#include <hybrid_public_key.h>

Inheritance diagram for Botan::TLS::Hybrid_KEM_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 strong) const override
virtual std::unique_ptr< PK_Ops::Encryption >	create_encryption_op (RandomNumberGenerator &rng, std::string_view params, std::string_view provider) const
std::unique_ptr< PK_Ops::KEM_Encryption >	create_kem_encryption_op (std::string_view params, std::string_view provider="base") const override
virtual std::unique_ptr< PK_Ops::Verification >	create_verification_op (std::string_view params, std::string_view provider) const
virtual std::unique_ptr< PK_Ops::Verification >	create_x509_verification_op (const AlgorithmIdentifier &signature_algorithm, std::string_view provider) const
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_Key >	generate_another (RandomNumberGenerator &rng) const final
virtual const BigInt &	get_int_field (std::string_view field) const
OID	get_oid () const
	Hybrid_KEM_PublicKey (std::vector< std::unique_ptr< Public_Key > > pks)
size_t	key_length () const override
size_t	message_part_size () const
size_t	message_parts () const
virtual OID	object_identifier () const
std::vector< uint8_t >	public_key_bits () const override
const std::vector< std::unique_ptr< Public_Key > > &	public_keys () const
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

Static Public Member Functions
static std::unique_ptr< Hybrid_KEM_PublicKey >	load_for_group (Group_Params group, std::span< const uint8_t > concatenated_public_values)

Protected Member Functions
std::vector< std::unique_ptr< Private_Key > >	generate_other_sks_from_pks (RandomNumberGenerator &rng) const
	Helper function for generate_another. Generate a new private key for each public key in this hybrid key.
	Hybrid_KEM_PublicKey ()=default

Detailed Description

Composes a number of public keys as defined in this IETF draft: https://datatracker.ietf.org/doc/html/draft-ietf-tls-hybrid-design-04

To an upstream user, this composite key pair is presented as a KEM. Each individual key pair must either work as a KEX or as a KEM. Currently, the class can deal with ECC keys and Kyber.

The typical use case provides exactly two keys (one traditional KEX and one post-quantum secure KEM). However, this class technically allows composing any number of such keys. Composing more than two keys simply generates a shared secret based on more algorithms.

Note that this class is not generic enough for arbitrary use cases but serializes and parses keys and ciphertexts as described in the above-mentioned IETF draft for a post-quantum TLS 1.3.

Definition at line 41 of file hybrid_public_key.h.

Constructor & Destructor Documentation

◆ Hybrid_KEM_PublicKey() [1/2]

Botan::TLS::Hybrid_KEM_PublicKey::Hybrid_KEM_PublicKey ( std::vector< std::unique_ptr< Public_Key > > pks )

explicit

Definition at line 258 of file hybrid_public_key.cpp.

258 :

259 Hybrid_PublicKey(convert_kex_to_kem_pks(std::move(pks))) {}

Botan::Hybrid_PublicKey::Hybrid_PublicKey

Hybrid_PublicKey()=default

References Hybrid_KEM_PublicKey(), and Botan::Hybrid_PublicKey::Hybrid_PublicKey().

Referenced by Hybrid_KEM_PublicKey().

◆ Hybrid_KEM_PublicKey() [2/2]

Botan::TLS::Hybrid_KEM_PublicKey::Hybrid_KEM_PublicKey ( )

protecteddefault

Member Function Documentation

◆ _default_x509_signature_format()

Signature_Format Botan::Asymmetric_Key::_default_x509_signature_format ( ) const

virtualinherited

Reimplemented in Botan::GOST_3410_PublicKey.

Definition at line 30 of file pk_keys.cpp.

                                                                      {
   if(_signature_element_size_for_DER_encoding()) {
      return Signature_Format::DerSequence;
   } else {
      return Signature_Format::Standard;
   }
}

References _signature_element_size_for_DER_encoding(), Botan::DerSequence, and Botan::Standard.

Referenced by Botan::X509_Object::choose_sig_format(), Botan::Public_Key::default_x509_signature_format(), and Botan::PK_Verifier::PK_Verifier().

◆ _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 137 of file pk_keys.h.

137{ return {}; }

Referenced by _default_x509_signature_format(), Botan::Public_Key::message_part_size(), Botan::Public_Key::message_parts(), Botan::PK_Verifier::PK_Verifier(), and Botan::PK_Verifier::PK_Verifier().

◆ algo_name()

std::string Botan::TLS::Hybrid_KEM_PublicKey::algo_name ( ) const

overridevirtual

Get the name of the underlying public key scheme.

Returns: name of the public key scheme

Implements Botan::Asymmetric_Key.

Definition at line 265 of file hybrid_public_key.cpp.

                                                {
   std::ostringstream algo_name("Hybrid(");
   for(size_t i = 0; i < public_keys().size(); ++i) {
      if(i > 0) {
         algo_name << ",";
      }
      algo_name << public_keys().at(i)->algo_name();
   }
   algo_name << ")";
   return algo_name.str();
}

References algo_name(), and Botan::Hybrid_PublicKey::public_keys().

Referenced by algo_name().

◆ algorithm_identifier()

AlgorithmIdentifier Botan::TLS::Hybrid_KEM_PublicKey::algorithm_identifier ( ) const

overridevirtual

Returns: X.509 AlgorithmIdentifier for this key

Implements Botan::Public_Key.

Definition at line 277 of file hybrid_public_key.cpp.

                                                                     {
   throw Botan::Not_Implemented("Hybrid keys don't have an algorithm identifier");
}

◆ check_key()

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

overridevirtualinherited

Implements Botan::Asymmetric_Key.

Definition at line 31 of file hybrid_kem.cpp.

                                                                              {
   return reduce(public_keys(), true, [&](bool ckr, const auto& key) { return ckr && key->check_key(rng, strong); });
}

References public_keys(), and Botan::reduce().

◆ 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 98 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< Botan::PK_Ops::KEM_Encryption > Botan::TLS::Hybrid_KEM_PublicKey::create_kem_encryption_op	(	std::string_view	params,
		std::string_view	provider = "base" ) 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

params	additional parameters
provider	the provider to use

Reimplemented from Botan::Public_Key.

Definition at line 302 of file hybrid_public_key.cpp.

                                                         {
   if(params != "Raw" && !params.empty()) {
      throw Botan::Invalid_Argument("Hybrid KEM encryption does not support KDFs");
   }
   return std::make_unique<Hybrid_TLS_KEM_Encryptor>(public_keys(), provider);
}

References Botan::Hybrid_PublicKey::public_keys().

◆ create_verification_op()

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

virtualinherited

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 in Botan::Dilithium_PublicKey, Botan::DSA_PublicKey, Botan::ECDSA_PublicKey, Botan::ECGDSA_PublicKey, Botan::ECKCDSA_PublicKey, Botan::Ed25519_PublicKey, Botan::Ed448_PublicKey, Botan::GOST_3410_PublicKey, Botan::HSS_LMS_PublicKey, Botan::RSA_PublicKey, Botan::SM2_PublicKey, Botan::SphincsPlus_PublicKey, Botan::TPM2::EC_PublicKey, Botan::TPM2::RSA_PublicKey, and Botan::XMSS_PublicKey.

Definition at line 109 of file pk_keys.cpp.

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

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

Referenced by Botan::PK_Verifier::PK_Verifier().

◆ create_x509_verification_op()

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

virtualinherited

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 in Botan::Dilithium_PublicKey, Botan::DSA_PublicKey, Botan::ECDSA_PublicKey, Botan::ECGDSA_PublicKey, Botan::ECKCDSA_PublicKey, Botan::Ed25519_PublicKey, Botan::Ed448_PublicKey, Botan::GOST_3410_PublicKey, Botan::HSS_LMS_PublicKey, Botan::RSA_PublicKey, Botan::SphincsPlus_PublicKey, and Botan::XMSS_PublicKey.

Definition at line 114 of file pk_keys.cpp.

                                                                                                      {
   throw Lookup_Error(fmt("{} does not support X.509 verification", algo_name()));
}

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

Referenced by Botan::PK_Verifier::PK_Verifier().

◆ default_x509_signature_format()

Signature_Format Botan::Public_Key::default_x509_signature_format ( ) const

inlineinherited

Definition at line 229 of file pk_keys.h.

                                                               {
         return _default_x509_signature_format();
      }

References Botan::Asymmetric_Key::_default_x509_signature_format(), and default_x509_signature_format().

Referenced by default_x509_signature_format().

◆ estimated_strength()

size_t Botan::Hybrid_PublicKey::estimated_strength ( ) const

inlineoverridevirtualinherited

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 47 of file hybrid_kem.h.

47{ return m_estimated_strength; }

◆ 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.

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

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

Referenced by public_key_bits().

◆ generate_another()

std::unique_ptr< Private_Key > Botan::TLS::Hybrid_KEM_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 298 of file hybrid_public_key.cpp.

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

References Botan::Hybrid_PublicKey::generate_other_sks_from_pks().

◆ generate_other_sks_from_pks()

std::vector< std::unique_ptr< Private_Key > > Botan::Hybrid_PublicKey::generate_other_sks_from_pks ( RandomNumberGenerator & rng ) const

protectedinherited

Helper function for generate_another. Generate a new private key for each public key in this hybrid key.

Definition at line 45 of file hybrid_kem.cpp.

                                     {
   std::vector<std::unique_ptr<Private_Key>> new_private_keys;
   new_private_keys.reserve(public_keys().size());
   for(const auto& pk : public_keys()) {
      new_private_keys.push_back(pk->generate_another(rng));
   }
   return new_private_keys;
}

References public_keys().

Referenced by Botan::TLS::Hybrid_KEM_PublicKey::generate_another(), and Hybrid_PublicKey().

◆ 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.

TODO(Botan4) Change this to return by value

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 algo_name().

Referenced by estimated_strength(), 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 161 of file pk_keys.h.

161{ return this->object_identifier(); }

Botan::Asymmetric_Key::object_identifier

virtual OID object_identifier() const

Definition pk_keys.cpp:22

References get_oid(), and Botan::Asymmetric_Key::object_identifier().

Referenced by get_oid().

◆ key_length()

size_t Botan::Hybrid_PublicKey::key_length ( ) const

inlineoverridevirtualinherited

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 49 of file hybrid_kem.h.

49{ return m_key_length; }

◆ load_for_group()

std::unique_ptr< Hybrid_KEM_PublicKey > Botan::TLS::Hybrid_KEM_PublicKey::load_for_group	(	Group_Params	group,
		std::span< const uint8_t >	concatenated_public_values )

static

Definition at line 236 of file hybrid_public_key.cpp.

                                                                        {
   const auto public_key_lengths = public_key_lengths_for_group(group);
   auto alg_ids = algorithm_identifiers_for_group(group);
   BOTAN_ASSERT_NOMSG(public_key_lengths.size() == alg_ids.size());
 
   const auto expected_public_keys_length =
      reduce(public_key_lengths, size_t(0), [](size_t acc, size_t len) { return acc + len; });
   if(expected_public_keys_length != concatenated_public_keys.size()) {
      throw Decoding_Error("Concatenated public values have an unexpected length");
   }
 
   BufferSlicer public_key_slicer(concatenated_public_keys);
   std::vector<std::unique_ptr<Public_Key>> pks;
   pks.reserve(alg_ids.size());
   for(size_t idx = 0; idx < alg_ids.size(); ++idx) {
      pks.emplace_back(load_public_key(alg_ids[idx], public_key_slicer.take(public_key_lengths[idx])));
   }
   BOTAN_ASSERT_NOMSG(public_key_slicer.empty());
   return std::make_unique<Hybrid_KEM_PublicKey>(std::move(pks));
}

References BOTAN_ASSERT_NOMSG, Botan::BufferSlicer::empty(), load_for_group(), Botan::load_public_key(), Botan::reduce(), and Botan::BufferSlicer::take().

Referenced by load_for_group(), and Botan::TLS::Callbacks::tls_deserialize_peer_public_key().

◆ 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 221 of file pk_keys.h.

                                                                                     {
         return _signature_element_size_for_DER_encoding().value_or(0);
      }

References Botan::Asymmetric_Key::_signature_element_size_for_DER_encoding(), and message_part_size().

Referenced by message_part_size().

◆ 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 208 of file pk_keys.h.

                                                                                 {
         return _signature_element_size_for_DER_encoding() ? 2 : 1;
      }

References Botan::Asymmetric_Key::_signature_element_size_for_DER_encoding(), and message_parts().

Referenced by message_parts().

◆ 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::Classic_McEliece_PublicKey, 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 algo_name(), Botan::fmt(), and Botan::OID::from_string().

◆ public_key_bits()

std::vector< uint8_t > Botan::TLS::Hybrid_KEM_PublicKey::public_key_bits ( ) const

overridevirtual

Returns: BER encoded public key bits

Implements Botan::Public_Key.

Definition at line 281 of file hybrid_public_key.cpp.

                                                               {
   return raw_public_key_bits();
}

References raw_public_key_bits().

◆ public_keys()

const std::vector< std::unique_ptr< Public_Key > > & Botan::Hybrid_PublicKey::public_keys ( ) const

inlineinherited

Returns: the public keys combined in this hybrid key

Definition at line 66 of file hybrid_kem.h.

66{ return m_pks; }

Referenced by Botan::TLS::Hybrid_KEM_PublicKey::algo_name(), check_key(), Botan::TLS::Hybrid_KEM_PublicKey::create_kem_encryption_op(), generate_other_sks_from_pks(), raw_public_key_bits(), and Botan::TLS::Hybrid_KEM_PublicKey::raw_public_key_bits().

◆ raw_public_key_bits()

std::vector< uint8_t > Botan::TLS::Hybrid_KEM_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 285 of file hybrid_public_key.cpp.

                                                                   {
   // draft-ietf-tls-hybrid-design-06 3.2
   //   The values are directly concatenated, without any additional encoding
   //   or length fields; this assumes that the representation and length of
   //   elements is fixed once the algorithm is fixed.  If concatenation were
   //   to be used with values that are not fixed-length, a length prefix or
   //   other unambiguous encoding must be used to ensure that the composition
   //   of the two values is injective.
   return reduce(public_keys(), std::vector<uint8_t>(), [](auto pkb, const auto& key) {
      return concat(pkb, key->raw_public_key_bits());
   });
}

References Botan::concat(), Botan::Hybrid_PublicKey::public_keys(), and Botan::reduce().

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

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

◆ supports_operation()

bool Botan::Hybrid_PublicKey::supports_operation ( PublicKeyOperation op ) const

overridevirtualinherited

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

Implements Botan::Asymmetric_Key.

Definition at line 41 of file hybrid_kem.cpp.

                                                                     {
   return PublicKeyOperation::KeyEncapsulation == op;
}

References Botan::KeyEncapsulation.

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

src/lib/tls/tls13_pqc/hybrid_public_key.h
src/lib/tls/tls13_pqc/hybrid_public_key.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Hybrid_KEM_PublicKey() [1/2]

◆ Hybrid_KEM_PublicKey() [2/2]

Member Function Documentation

◆ _default_x509_signature_format()

◆ _signature_element_size_for_DER_encoding()

◆ algo_name()

◆ algorithm_identifier()

◆ check_key()

◆ create_encryption_op()

◆ create_kem_encryption_op()

◆ create_verification_op()

◆ create_x509_verification_op()

◆ default_x509_signature_format()

◆ estimated_strength()

◆ fingerprint_public()

◆ generate_another()

◆ generate_other_sks_from_pks()

◆ get_int_field()

◆ get_oid()

◆ key_length()

◆ load_for_group()

◆ message_part_size()

◆ message_parts()

◆ object_identifier()

◆ public_key_bits()

◆ public_keys()

◆ raw_public_key_bits()

◆ subject_public_key()

◆ supports_operation()