublicKey::create_verification_op ( std::string_view params,
std::string_view provider ) const
overridevirtual

This is an internal library function exposed on key types. In all cases applications should use wrappers in pubkey.h

Return a verification operation for this key/params or throw

Parameters
paramsadditional parameters
providerthe provider to use

Reimplemented from Botan::Public_Key.

Definition at line 735 of file rsa.cpp.

736 {
737 if(provider == "base" || provider.empty()) {
738 return std::make_unique<RSA_Verify_Operation>(*this, params);
739 }
740
741 throw Provider_Not_Found(algo_name(), provider);
742}

◆ create_x509_verification_op()

std::unique_ptr< PK_Ops::Verification > Botan::RSA_PublicKey::create_x509_verification_op ( const AlgorithmIdentifier & signature_algorithm,
std::string_view provider ) const
overridevirtual

This is an internal library function exposed on key types. In all cases applications should use wrappers in pubkey.h

Return a verification operation for this combination of key and signature algorithm or throw.

Parameters
signature_algorithmis the X.509 algorithm identifier encoding the padding scheme and hash hash function used in the signature if applicable.
providerthe provider to use

Reimplemented from Botan::Public_Key.

Definition at line 794 of file rsa.cpp.

795 {
796 if(provider == "base" || provider.empty()) {
797 return std::make_unique<RSA_Verify_Operation>(*this, parse_rsa_signature_algorithm(alg_id));
798 }
799
800 throw Provider_Not_Found(algo_name(), provider);
801}

◆ default_x509_signature_format()

virtual Signature_Format Botan::Public_Key::default_x509_signature_format ( ) const
inlinevirtualinherited

◆ estimated_strength()

size_t Botan::RSA_PublicKey::estimated_strength ( ) const
overridevirtual

Return the estimated strength of the underlying key against the best currently known attack. Note that this ignores anything but pure attacks against the key itself and do not take into account padding schemes, usage mistakes, etc which might reduce the strength. However it does suffice to provide an upper bound.

Returns
estimated strength in bits

Implements Botan::Asymmetric_Key.

Definition at line 173 of file rsa.cpp.

173 {
174 return if_work_factor(key_length());
175}
size_t key_length() const override
Definition rsa.cpp:169
size_t if_work_factor(size_t bits)

References Botan::if_work_factor(), and key_length().

◆ fingerprint_public()

std::string Botan::Public_Key::fingerprint_public ( std::string_view alg = "SHA-256") const
inherited
Returns
Hash of the subject public key

Definition at line 79 of file pk_keys.cpp.

79 {
80 return create_hex_fingerprint(subject_public_key(), hash_algo);
81}
std::vector< uint8_t > subject_public_key() const
Definition pk_keys.cpp:48
std::string create_hex_fingerprint(const uint8_t bits[], size_t bits_len, std::string_view hash_name)
Definition pk_keys.cpp:30

References Botan::create_hex_fingerprint(), and Botan::Public_Key::subject_public_key().

◆ generate_another()

std::unique_ptr< Private_Key > Botan::RSA_PublicKey::generate_another ( RandomNumberGenerator & rng) const
overridevirtual

Generate another (cryptographically independent) key pair using the same algorithm parameters as this key. This is most useful for algorithms that support PublicKeyOperation::KeyAgreement to generate a fitting ephemeral key pair. For other key types it might throw Not_Implemented.

Implements Botan::Asymmetric_Key.

Definition at line 132 of file rsa.cpp.

132 {
133 return std::make_unique<RSA_PrivateKey>(rng, m_public->public_modulus_bits(), m_public->get_e().to_u32bit());
134}
std::shared_ptr< const RSA_Public_Data > m_public
Definition rsa.h:91

References m_public.

◆ get_e()

const BigInt & Botan::RSA_PublicKey::get_e ( ) const
Returns
public exponent

Definition at line 140 of file rsa.cpp.

140 {
141 return m_public->get_e();
142}

References m_public.

Referenced by Botan::RSA_PrivateKey::check_key(), check_key(), Botan::RSA_PrivateKey::private_key_bits(), Botan::RSA_PrivateKey::public_key(), and public_key_bits().

◆ get_int_field()

const BigInt & Botan::RSA_PublicKey::get_int_field ( std::string_view field) const
overridevirtual

Access an algorithm specific field

If the field is not known for this algorithm, an Invalid_Argument is thrown. The interpretation of the result requires knowledge of which algorithm is involved. For instance for RSA "p" represents one of the secret primes, while for DSA "p" is the public prime.

Some algorithms may not implement this method at all.

This is primarily used to implement the FFI botan_pubkey_get_field and botan_privkey_get_field functions.

Reimplemented from Botan::Asymmetric_Key.

Definition at line 122 of file rsa.cpp.

122 {
123 if(field == "n") {
124 return m_public->get_n();
125 } else if(field == "e") {
126 return m_public->get_e();
127 } else {
128 return Public_Key::get_int_field(field);
129 }
130}
virtual const BigInt & get_int_field(std::string_view field) const
Definition pk_keys.cpp:18

References Botan::Asymmetric_Key::get_int_field(), and m_public.

Referenced by Botan::RSA_PrivateKey::get_int_field().

◆ get_n()

const BigInt & Botan::RSA_PublicKey::get_n ( ) const
Returns
public modulus

Definition at line 136 of file rsa.cpp.

136 {
137 return m_public->get_n();
138}

References m_public.

Referenced by Botan::RSA_PrivateKey::check_key(), check_key(), Botan::RSA_PrivateKey::private_key_bits(), Botan::RSA_PrivateKey::public_key(), and public_key_bits().

◆ get_oid()

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

Deprecated version of object_identifier

Definition at line 132 of file pk_keys.h.

132{ return this->object_identifier(); }

◆ init()

void Botan::RSA_PublicKey::init ( BigInt && n,
BigInt && e )
protected

Definition at line 144 of file rsa.cpp.

144 {
145 if(n.is_negative() || n.is_even() || n.bits() < 5 /* n >= 3*5 */ || e.is_negative() || e.is_even()) {
146 throw Decoding_Error("Invalid RSA public key parameters");
147 }
148 m_public = std::make_shared<RSA_Public_Data>(std::move(n), std::move(e));
149}

References m_public.

Referenced by Botan::RSA_PrivateKey::RSA_PrivateKey(), Botan::RSA_PrivateKey::RSA_PrivateKey(), and Botan::RSA_PrivateKey::RSA_PrivateKey().

◆ key_length()

size_t Botan::RSA_PublicKey::key_length ( ) const
overridevirtual

Return an integer value best approximating the length of the primary security parameter. For example for RSA this will be the size of the modulus, for ECDSA the size of the ECC group, and for McEliece the size of the code will be returned.

Implements Botan::Public_Key.

Definition at line 169 of file rsa.cpp.

169 {
170 return m_public->public_modulus_bits();
171}

References m_public.

Referenced by estimated_strength().

◆ message_part_size()

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

Returns how large each of the message parts refered to by message_parts() is

This function is public but applications should have few reasons to ever call this.

Returns
size of the message parts in bits

Reimplemented in Botan::DSA_PublicKey, Botan::ECDSA_PublicKey, Botan::ECGDSA_PublicKey, Botan::ECKCDSA_PublicKey, Botan::GOST_3410_PublicKey, and Botan::SM2_PublicKey.

Definition at line 199 of file pk_keys.h.

199{ return 0; }

Referenced by Botan::PK_Signer::PK_Signer(), Botan::PK_Verifier::PK_Verifier(), and Botan::PK_Verifier::PK_Verifier().

◆ message_parts()

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

Returns more than 1 if the output of this algorithm (ciphertext, signature) should be treated as more than one value. This is used for algorithms like DSA and ECDSA, where the (r,s) output pair can be encoded as either a plain binary list or a TLV tagged DER encoding depending on the protocol.

This function is public but applications should have few reasons to ever call this.

Returns
number of message parts

Reimplemented in Botan::DSA_PublicKey, Botan::ECDSA_PublicKey, Botan::ECGDSA_PublicKey, Botan::ECKCDSA_PublicKey, Botan::GOST_3410_PublicKey, and Botan::SM2_PublicKey.

Definition at line 188 of file pk_keys.h.

188{ return 1; }

Referenced by Botan::PK_Signer::PK_Signer(), Botan::PK_Verifier::PK_Verifier(), and Botan::PK_Verifier::PK_Verifier().

◆ object_identifier()

OID Botan::Asymmetric_Key::object_identifier ( ) const
virtualinherited

◆ public_data()

std::shared_ptr< const RSA_Public_Data > Botan::RSA_PublicKey::public_data ( ) const

Definition at line 118 of file rsa.cpp.

118 {
119 return m_public;
120}

References m_public.

◆ public_key_bits()

std::vector< uint8_t > Botan::RSA_PublicKey::public_key_bits ( ) const
overridevirtual
Returns
BER encoded public key bits

Implements Botan::Public_Key.

Definition at line 185 of file rsa.cpp.

185 {
186 std::vector<uint8_t> output;
187 DER_Encoder der(output);
188 der.start_sequence().encode(get_n()).encode(get_e()).end_cons();
189
190 return output;
191}

References Botan::DER_Encoder::encode(), Botan::DER_Encoder::end_cons(), get_e(), get_n(), and Botan::DER_Encoder::start_sequence().

◆ raw_public_key_bits()

std::vector< uint8_t > Botan::RSA_PublicKey::raw_public_key_bits ( ) const
overridevirtual
Returns
binary public key bits, with no additional encoding

For key agreements this is an alias for PK_Key_Agreement_Key::public_value.

Note: some algorithms (for example RSA) do not have an obvious encoding for this value due to having many different values, and thus throw Not_Implemented when invoking this method.

Implements Botan::Public_Key.

Definition at line 181 of file rsa.cpp.

181 {
182 throw Not_Implemented("an RSA public key does not provide a raw binary representation.");
183}

◆ subject_public_key()

std::vector< uint8_t > Botan::Public_Key::subject_public_key ( ) const
inherited
Returns
X.509 subject key encoding for this key object

Definition at line 48 of file pk_keys.cpp.

48 {
49 std::vector<uint8_t> output;
50
51 DER_Encoder(output)
52 .start_sequence()
53 .encode(algorithm_identifier())
55 .end_cons();
56
57 return output;
58}
virtual AlgorithmIdentifier algorithm_identifier() const =0
virtual std::vector< uint8_t > public_key_bits() const =0

References Botan::Public_Key::algorithm_identifier(), Botan::BitString, Botan::DER_Encoder::encode(), Botan::DER_Encoder::end_cons(), Botan::Public_Key::public_key_bits(), and Botan::DER_Encoder::start_sequence().

Referenced by Botan::X509::BER_encode(), Botan::PKCS10_Request::create(), Botan::Public_Key::fingerprint_public(), and Botan::X509::PEM_encode().

◆ supports_operation()

bool Botan::RSA_PublicKey::supports_operation ( PublicKeyOperation op) const
overridevirtual

Return true if this key could be used for the specified type of operation.

Implements Botan::Asymmetric_Key.

Definition at line 158 of file rsa.cpp.

References Botan::Encryption, Botan::KeyEncapsulation, and Botan::Signature.

Member Data Documentation

◆ m_public

std::shared_ptr<const RSA_Public_Data> Botan::RSA_PublicKey::m_public
protected

Definition at line 91 of file rsa.h.

Referenced by generate_another(), get_e(), get_int_field(), get_n(), init(), key_length(), and public_data().


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