Botan::PK_KEM_Decryptor Class Reference

#include <pubkey.h>

Public Member Functions
secure_vector< uint8_t >	decrypt (const uint8_t encap_key[], size_t encap_key_len, size_t desired_shared_key_len, const uint8_t salt[]=nullptr, size_t salt_len=0)
secure_vector< uint8_t >	decrypt (std::span< const uint8_t > encap_key, size_t desired_shared_key_len=32, std::span< const uint8_t > salt={})
void	decrypt (std::span< uint8_t > out_shared_key, std::span< const uint8_t > encap_key, size_t desired_shared_key_len=32, std::span< const uint8_t > salt={})
size_t	encapsulated_key_length () const
PK_KEM_Decryptor &	operator= (const PK_KEM_Decryptor &)=delete
PK_KEM_Decryptor &	operator= (PK_KEM_Decryptor &&) noexcept
	PK_KEM_Decryptor (const PK_KEM_Decryptor &)=delete
	PK_KEM_Decryptor (const Private_Key &key, RandomNumberGenerator &rng, std::string_view kem_param="", std::string_view provider="")
	PK_KEM_Decryptor (PK_KEM_Decryptor &&) noexcept
size_t	shared_key_length (size_t desired_shared_key_len) const
	~PK_KEM_Decryptor ()

Detailed Description

Public Key Key Encapsulation Mechanism Decryption.

Definition at line 724 of file pubkey.h.

Constructor & Destructor Documentation

PK_KEM_Decryptor() [1/3]

Botan::PK_KEM_Decryptor::PK_KEM_Decryptor	(	const Private_Key &	key,
		RandomNumberGenerator &	rng,
		std::string_view	kem_param = "",
		std::string_view	provider = "" )

Construct an instance.

Parameters

key	the key to use inside the decryptor
rng	the RNG to use
kem_param	additional KEM parameters
provider	the provider to use

Definition at line 176 of file pubkey.cpp.

                                                            {
   m_op = key.create_kem_decryption_op(rng, param, provider);
   if(!m_op) {
      throw Invalid_Argument(fmt("Key type {} does not support KEM decryption", key.algo_name()));
   }
}

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

~PK_KEM_Decryptor()

Botan::PK_KEM_Decryptor::~PK_KEM_Decryptor ( )

default

PK_KEM_Decryptor() [2/3]

Botan::PK_KEM_Decryptor::PK_KEM_Decryptor ( const PK_KEM_Decryptor & )

delete

PK_KEM_Decryptor() [3/3]

Botan::PK_KEM_Decryptor::PK_KEM_Decryptor ( PK_KEM_Decryptor && )

defaultnoexcept

Member Function Documentation

decrypt() [1/3]

secure_vector< uint8_t > Botan::PK_KEM_Decryptor::decrypt ( const uint8_t encap_key[], size_t encap_key_len, size_t desired_shared_key_len, const uint8_t salt[] = nullptr, size_t salt_len = 0 )

inline

Decrypts the shared key for data encryption.

Parameters

encap_key	the encapsulated key
encap_key_len	size of the encapsulated key in bytes
desired_shared_key_len	desired size of the shared key in bytes (ignored if no KDF is used)
salt	a salt value used in the KDF (ignored if no KDF is used)
salt_len	size of the salt value in bytes (ignored if no KDF is used)

Returns

the shared data encryption key

Definition at line 795 of file pubkey.h.

                                                          {
         secure_vector<uint8_t> shared_key(shared_key_length(desired_shared_key_len));
         decrypt(shared_key, {encap_key, encap_key_len}, desired_shared_key_len, {salt, salt_len});
         return shared_key;
      }

decrypt() [2/3]

secure_vector< uint8_t > Botan::PK_KEM_Decryptor::decrypt ( std::span< const uint8_t > encap_key, size_t desired_shared_key_len = 32, std::span< const uint8_t > salt = {} )

inline

Decrypts the shared key for data encryption.

Parameters

encap_key	the encapsulated key
desired_shared_key_len	desired size of the shared key in bytes (ignored if no KDF is used)
salt	a salt value used in the KDF (ignored if no KDF is used)

Returns

the shared data encryption key

Definition at line 816 of file pubkey.h.

                                                                   {}) {
         secure_vector<uint8_t> shared_key(shared_key_length(desired_shared_key_len));
         decrypt(shared_key, encap_key, desired_shared_key_len, salt);
         return shared_key;
      }

decrypt() [3/3]

void Botan::PK_KEM_Decryptor::decrypt	(	std::span< uint8_t >	out_shared_key,
		std::span< const uint8_t >	encap_key,
		size_t	desired_shared_key_len = 32,
		std::span< const uint8_t >	salt = {} )

Decrypts the shared key for data encryption.

Parameters

out_shared_key	the generated shared key
encap_key	the encapsulated key
desired_shared_key_len	desired size of the shared key in bytes (ignored if no KDF is used)
salt	a salt value used in the KDF (ignored if no KDF is used)

Definition at line 191 of file pubkey.cpp.

                                                            {
   BOTAN_ARG_CHECK(out_shared_key.size() == shared_key_length(desired_shared_key_len),
                   "inconsistent size of shared key output buffer");
   m_op->kem_decrypt(out_shared_key, encap_key, desired_shared_key_len, salt);
}

References BOTAN_ARG_CHECK.

Referenced by Botan::Kyber_PrivateKey::check_key(), and Botan::TLS::Callbacks::tls_kem_decapsulate().

encapsulated_key_length()

size_t Botan::PK_KEM_Decryptor::encapsulated_key_length

(

)

const

Return the length of the encapsulated key expected by this KEM

Definition at line 172 of file pubkey.cpp.

                                                       {
   return m_op->encapsulated_key_length();
}

Referenced by Botan::TLS::Callbacks::tls_kem_decapsulate().

operator=() [1/2]

PK_KEM_Decryptor & Botan::PK_KEM_Decryptor::operator= ( const PK_KEM_Decryptor & )

delete

operator=() [2/2]

PK_KEM_Decryptor & Botan::PK_KEM_Decryptor::operator= ( PK_KEM_Decryptor && )

defaultnoexcept

shared_key_length()

size_t Botan::PK_KEM_Decryptor::shared_key_length

(

size_t

desired_shared_key_len

)

const

Return the length of the shared key returned by this KEM

If this KEM was used with a KDF, then it will always return exactly the desired key length, because the output of the KEM will be hashed by the KDF.

However if the KEM was used with "Raw" kdf, to request the algorithmic output of the KEM directly, then the desired key length will be ignored and a bytestring that depends on the algorithm is returned

Parameters

desired_shared_key_len

is the requested length.

Definition at line 168 of file pubkey.cpp.

                                                                              {
   return m_op->shared_key_length(desired_shared_key_len);
}

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

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