/*
* PK Key Types
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_PK_KEYS_H_
#define BOTAN_PK_KEYS_H_

#include <botan/secmem.h>
#include <botan/asn1_obj.h>
#include <botan/pk_ops_fwd.h>
#include <string>

namespace Botan {

class RandomNumberGenerator;

/**
* The two types of signature format supported by Botan.
*/
enum Signature_Format { IEEE_1363, DER_SEQUENCE };

/**
* Public Key Base Class.
*/
class BOTAN_PUBLIC_API(2,0) Public_Key
   {
   public:
      Public_Key() =default;
      Public_Key(const Public_Key& other) = default;
      Public_Key& operator=(const Public_Key& other) = default;
      virtual ~Public_Key() = default;

      /**
      * Get the name of the underlying public key scheme.
      * @return name of the public key scheme
      */
      virtual std::string algo_name() const = 0;

      /**
      * Return the estimated strength of the underlying key against
      * the best currently known attack. Note that this ignores anything
      * but pure attacks against the key itself and do not take into
      * account padding schemes, usage mistakes, etc which might reduce
      * the strength. However it does suffice to provide an upper bound.
      *
      * @return estimated strength in bits
      */
      virtual size_t estimated_strength() const = 0;

      /**
      * Return an integer value best approximating the length of the
      * primary security parameter. For example for RSA this will be
      * the size of the modulus, for ECDSA the size of the ECC group,
      * and for McEliece the size of the code will be returned.
      */
      virtual size_t key_length() const = 0;

      /**
      * Get the OID of the underlying public key scheme.
      * @return OID of the public key scheme
      */
      virtual OID get_oid() const;

      /**
      * Test the key values for consistency.
      * @param rng rng to use
      * @param strong whether to perform strong and lengthy version
      * of the test
      * @return true if the test is passed
      */
      virtual bool check_key(RandomNumberGenerator& rng,
                             bool strong) const = 0;


      /**
      * @return X.509 AlgorithmIdentifier for this key
      */
      virtual AlgorithmIdentifier algorithm_identifier() const = 0;

      /**
      * @return BER encoded public key bits
      */
      virtual std::vector<uint8_t> public_key_bits() const = 0;

      /**
      * @return X.509 subject key encoding for this key object
      */
      std::vector<uint8_t> subject_public_key() const;

      /**
       * @return Hash of the subject public key
       */
      std::string fingerprint_public(const std::string& alg = "SHA-256") const;

      // Internal or non-public declarations follow

      /**
      * Returns more than 1 if the output of this algorithm
      * (ciphertext, signature) should be treated as more than one
      * value. This is used for algorithms like DSA and ECDSA, where
      * the (r,s) output pair can be encoded as either a plain binary
      * list or a TLV tagged DER encoding depending on the protocol.
      *
      * This function is public but applications should have few
      * reasons to ever call this.
      *
      * @return number of message parts
      */
      virtual size_t message_parts() const { return 1; }

      /**
      * Returns how large each of the message parts refered to
      * by message_parts() is
      *
      * This function is public but applications should have few
      * reasons to ever call this.
      *
      * @return size of the message parts in bits
      */
      virtual size_t message_part_size() const { return 0; }

      virtual Signature_Format default_x509_signature_format() const
         {
         return (this->message_parts() >= 2) ? DER_SEQUENCE : IEEE_1363;
         }

      /**
      * This is an internal library function exposed on key types.
      * In almost all cases applications should use wrappers in pubkey.h
      *
      * Return an encryption operation for this key/params or throw
      *
      * @param rng a random number generator. The PK_Op may maintain a
      * reference to the RNG and use it many times. The rng must outlive
      * any operations which reference it.
      * @param params additional parameters
      * @param provider the provider to use
      */
      virtual std::unique_ptr<PK_Ops::Encryption>
         create_encryption_op(RandomNumberGenerator& rng,
                              const std::string& params,
                              const std::string& provider) const;

      /**
      * This is an internal library function exposed on key types.
      * In almost all cases applications should use wrappers in pubkey.h
      *
      * Return a KEM encryption operation for this key/params or throw
      *
      * @param rng a random number generator. The PK_Op may maintain a
      * reference to the RNG and use it many times. The rng must outlive
      * any operations which reference it.
      * @param params additional parameters
      * @param provider the provider to use
      */
      virtual std::unique_ptr<PK_Ops::KEM_Encryption>
         create_kem_encryption_op(RandomNumberGenerator& rng,
                                  const std::string& params,
                                  const std::string& provider) const;

      /**
      * This is an internal library function exposed on key types.
      * In almost all cases applications should use wrappers in pubkey.h
      *
      * Return a verification operation for this key/params or throw
      * @param params additional parameters
      * @param provider the provider to use
      */
      virtual std::unique_ptr<PK_Ops::Verification>
         create_verification_op(const std::string& params,
                                const std::string& provider) const;
   };

/**
* Private Key Base Class
*/
class BOTAN_PUBLIC_API(2,0) Private_Key : public virtual Public_Key
   {
   public:
      Private_Key() = default;
      Private_Key(const Private_Key& other) = default;
      Private_Key& operator=(const Private_Key& other) = default;
      virtual ~Private_Key() = default;

      virtual bool stateful_operation() const { return false; }

      /**
      * @return BER encoded private key bits
      */
      virtual secure_vector<uint8_t> private_key_bits() const = 0;

      /**
      * @return PKCS #8 private key encoding for this key object
      */
      secure_vector<uint8_t> private_key_info() const;

      /**
      * @return PKCS #8 AlgorithmIdentifier for this key
      * Might be different from the X.509 identifier, but normally is not
      */
      virtual AlgorithmIdentifier pkcs8_algorithm_identifier() const
         { return algorithm_identifier(); }

      // Internal or non-public declarations follow

      /**
       * @return Hash of the PKCS #8 encoding for this key object
       */
      std::string fingerprint_private(const std::string& alg) const;

      BOTAN_DEPRECATED("Use fingerprint_private or fingerprint_public")
         inline std::string fingerprint(const std::string& alg) const
         {
         return fingerprint_private(alg); // match behavior in previous versions
         }

      /**
      * This is an internal library function exposed on key types.
      * In almost all cases applications should use wrappers in pubkey.h
      *
      * Return an decryption operation for this key/params or throw
      *
      * @param rng a random number generator. The PK_Op may maintain a
      * reference to the RNG and use it many times. The rng must outlive
      * any operations which reference it.
      * @param params additional parameters
      * @param provider the provider to use
      *
      */
      virtual std::unique_ptr<PK_Ops::Decryption>
         create_decryption_op(RandomNumberGenerator& rng,
                              const std::string& params,
                              const std::string& provider) const;

      /**
      * This is an internal library function exposed on key types.
      * In almost all cases applications should use wrappers in pubkey.h
      *
      * Return a KEM decryption operation for this key/params or throw
      *
      * @param rng a random number generator. The PK_Op may maintain a
      * reference to the RNG and use it many times. The rng must outlive
      * any operations which reference it.
      * @param params additional parameters
      * @param provider the provider to use
      */
      virtual std::unique_ptr<PK_Ops::KEM_Decryption>
         create_kem_decryption_op(RandomNumberGenerator& rng,
                                  const std::string& params,
                                  const std::string& provider) const;

      /**
      * This is an internal library function exposed on key types.
      * In almost all cases applications should use wrappers in pubkey.h
      *
      * Return a signature operation for this key/params or throw
      *
      * @param rng a random number generator. The PK_Op may maintain a
      * reference to the RNG and use it many times. The rng must outlive
      * any operations which reference it.
      * @param params additional parameters
      * @param provider the provider to use
      */
      virtual std::unique_ptr<PK_Ops::Signature>
         create_signature_op(RandomNumberGenerator& rng,
                             const std::string& params,
                             const std::string& provider) const;

      /**
      * This is an internal library function exposed on key types.
      * In almost all cases applications should use wrappers in pubkey.h
      *
      * Return a key agreement operation for this key/params or throw
      *
      * @param rng a random number generator. The PK_Op may maintain a
      * reference to the RNG and use it many times. The rng must outlive
      * any operations which reference it.
      * @param params additional parameters
      * @param provider the provider to use
      */
      virtual std::unique_ptr<PK_Ops::Key_Agreement>
         create_key_agreement_op(RandomNumberGenerator& rng,
                                 const std::string& params,
                                 const std::string& provider) const;
   };

/**
* PK Secret Value Derivation Key
*/
class BOTAN_PUBLIC_API(2,0) PK_Key_Agreement_Key : public virtual Private_Key
   {
   public:
      /*
      * @return public component of this key
      */
      virtual std::vector<uint8_t> public_value() const = 0;

      PK_Key_Agreement_Key() = default;
      PK_Key_Agreement_Key(const PK_Key_Agreement_Key&) = default;
      PK_Key_Agreement_Key& operator=(const PK_Key_Agreement_Key&) = default;
      virtual ~PK_Key_Agreement_Key() = default;
   };

/*
* Old compat typedefs
* TODO: remove these?
*/
typedef PK_Key_Agreement_Key PK_KA_Key;
typedef Public_Key X509_PublicKey;
typedef Private_Key PKCS8_PrivateKey;

std::string BOTAN_PUBLIC_API(2,4)
   create_hex_fingerprint(const uint8_t bits[], size_t len,
                          const std::string& hash_name);

template<typename Alloc>
std::string create_hex_fingerprint(const std::vector<uint8_t, Alloc>& vec,
                                   const std::string& hash_name)
   {
   return create_hex_fingerprint(vec.data(), vec.size(), hash_name);
   }


}

#endif