Botan::EME Class Reference

#include <eme.h>

Inheritance diagram for Botan::EME:

Public Member Functions
virtual size_t	maximum_input_size (size_t keybits) const =0
virtual size_t	pad (std::span< uint8_t > output, std::span< const uint8_t > input, size_t key_length, RandomNumberGenerator &rng) const =0
virtual CT::Option< size_t >	unpad (std::span< uint8_t > output, std::span< const uint8_t > input) const =0
virtual	~EME ()

Static Public Member Functions
static std::unique_ptr< EME >	create (std::string_view algo_spec)

Detailed Description

Encoding Method for Encryption

Definition at line 23 of file eme.h.

Constructor & Destructor Documentation

~EME()

Botan::EME::~EME ( )

virtualdefault

Member Function Documentation

create()

std::unique_ptr< EME > Botan::EME::create ( std::string_view algo_spec )

static

Factory method for EME (message-encoding methods for encryption) objects

Parameters

algo_spec

the name of the EME to create

Returns

pointer to newly allocated object of that type

Definition at line 28 of file eme.cpp.

                                                       {
#if defined(BOTAN_HAS_EME_RAW)
   if(algo_spec == "Raw") {
      return std::make_unique<EME_Raw>();
   }
#endif
 
#if defined(BOTAN_HAS_EME_PKCS1)
   if(algo_spec == "PKCS1v15" || algo_spec == "EME-PKCS1-v1_5") {
      return std::make_unique<EME_PKCS1v15>();
   }
#endif
 
#if defined(BOTAN_HAS_EME_OAEP)
   SCAN_Name req(algo_spec);
 
   if(req.algo_name() == "OAEP" || req.algo_name() == "EME-OAEP" || req.algo_name() == "EME1") {
      if(req.arg_count() == 1 || ((req.arg_count() == 2 || req.arg_count() == 3) && req.arg(1) == "MGF1")) {
         if(auto hash = HashFunction::create(req.arg(0))) {
            return std::make_unique<OAEP>(std::move(hash), req.arg(2, ""));
         }
      } else if(req.arg_count() == 2 || req.arg_count() == 3) {
         auto mgf_params = parse_algorithm_name(req.arg(1));
 
         if(mgf_params.size() == 2 && mgf_params[0] == "MGF1") {
            auto hash = HashFunction::create(req.arg(0));
            auto mgf1_hash = HashFunction::create(mgf_params[1]);
 
            if(hash && mgf1_hash) {
               return std::make_unique<OAEP>(std::move(hash), std::move(mgf1_hash), req.arg(2, ""));
            }
         }
      }
   }
#endif
 
   throw Algorithm_Not_Found(algo_spec);
}

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_count(), Botan::HashFunction::create(), and Botan::parse_algorithm_name().

maximum_input_size()

virtual size_t Botan::EME::maximum_input_size ( size_t keybits ) const

pure virtual

Return the maximum input size in bytes we can support

Parameters

keybits

the size of the key in bits

Returns

upper bound of input in bytes

Implemented in Botan::OAEP.

pad()

virtual size_t Botan::EME::pad ( std::span< uint8_t > output, std::span< const uint8_t > input, size_t key_length, RandomNumberGenerator & rng ) const

pure virtual

Encode an input

Parameters

output	buffer that is written to
input	the plaintext
key_length	length of the key in bits
rng	a random number generator

Returns

number of bytes written to output

unpad()

virtual CT::Option< size_t > Botan::EME::unpad ( std::span< uint8_t > output, std::span< const uint8_t > input ) const

pure virtual

Decode an input

Parameters

output	buffer where output is placed
input	the encoded plaintext

Returns

number of bytes written to output if valid, or an empty option if invalid. If an empty option is returned the contents of output are undefined

---

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

• src/lib/pk_pad/eme.h
• src/lib/pk_pad/eme.cpp