Botan::OAEP Class Reference

#include <oaep.h>

Inheritance diagram for Botan::OAEP:

Public Member Functions
size_t	maximum_input_size (size_t) const override
	OAEP (std::unique_ptr< HashFunction > hash, std::string_view P="")
	OAEP (std::unique_ptr< HashFunction > hash, std::unique_ptr< HashFunction > mgf1_hash, std::string_view P="")

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

Detailed Description

OAEP (called EME1 in IEEE 1363 and in earlier versions of the library) as specified in PKCS#1 v2.0 (RFC 2437) or PKCS#1 v2.1 (RFC 3447)

Definition at line 22 of file oaep.h.

Constructor & Destructor Documentation

OAEP() [1/2]

Botan::OAEP::OAEP	(	std::unique_ptr< HashFunction >	hash,
		std::string_view	P = "" )

Parameters

hash	function to use for hashing (takes ownership)
P	an optional label. Normally empty.

Definition at line 149 of file oaep.cpp.

                                                             : m_mgf1_hash(std::move(hash)) {
   m_Phash = m_mgf1_hash->process(P);
}

OAEP() [2/2]

Botan::OAEP::OAEP	(	std::unique_ptr< HashFunction >	hash,
		std::unique_ptr< HashFunction >	mgf1_hash,
		std::string_view	P = "" )

Parameters

hash	function to use for hashing (takes ownership)
mgf1_hash	function to use for MGF1 (takes ownership)
P	an optional label. Normally empty.

Definition at line 153 of file oaep.cpp.

                                                                                                    :
      m_mgf1_hash(std::move(mgf1_hash)) {
   auto phash = std::move(hash);
   m_Phash = phash->process(P);
}

Member Function Documentation

create()

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

staticinherited

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)
   // TODO(Botan4) Remove all but "PKCS1v15"
   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);
 
   // TODO(Botan4) Remove all but "OAEP"
   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()

size_t Botan::OAEP::maximum_input_size ( size_t keybits ) const

overridevirtual

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

Implements Botan::EME.

Definition at line 141 of file oaep.cpp.

                                                    {
   if(keybits / 8 > 2 * m_Phash.size() + 1) {
      return ((keybits / 8) - 2 * m_Phash.size() - 1);
   } else {
      return 0;
   }
}

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

• src/lib/pk_pad/eme_oaep/oaep.h
• src/lib/pk_pad/eme_oaep/oaep.cpp