/*
* OAEP
* (C) 1999-2007,2018 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_OAEP_H_
#define BOTAN_OAEP_H_

#include <botan/hash.h>
#include <botan/internal/eme.h>

namespace Botan {

/**
* 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)
*/
class OAEP final : public EME {
   public:
      size_t maximum_input_size(size_t) const override;

      /**
      * @param hash function to use for hashing (takes ownership)
      * @param P an optional label. Normally empty.
      */
      OAEP(std::unique_ptr<HashFunction> hash, std::string_view P = "");

      /**
      * @param hash function to use for hashing (takes ownership)
      * @param mgf1_hash function to use for MGF1 (takes ownership)
      * @param P an optional label. Normally empty.
      */
      OAEP(std::unique_ptr<HashFunction> hash, std::unique_ptr<HashFunction> mgf1_hash, std::string_view P = "");

   private:
      secure_vector<uint8_t> pad(const uint8_t in[],
                                 size_t in_length,
                                 size_t key_length,
                                 RandomNumberGenerator& rng) const override;

      secure_vector<uint8_t> unpad(uint8_t& valid_mask, const uint8_t in[], size_t in_len) const override;

      secure_vector<uint8_t> m_Phash;
      std::unique_ptr<HashFunction> m_mgf1_hash;
};

secure_vector<uint8_t> BOTAN_TEST_API oaep_find_delim(uint8_t& valid_mask,
                                                      const uint8_t input[],
                                                      size_t input_len,
                                                      const secure_vector<uint8_t>& Phash);

}  // namespace Botan

#endif
