eme.cpp

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/*
* EME Base Class
* (C) 1999-2008 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#include <botan/internal/eme.h>
 
#include <botan/exceptn.h>
#include <botan/internal/parsing.h>
#include <botan/internal/scan_name.h>
 
#if defined(BOTAN_HAS_EME_OAEP)
   #include <botan/internal/oaep.h>
#endif
 
#if defined(BOTAN_HAS_EME_PKCS1)
   #include <botan/internal/eme_pkcs.h>
#endif
 
#if defined(BOTAN_HAS_EME_RAW)
   #include <botan/internal/eme_raw.h>
#endif
 
namespace Botan {
 
std::unique_ptr<EME> EME::create(std::string_view algo_spec) {
#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);
}
 
/*
* Encode a message
*/
secure_vector<uint8_t> EME::encode(const uint8_t msg[],
                                   size_t msg_len,
                                   size_t key_bits,
                                   RandomNumberGenerator& rng) const {
   return pad(msg, msg_len, key_bits, rng);
}
 
/*
* Encode a message
*/
secure_vector<uint8_t> EME::encode(const secure_vector<uint8_t>& msg,
                                   size_t key_bits,
                                   RandomNumberGenerator& rng) const {
   return pad(msg.data(), msg.size(), key_bits, rng);
}
 
}  // namespace Botan