Botan 3.7.1
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 Botan::TPM2::RSA_PrivateKey Botan::TPM2::RSA_PublicKey

Public Member Functions

virtual Signature_Format _default_x509_signature_format () const
 
virtual std::optional< size_t > _signature_element_size_for_DER_encoding () const
 
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
 
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
 
size_t message_part_size () const
 
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 157 of file rsa.cpp.

157 {
158 BigInt n, e;
159 BER_Decoder(key_bits).start_sequence().decode(n).decode(e).end_cons();
160
161 init(std::move(n), std::move(e));
162}
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 169 of file rsa.cpp.

169 {
170 BigInt n = modulus;
171 BigInt e = exponent;
172 init(std::move(n), std::move(e));
173}

References init.

◆ RSA_PublicKey() [3/3]

Botan::RSA_PublicKey::RSA_PublicKey ( )
protecteddefault

Member Function Documentation

◆ _default_x509_signature_format()

Signature_Format Botan::Asymmetric_Key::_default_x509_signature_format ( ) const
virtualinherited

◆ _signature_element_size_for_DER_encoding()

virtual std::optional< size_t > Botan::Asymmetric_Key::_signature_element_size_for_DER_encoding ( ) const
inlinevirtualinherited

Certain signatures schemes such as ECDSA have more than one element, and certain unfortunate protocols decided the thing to do was not concatenate them as normally done, but instead DER encode each of the elements as independent values.

If this returns a value x then the signature is checked to be exactly 2*x bytes and split in half for DER encoding.

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 136 of file pk_keys.h.

136{ return {}; }

Referenced by Botan::Asymmetric_Key::_default_x509_signature_format(), Botan::PK_Signer::PK_Signer(), Botan::PK_Verifier::PK_Verifier(), and Botan::PK_Verifier::PK_Verifier().

◆ 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 183 of file rsa.cpp.

183 {
184 return AlgorithmIdentifier(object_identifier(), AlgorithmIdentifier::USE_NULL_PARAM);
185}
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::Asymmetric_Key.

Definition at line 202 of file rsa.cpp.

202 {
203 if(get_n() < 35 || get_n().is_even() || get_e() < 3 || get_e().is_even()) {
204 return false;
205 }
206 return true;
207}
const BigInt & get_n() const
Definition rsa.cpp:142
const BigInt & get_e() const
Definition rsa.cpp:146

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.

Reimplemented in Botan::TPM2::RSA_PublicKey.

Definition at line 730 of file rsa.cpp.

732 {
733 if(provider == "base" || provider.empty()) {
734 return std::make_unique<RSA_Encryption_Operation>(*this, params);
735 }
736 throw Provider_Not_Found(algo_name(), provider);
737}
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 739 of file rsa.cpp.

740 {
741 if(provider == "base" || provider.empty()) {
742 return std::make_unique<RSA_KEM_Encryption_Operation>(*this, params);
743 }
744 throw Provider_Not_Found(algo_name(), provider);
745}

◆ 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.

Reimplemented in Botan::TPM2::RSA_PublicKey.

Definition at line 747 of file rsa.cpp.

748 {
749 if(provider == "base" || provider.empty()) {
750 return std::make_unique<RSA_Verify_Operation>(*this, params);
751 }
752
753 throw Provider_Not_Found(algo_name(), provider);
754}

◆ 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 806 of file rsa.cpp.

807 {
808 if(provider == "base" || provider.empty()) {
809 return std::make_unique<RSA_Verify_Operation>(*this, parse_rsa_signature_algorithm(alg_id));
810 }
811
812 throw Provider_Not_Found(algo_name(), provider);
813}

◆ default_x509_signature_format()

Signature_Format Botan::Public_Key::default_x509_signature_format ( ) const
inlineinherited

Definition at line 227 of file pk_keys.h.

227 {
229 }
virtual Signature_Format _default_x509_signature_format() const
Definition pk_keys.cpp:30

◆ 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 179 of file rsa.cpp.

179 {
180 return if_work_factor(key_length());
181}
size_t key_length() const override
Definition rsa.cpp:175
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 87 of file pk_keys.cpp.

87 {
88 return create_hex_fingerprint(subject_public_key(), hash_algo);
89}
std::vector< uint8_t > subject_public_key() const
Definition pk_keys.cpp:56
std::string create_hex_fingerprint(const uint8_t bits[], size_t bits_len, std::string_view hash_name)
Definition pk_keys.cpp:38

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.

Reimplemented in Botan::TPM2::RSA_PublicKey.

Definition at line 138 of file rsa.cpp.

138 {
139 return std::make_unique<RSA_PrivateKey>(rng, m_public->public_modulus_bits(), m_public->get_e().to_u32bit());
140}
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 146 of file rsa.cpp.

146 {
147 return m_public->get_e();
148}

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.

TODO(Botan4) Change this to return by value

Reimplemented from Botan::Asymmetric_Key.

Definition at line 128 of file rsa.cpp.

128 {
129 if(field == "n") {
130 return m_public->get_n();
131 } else if(field == "e") {
132 return m_public->get_e();
133 } else {
134 return Public_Key::get_int_field(field);
135 }
136}
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 142 of file rsa.cpp.

142 {
143 return m_public->get_n();
144}

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 160 of file pk_keys.h.

160{ return this->object_identifier(); }

◆ init()

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

Definition at line 150 of file rsa.cpp.

150 {
151 if(n.is_negative() || n.is_even() || n.bits() < 5 /* n >= 3*5 */ || e.is_negative() || e.is_even()) {
152 throw Decoding_Error("Invalid RSA public key parameters");
153 }
154 m_public = std::make_shared<RSA_Public_Data>(std::move(n), std::move(e));
155}

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 175 of file rsa.cpp.

175 {
176 return m_public->public_modulus_bits();
177}

References m_public.

Referenced by estimated_strength().

◆ message_part_size()

size_t Botan::Public_Key::message_part_size ( ) const
inlineinherited

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

Definition at line 220 of file pk_keys.h.

220 {
221 return _signature_element_size_for_DER_encoding().value_or(0);
222 }

◆ message_parts()

size_t Botan::Public_Key::message_parts ( ) const
inlineinherited

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

Definition at line 207 of file pk_keys.h.

207 {
209 }

◆ object_identifier()

◆ public_data()

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

Definition at line 124 of file rsa.cpp.

124 {
125 return m_public;
126}

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 191 of file rsa.cpp.

191 {
192 std::vector<uint8_t> output;
193 DER_Encoder der(output);
194 der.start_sequence().encode(get_n()).encode(get_e()).end_cons();
195
196 return output;
197}

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.

Reimplemented in Botan::TPM2::RSA_PublicKey.

Definition at line 187 of file rsa.cpp.

187 {
188 throw Not_Implemented("an RSA public key does not provide a raw binary representation.");
189}

◆ 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 56 of file pk_keys.cpp.

56 {
57 std::vector<uint8_t> output;
58
59 DER_Encoder(output)
60 .start_sequence()
61 .encode(algorithm_identifier())
63 .end_cons();
64
65 return output;
66}
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.

Reimplemented in Botan::TPM2::RSA_PublicKey.

Definition at line 164 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: