/**

* (C) 2018,2019 Jack Lloyd

*

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

*/

#ifndef BOTAN_ARGON2_H_

#define BOTAN_ARGON2_H_

#include <botan/pwdhash.h>

//BOTAN_FUTURE_INTERNAL_HEADER(argon2.h)

namespace Botan {

class RandomNumberGenerator;

/**

* Argon2 key derivation function

*/

class BOTAN_PUBLIC_API(2,11) Argon2 final : public PasswordHash

   {

   public:

      Argon2(uint8_t family, size_t M, size_t t, size_t p);

      Argon2(const Argon2& other) = default;

      Argon2& operator=(const Argon2&) = default;

      /**

      * Derive a new key under the current Argon2 parameter set

      */

      void derive_key(uint8_t out[], size_t out_len,

                      const char* password, size_t password_len,

                      const uint8_t salt[], size_t salt_len) const override;

      std::string to_string() const override;

      size_t M() const { return m_M; }

      size_t t() const { return m_t; }

      size_t p() const { return m_p; }

      size_t iterations() const override { return t(); }

      size_t parallelism() const override { return p(); }

      size_t memory_param() const override { return M(); }

      size_t total_memory_usage() const override { return M() * 1024; }

   private:

      uint8_t m_family;

      size_t m_M, m_t, m_p;

   };

class BOTAN_PUBLIC_API(2,11) Argon2_Family final : public PasswordHashFamily

   {

   public:

      Argon2_Family(uint8_t family);

      std::string name() const override;

      std::unique_ptr<PasswordHash> tune(size_t output_length,

                                         std::chrono::milliseconds msec,

                                         size_t max_memory) const override;

      std::unique_ptr<PasswordHash> default_params() const override;

      std::unique_ptr<PasswordHash> from_iterations(size_t iter) const override;

      std::unique_ptr<PasswordHash> from_params(

         size_t M, size_t t, size_t p) const override;

   private:

      const uint8_t m_family;

   };

/**

* Argon2 key derivation function

*

* @param output the output will be placed here

* @param output_len length of output

* @param password the user password

* @param password_len the length of password

* @param salt the salt

* @param salt_len length of salt

* @param key an optional secret key

* @param key_len the length of key

* @param ad an optional additional input

* @param ad_len the length of ad

* @param y the Argon2 variant (0 = Argon2d, 1 = Argon2i, 2 = Argon2id)

* @param p the parallelization parameter

* @param M the amount of memory to use in Kb

* @param t the number of iterations to use

*/

void BOTAN_PUBLIC_API(2,11) argon2(uint8_t output[], size_t output_len,

                                   const char* password, size_t password_len,

                                   const uint8_t salt[], size_t salt_len,

                                   const uint8_t key[], size_t key_len,

                                   const uint8_t ad[], size_t ad_len,

                                   uint8_t y, size_t p, size_t M, size_t t);

std::string BOTAN_PUBLIC_API(2,11)

   argon2_generate_pwhash(const char* password, size_t password_len,

                          RandomNumberGenerator& rng,

                          size_t p, size_t M, size_t t,

                          uint8_t y = 2, size_t salt_len = 16, size_t output_len = 32);

/**

* Check a previously created password hash

* @param password the password to check against

* @param password_len the length of password

* @param hash the stored hash to check against

*/

bool BOTAN_PUBLIC_API(2,11) argon2_check_pwhash(const char* password, size_t password_len,

                                                const std::string& hash);

}

#endif