Botan::Ed25519_PublicKey Class Reference

#include <ed25519.h>

Inheritance diagram for Botan::Ed25519_PublicKey:

Public Member Functions
std::string	algo_name () const override
AlgorithmIdentifier	algorithm_identifier () const override
bool	check_key (RandomNumberGenerator &rng, bool strong) const override
virtual std::unique_ptr< PK_Ops::Encryption >	create_encryption_op (RandomNumberGenerator &rng, std::string_view params, std::string_view provider) const
virtual std::unique_ptr< PK_Ops::KEM_Encryption >	create_kem_encryption_op (std::string_view params, std::string_view provider) const
std::unique_ptr< PK_Ops::Verification >	create_verification_op (std::string_view params, std::string_view provider) const override
std::unique_ptr< PK_Ops::Verification >	create_x509_verification_op (const AlgorithmIdentifier &signature_algorithm, std::string_view provider) const override
virtual Signature_Format	default_x509_signature_format () const
	Ed25519_PublicKey (const AlgorithmIdentifier &alg_id, std::span< const uint8_t > key_bits)
	Ed25519_PublicKey (const uint8_t pub_key[], size_t len)
	Ed25519_PublicKey (std::span< const uint8_t > pub)
size_t	estimated_strength () const override
std::string	fingerprint_public (std::string_view alg="SHA-256") const
std::unique_ptr< Private_Key >	generate_another (RandomNumberGenerator &rng) const final
virtual const BigInt &	get_int_field (std::string_view field) const
OID	get_oid () const
const std::vector< uint8_t > &	get_public_key () 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::vector< uint8_t >	public_key_bits () const override
std::vector< uint8_t >	raw_public_key_bits () const override
std::vector< uint8_t >	subject_public_key () const
bool	supports_operation (PublicKeyOperation op) const override

Protected Member Functions
	Ed25519_PublicKey ()=default

Protected Attributes
std::vector< uint8_t >	m_public

Detailed Description

Definition at line 18 of file ed25519.h.

Constructor & Destructor Documentation

Ed25519_PublicKey() [1/4]

Botan::Ed25519_PublicKey::Ed25519_PublicKey	(	const AlgorithmIdentifier &	alg_id,
		std::span< const uint8_t >	key_bits )

Create a Ed25519 Public Key.

Parameters

alg_id	the X.509 algorithm identifier
key_bits	DER encoded public key bits

Definition at line 74 of file ed25519_key.cpp.

                                                                                                  {
   m_public.assign(key_bits.begin(), key_bits.end());
 
   if(m_public.size() != 32) {
      throw Decoding_Error("Invalid size for Ed25519 public key");
   }
}

References m_public.

Ed25519_PublicKey() [2/4]

Botan::Ed25519_PublicKey::Ed25519_PublicKey ( std::span< const uint8_t > pub )

inline

Definition at line 47 of file ed25519.h.

: Ed25519_PublicKey(pub.data(), pub.size()) {}

Ed25519_PublicKey() [3/4]

Botan::Ed25519_PublicKey::Ed25519_PublicKey	(	const uint8_t	pub_key[],
		size_t	len )

Definition at line 67 of file ed25519_key.cpp.

                                                                            {
   if(pub_len != 32) {
      throw Decoding_Error("Invalid length for Ed25519 key");
   }
   m_public.assign(pub_key, pub_key + pub_len);
}

References m_public.

Ed25519_PublicKey() [4/4]

Botan::Ed25519_PublicKey::Ed25519_PublicKey ( )

protecteddefault

Member Function Documentation

algo_name()

std::string Botan::Ed25519_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 20 of file ed25519.h.

{ return "Ed25519"; }

algorithm_identifier()

AlgorithmIdentifier Botan::Ed25519_PublicKey::algorithm_identifier ( ) const

overridevirtual

Returns

X.509 AlgorithmIdentifier for this key

Implements Botan::Public_Key.

Definition at line 23 of file ed25519_key.cpp.

                                                                  {
   return AlgorithmIdentifier(object_identifier(), AlgorithmIdentifier::USE_EMPTY_PARAM);
}

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

check_key()

bool Botan::Ed25519_PublicKey::check_key ( RandomNumberGenerator & rng, bool strong ) const

overridevirtual

Implements Botan::Public_Key.

Definition at line 27 of file ed25519_key.cpp.

                                                                        {
   if(m_public.size() != 32) {
      return false;
   }
 
   /*
   This function was derived from public domain code in Tor's blinding.c
   */
 
   const uint8_t identity_element[32] = {1};
   if(CT::is_equal(m_public.data(), identity_element, 32).as_bool()) {
      return false;
   }
 
   // The order of the Ed25519 group encoded
   const uint8_t modm_m[32] = {0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, 0xd6, 0x9c, 0xf7,
                               0xa2, 0xde, 0xf9, 0xde, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                               0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10};
 
   const unsigned char zero[32] = {0};
 
   unsigned char pkcopy[32];
 
   copy_mem(pkcopy, m_public.data(), 32);
   pkcopy[31] ^= (1 << 7);  // flip sign
   ge_p3 point;
   if(ge_frombytes_negate_vartime(&point, pkcopy) != 0) {
      return false;
   }
 
   uint8_t result[32];
   ge_double_scalarmult_vartime(result, modm_m, &point, zero);
 
   if(!CT::is_equal(result, identity_element, 32).as_bool()) {
      return false;
   }
 
   return true;
}

References Botan::copy_mem(), Botan::ge_double_scalarmult_vartime(), Botan::ge_frombytes_negate_vartime(), Botan::CT::is_equal(), and m_public.

create_encryption_op()

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

virtualinherited

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

rng	a 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.
params	additional parameters
provider	the provider to use

Reimplemented in Botan::ElGamal_PublicKey, Botan::RSA_PublicKey, Botan::SM2_PublicKey, and Botan::TPM2::RSA_PublicKey.

Definition at line 90 of file pk_keys.cpp.

                                                                                             {
   throw Lookup_Error(fmt("{} does not support encryption", algo_name()));
}

References Botan::Asymmetric_Key::algo_name(), and Botan::fmt().

Referenced by Botan::PK_Encryptor_EME::PK_Encryptor_EME().

create_kem_encryption_op()

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

virtualinherited

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

params	additional parameters
provider	the provider to use

Reimplemented in Botan::FrodoKEM_PublicKey, Botan::Kyber_PublicKey, Botan::McEliece_PublicKey, Botan::RSA_PublicKey, Botan::TLS::Hybrid_KEM_PublicKey, and Botan::TLS::KEX_to_KEM_Adapter_PublicKey.

Definition at line 96 of file pk_keys.cpp.

                                                                                                     {
   throw Lookup_Error(fmt("{} does not support KEM encryption", algo_name()));
}

References Botan::Asymmetric_Key::algo_name(), and Botan::fmt().

Referenced by Botan::PK_KEM_Encryptor::PK_KEM_Encryptor().

create_verification_op()

std::unique_ptr< PK_Ops::Verification > Botan::Ed25519_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

params	additional parameters
provider	the provider to use

Reimplemented from Botan::Public_Key.

Definition at line 276 of file ed25519_key.cpp.

                                                                                                               {
   if(provider == "base" || provider.empty()) {
      if(params.empty() || params == "Identity" || params == "Pure") {
         return std::make_unique<Ed25519_Pure_Verify_Operation>(*this);
      } else if(params == "Ed25519ph") {
         return std::make_unique<Ed25519_Hashed_Verify_Operation>(*this, "SHA-512", true);
      } else {
         return std::make_unique<Ed25519_Hashed_Verify_Operation>(*this, params, false);
      }
   }
   throw Provider_Not_Found(algo_name(), provider);
}

create_x509_verification_op()

std::unique_ptr< PK_Ops::Verification > Botan::Ed25519_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_algorithm	is the X.509 algorithm identifier encoding the padding scheme and hash hash function used in the signature if applicable.
provider	the provider to use

Reimplemented from Botan::Public_Key.

Definition at line 290 of file ed25519_key.cpp.

                                                                                                                    {
   if(provider == "base" || provider.empty()) {
      if(alg_id != this->algorithm_identifier()) {
         throw Decoding_Error("Unexpected AlgorithmIdentifier for Ed25519 X509 signature");
      }
 
      return std::make_unique<Ed25519_Pure_Verify_Operation>(*this);
   }
   throw Provider_Not_Found(algo_name(), provider);
}

default_x509_signature_format()

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

inlinevirtualinherited

Reimplemented in Botan::GOST_3410_PublicKey.

Definition at line 201 of file pk_keys.h.

                                                                     {
         return (this->message_parts() >= 2) ? Signature_Format::DerSequence : Signature_Format::Standard;
      }

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

estimated_strength()

size_t Botan::Ed25519_PublicKey::estimated_strength ( ) const

inlineoverridevirtual

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 22 of file ed25519.h.

{ return 128; }

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.

                                                                       {
   return create_hex_fingerprint(subject_public_key(), hash_algo);
}

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

generate_another()

std::unique_ptr< Private_Key > Botan::Ed25519_PublicKey::generate_another ( RandomNumberGenerator & rng ) const

finalvirtual

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 90 of file ed25519_key.cpp.

                                                                                               {
   return std::make_unique<Ed25519_PrivateKey>(rng);
}

get_int_field()

const BigInt & Botan::Asymmetric_Key::get_int_field ( std::string_view field ) const

virtualinherited

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 in Botan::DH_PrivateKey, Botan::DH_PublicKey, Botan::DSA_PrivateKey, Botan::DSA_PublicKey, Botan::EC_PrivateKey, Botan::EC_PublicKey, Botan::ElGamal_PrivateKey, Botan::ElGamal_PublicKey, Botan::RSA_PrivateKey, and Botan::RSA_PublicKey.

Definition at line 18 of file pk_keys.cpp.

                                                                      {
   throw Unknown_PK_Field_Name(algo_name(), field);
}

References Botan::Asymmetric_Key::algo_name().

Referenced by Botan::EC_PublicKey::get_int_field(), and Botan::RSA_PublicKey::get_int_field().

get_oid()

OID Botan::Public_Key::get_oid ( ) const

inlineinherited

Deprecated version of object_identifier

Definition at line 132 of file pk_keys.h.

{ return this->object_identifier(); }

get_public_key()

const std::vector< uint8_t > & Botan::Ed25519_PublicKey::get_public_key ( ) const

inline

Definition at line 38 of file ed25519.h.

{ return m_public; }

Referenced by Botan::Ed25519_PrivateKey::public_key().

key_length()

size_t Botan::Ed25519_PublicKey::key_length ( ) const

inlineoverridevirtual

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 24 of file ed25519.h.

{ return 255; }

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.

{ 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.

{ 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

Get the OID of the underlying public key scheme.

Returns

OID of the public key scheme

Reimplemented in Botan::Dilithium_PublicKey, Botan::FrodoKEM_PublicKey, Botan::HSS_LMS_PublicKey, Botan::Kyber_PublicKey, and Botan::SphincsPlus_PublicKey.

Definition at line 22 of file pk_keys.cpp.

                                            {
   try {
      return OID::from_string(algo_name());
   } catch(Lookup_Error&) {
      throw Lookup_Error(fmt("Public key algorithm {} has no defined OIDs", algo_name()));
   }
}

References Botan::Asymmetric_Key::algo_name(), Botan::fmt(), and Botan::OID::from_string().

Referenced by Botan::DH_PublicKey::algorithm_identifier(), Botan::DSA_PublicKey::algorithm_identifier(), Botan::EC_PublicKey::algorithm_identifier(), algorithm_identifier(), Botan::Ed448_PublicKey::algorithm_identifier(), Botan::ElGamal_PublicKey::algorithm_identifier(), Botan::GOST_3410_PublicKey::algorithm_identifier(), Botan::McEliece_PublicKey::algorithm_identifier(), Botan::RSA_PublicKey::algorithm_identifier(), Botan::TPM_PrivateKey::algorithm_identifier(), Botan::X25519_PublicKey::algorithm_identifier(), and Botan::X448_PublicKey::algorithm_identifier().

public_key_bits()

std::vector< uint8_t > Botan::Ed25519_PublicKey::public_key_bits ( ) const

overridevirtual

Returns

BER encoded public key bits

Implements Botan::Public_Key.

Definition at line 86 of file ed25519_key.cpp.

                                                            {
   return raw_public_key_bits();
}

References raw_public_key_bits().

raw_public_key_bits()

std::vector< uint8_t > Botan::Ed25519_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 82 of file ed25519_key.cpp.

                                                                {
   return m_public;
}

References m_public.

Referenced by public_key_bits().

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.

                                                        {
   std::vector<uint8_t> output;
 
   DER_Encoder(output)
      .start_sequence()
      .encode(algorithm_identifier())
      .encode(public_key_bits(), ASN1_Type::BitString)
      .end_cons();
 
   return output;
}

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::Ed25519_PublicKey::supports_operation ( PublicKeyOperation op ) const

inlineoverridevirtual

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

Implements Botan::Asymmetric_Key.

Definition at line 36 of file ed25519.h.

{ return (op == PublicKeyOperation::Signature); }

Member Data Documentation

m_public

std::vector<uint8_t> Botan::Ed25519_PublicKey::m_public

protected

Definition at line 59 of file ed25519.h.

Referenced by check_key(), Botan::Ed25519_PrivateKey::Ed25519_PrivateKey(), Botan::Ed25519_PrivateKey::Ed25519_PrivateKey(), Botan::Ed25519_PrivateKey::Ed25519_PrivateKey(), Ed25519_PublicKey(), Ed25519_PublicKey(), and raw_public_key_bits().

---

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

• src/lib/pubkey/ed25519/ed25519.h
• src/lib/pubkey/ed25519/ed25519_key.cpp