/*

* PK Operation Types

* (C) 2010,2015 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/internal/pk_ops_impl.h>

#include <botan/internal/bit_ops.h>

#include <botan/rng.h>

namespace Botan {

PK_Ops::Encryption_with_EME::Encryption_with_EME(const std::string& eme) :

   m_eme(EME::create(eme))

   {

   }

size_t PK_Ops::Encryption_with_EME::max_input_bits() const

   {

   return 8 * m_eme->maximum_input_size(max_raw_input_bits());

   }

secure_vector<uint8_t> PK_Ops::Encryption_with_EME::encrypt(const uint8_t msg[], size_t msg_len,

                                                         RandomNumberGenerator& rng)

   {

   const size_t max_raw = max_raw_input_bits();

   const std::vector<uint8_t> encoded = unlock(m_eme->encode(msg, msg_len, max_raw, rng));

   return raw_encrypt(encoded.data(), encoded.size(), rng);

   }

PK_Ops::Decryption_with_EME::Decryption_with_EME(const std::string& eme) :

   m_eme(EME::create(eme))

   {

   }

secure_vector<uint8_t>

PK_Ops::Decryption_with_EME::decrypt(uint8_t& valid_mask,

                                     const uint8_t ciphertext[],

                                     size_t ciphertext_len)

   {

   const secure_vector<uint8_t> raw = raw_decrypt(ciphertext, ciphertext_len);

   return m_eme->unpad(valid_mask, raw.data(), raw.size());

   }

PK_Ops::Key_Agreement_with_KDF::Key_Agreement_with_KDF(const std::string& kdf)

   {

   if(kdf != "Raw")

      m_kdf = KDF::create_or_throw(kdf);

   }

secure_vector<uint8_t> PK_Ops::Key_Agreement_with_KDF::agree(size_t key_len,

                                                          const uint8_t w[], size_t w_len,

                                                          const uint8_t salt[], size_t salt_len)

   {

   secure_vector<uint8_t> z = raw_agree(w, w_len);

   if(m_kdf)

      return m_kdf->derive_key(key_len, z, salt, salt_len);

   return z;

   }

PK_Ops::Signature_with_EMSA::Signature_with_EMSA(const std::string& emsa, bool with_message_recovery) :

   Signature(),

   m_emsa(EMSA::create_or_throw(emsa)),

   m_hash(hash_for_emsa(emsa)),

   m_prefix_used(false)

   {

   if(!with_message_recovery && m_emsa->requires_message_recovery())

      {

      throw Invalid_Argument("Signature padding method " + emsa +

                             " requires message recovery, which is not supported by this scheme");

      }

   }

void PK_Ops::Signature_with_EMSA::update(const uint8_t msg[], size_t msg_len)

   {

   if(has_prefix() && !m_prefix_used)

      {

      m_prefix_used = true;

      secure_vector<uint8_t> prefix = message_prefix();

      m_emsa->update(prefix.data(), prefix.size());

      }

   m_emsa->update(msg, msg_len);

   }

secure_vector<uint8_t> PK_Ops::Signature_with_EMSA::sign(RandomNumberGenerator& rng)

   {

   m_prefix_used = false;

   const secure_vector<uint8_t> msg = m_emsa->raw_data();

   const auto padded = m_emsa->encoding_of(msg, this->max_input_bits(), rng);

   return raw_sign(padded.data(), padded.size(), rng);

   }

PK_Ops::Verification_with_EMSA::Verification_with_EMSA(const std::string& emsa, bool with_message_recovery) :

   Verification(),

   m_emsa(EMSA::create_or_throw(emsa)),

   m_hash(hash_for_emsa(emsa)),

   m_prefix_used(false)

   {

   if(!with_message_recovery && m_emsa->requires_message_recovery())

      {

      throw Invalid_Argument("Signature padding method " + emsa +

                             " requires message recovery, which is not supported by this scheme");

      }

   }

void PK_Ops::Verification_with_EMSA::update(const uint8_t msg[], size_t msg_len)

   {

   if(has_prefix() && !m_prefix_used)

      {

      m_prefix_used = true;

      secure_vector<uint8_t> prefix = message_prefix();

      m_emsa->update(prefix.data(), prefix.size());

      }

   m_emsa->update(msg, msg_len);

   }

bool PK_Ops::Verification_with_EMSA::is_valid_signature(const uint8_t sig[], size_t sig_len)

   {

   m_prefix_used = false;

   const secure_vector<uint8_t> msg = m_emsa->raw_data();

   if(with_recovery())

      {

      secure_vector<uint8_t> output_of_key = verify_mr(sig, sig_len);

      return m_emsa->verify(output_of_key, msg, max_input_bits());

      }

   else

      {

      Null_RNG rng;

      secure_vector<uint8_t> encoded = m_emsa->encoding_of(msg, max_input_bits(), rng);

      return verify(encoded.data(), encoded.size(), sig, sig_len);

      }

   }

void PK_Ops::KEM_Encryption_with_KDF::kem_encrypt(secure_vector<uint8_t>& out_encapsulated_key,

                                                  secure_vector<uint8_t>& out_shared_key,

                                                  size_t desired_shared_key_len,

                                                  RandomNumberGenerator& rng,

                                                  const uint8_t salt[],

                                                  size_t salt_len)

   {

   secure_vector<uint8_t> raw_shared;

   this->raw_kem_encrypt(out_encapsulated_key, raw_shared, rng);

   out_shared_key = (m_kdf)

      ? m_kdf->derive_key(desired_shared_key_len,

                          raw_shared.data(), raw_shared.size(),

                          salt, salt_len)

      : raw_shared;

   }

PK_Ops::KEM_Encryption_with_KDF::KEM_Encryption_with_KDF(const std::string& kdf)

   {

   if(kdf != "Raw")

      m_kdf = KDF::create_or_throw(kdf);

   }

secure_vector<uint8_t>

PK_Ops::KEM_Decryption_with_KDF::kem_decrypt(const uint8_t encap_key[],

                                             size_t len,

                                             size_t desired_shared_key_len,

                                             const uint8_t salt[],

                                             size_t salt_len)

   {

   secure_vector<uint8_t> raw_shared = this->raw_kem_decrypt(encap_key, len);

   if(m_kdf)

      return m_kdf->derive_key(desired_shared_key_len,

                               raw_shared.data(), raw_shared.size(),

                               salt, salt_len);

   return raw_shared;

   }

PK_Ops::KEM_Decryption_with_KDF::KEM_Decryption_with_KDF(const std::string& kdf)

   {

   if(kdf != "Raw")

      m_kdf = KDF::create_or_throw(kdf);

   }

}