// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_WEBCRYPTO_ALGORITHM_IMPLEMENTATION_H_
#define COMPONENTS_WEBCRYPTO_ALGORITHM_IMPLEMENTATION_H_

#include <stdint.h>
#include <vector>

#include "base/memory/scoped_ptr.h"
#include "third_party/WebKit/public/platform/WebCrypto.h"

namespace webcrypto {

class CryptoData;
class GenerateKeyResult;
class Status;

// AlgorithmImplementation is a base class for *executing* the operations of an
// algorithm (generating keys, encrypting, signing, etc.).
//
// This is in contrast to blink::WebCryptoAlgorithm which instead *describes*
// the operation and its parameters.
//
// AlgorithmImplementation has reasonable default implementations for all
// methods which behave as if the operation is it is unsupported, so
// implementations need only override the applicable methods.
//
// Unless stated otherwise methods of AlgorithmImplementation are responsible
// for sanitizing their inputs. The following can be assumed:
//
//   * |algorithm.id()| and |key.algorithm.id()| matches the algorithm under
//     which the implementation was registerd.
//   * |algorithm| has the correct parameters type for the operation.
//   * The key usages have already been verified. In fact in the case of calls
//     to Encrypt()/Decrypt() the corresponding key usages may not be present
//     (when wrapping/unwrapping).
//
// An AlgorithmImplementation can also assume that
// crypto::EnsureOpenSSLInit() will be called before any of its
// methods are invoked (except the constructor).
class AlgorithmImplementation {
 public:
  virtual ~AlgorithmImplementation();

  // This method corresponds to Web Crypto's crypto.subtle.encrypt().
  virtual Status Encrypt(const blink::WebCryptoAlgorithm& algorithm,
                         const blink::WebCryptoKey& key,
                         const CryptoData& data,
                         std::vector<uint8_t>* buffer) const;

  // This method corresponds to Web Crypto's crypto.subtle.decrypt().
  virtual Status Decrypt(const blink::WebCryptoAlgorithm& algorithm,
                         const blink::WebCryptoKey& key,
                         const CryptoData& data,
                         std::vector<uint8_t>* buffer) const;

  // This method corresponds to Web Crypto's crypto.subtle.sign().
  virtual Status Sign(const blink::WebCryptoAlgorithm& algorithm,
                      const blink::WebCryptoKey& key,
                      const CryptoData& data,
                      std::vector<uint8_t>* buffer) const;

  // This method corresponds to Web Crypto's crypto.subtle.verify().
  virtual Status Verify(const blink::WebCryptoAlgorithm& algorithm,
                        const blink::WebCryptoKey& key,
                        const CryptoData& signature,
                        const CryptoData& data,
                        bool* signature_match) const;

  // This method corresponds to Web Crypto's crypto.subtle.digest().
  virtual Status Digest(const blink::WebCryptoAlgorithm& algorithm,
                        const CryptoData& data,
                        std::vector<uint8_t>* buffer) const;

  // This method corresponds to Web Crypto's crypto.subtle.generateKey().
  //
  // Implementations MUST verify |usages| and return an error if it is not
  // appropriate.
  virtual Status GenerateKey(const blink::WebCryptoAlgorithm& algorithm,
                             bool extractable,
                             blink::WebCryptoKeyUsageMask usages,
                             GenerateKeyResult* result) const;

  // This method corresponds to Web Crypto's "derive bits" operation. It is
  // essentially crypto.subtle.deriveBits() with the exception that the length
  // can be "null" (|has_length_bits = true|).
  //
  // In cases where the length was not specified, an appropriate default for the
  // algorithm should be used (as described by the spec).
  virtual Status DeriveBits(const blink::WebCryptoAlgorithm& algorithm,
                            const blink::WebCryptoKey& base_key,
                            bool has_optional_length_bits,
                            unsigned int optional_length_bits,
                            std::vector<uint8_t>* derived_bytes) const;

  // This method corresponds with Web Crypto's "Get key length" operation.
  //
  // In the Web Crypto spec the operation returns either "null" or an
  // "Integer". In this code "null" is represented by setting
  // |*has_length_bits = false|.
  virtual Status GetKeyLength(
      const blink::WebCryptoAlgorithm& key_length_algorithm,
      bool* has_length_bits,
      unsigned int* length_bits) const;

  // -----------------------------------------------
  // Key import
  // -----------------------------------------------

  // VerifyKeyUsagesBeforeImportKey() must be called before either
  // importing a key, or unwrapping a key.
  //
  // Implementations should return an error if the requested usages are invalid
  // when importing for the specified format.
  //
  // For instance, importing an RSA-SSA key with 'spki' format and Sign usage
  // is invalid. The 'spki' format implies it will be a public key, and public
  // keys do not support signing.
  //
  // When called with format=JWK the key type may be unknown. The
  // ImportKeyJwk() must do the final usage check.
  virtual Status VerifyKeyUsagesBeforeImportKey(
      blink::WebCryptoKeyFormat format,
      blink::WebCryptoKeyUsageMask usages) const;

  // Dispatches to the format-specific ImportKey* method.
  Status ImportKey(blink::WebCryptoKeyFormat format,
                   const CryptoData& key_data,
                   const blink::WebCryptoAlgorithm& algorithm,
                   bool extractable,
                   blink::WebCryptoKeyUsageMask usages,
                   blink::WebCryptoKey* key) const;

  // This method corresponds to Web Crypto's
  // crypto.subtle.importKey(format='raw').
  virtual Status ImportKeyRaw(const CryptoData& key_data,
                              const blink::WebCryptoAlgorithm& algorithm,
                              bool extractable,
                              blink::WebCryptoKeyUsageMask usages,
                              blink::WebCryptoKey* key) const;

  // This method corresponds to Web Crypto's
  // crypto.subtle.importKey(format='pkcs8').
  virtual Status ImportKeyPkcs8(const CryptoData& key_data,
                                const blink::WebCryptoAlgorithm& algorithm,
                                bool extractable,
                                blink::WebCryptoKeyUsageMask usages,
                                blink::WebCryptoKey* key) const;

  // This method corresponds to Web Crypto's
  // crypto.subtle.importKey(format='spki').
  virtual Status ImportKeySpki(const CryptoData& key_data,
                               const blink::WebCryptoAlgorithm& algorithm,
                               bool extractable,
                               blink::WebCryptoKeyUsageMask usages,
                               blink::WebCryptoKey* key) const;

  // This method corresponds to Web Crypto's
  // crypto.subtle.importKey(format='jwk').
  virtual Status ImportKeyJwk(const CryptoData& key_data,
                              const blink::WebCryptoAlgorithm& algorithm,
                              bool extractable,
                              blink::WebCryptoKeyUsageMask usages,
                              blink::WebCryptoKey* key) const;

  // -----------------------------------------------
  // Key export
  // -----------------------------------------------

  // Dispatches to the format-specific ExportKey* method.
  Status ExportKey(blink::WebCryptoKeyFormat format,
                   const blink::WebCryptoKey& key,
                   std::vector<uint8_t>* buffer) const;

  virtual Status ExportKeyRaw(const blink::WebCryptoKey& key,
                              std::vector<uint8_t>* buffer) const;

  virtual Status ExportKeyPkcs8(const blink::WebCryptoKey& key,
                                std::vector<uint8_t>* buffer) const;

  virtual Status ExportKeySpki(const blink::WebCryptoKey& key,
                               std::vector<uint8_t>* buffer) const;

  virtual Status ExportKeyJwk(const blink::WebCryptoKey& key,
                              std::vector<uint8_t>* buffer) const;

  // -----------------------------------------------
  // Structured clone
  // -----------------------------------------------

  // The Structured clone methods are used for synchronous serialization /
  // deserialization of a WebCryptoKey.
  //
  // This serialized format is used by Blink to:
  //   * Copy WebCryptoKeys between threads (postMessage to WebWorkers)
  //   * Copy WebCryptoKeys between domains (postMessage)
  //   * Copy WebCryptoKeys within the same domain (postMessage)
  //   * Persist the key to storage (IndexedDB)
  //
  // Implementations of structured cloning must:
  //   * Be threadsafe (structured cloning is called directly on the Blink
  //     thread, in contrast to the other methods of AlgorithmImplementation).
  //   * Use a stable format (a serialized key must forever be de-serializable,
  //     and be able to survive future migrations to crypto libraries)
  //   * Work for all keys (including ones marked as non-extractable).
  //
  // Tests to verify structured cloning are available in:
  //   LayoutTests/crypto/clone-*.html

  // Note that SerializeKeyForClone() is not virtual because all
  // implementations end up doing the same thing.
  Status SerializeKeyForClone(const blink::WebCryptoKey& key,
                              blink::WebVector<uint8_t>* key_data) const;

  virtual Status DeserializeKeyForClone(
      const blink::WebCryptoKeyAlgorithm& algorithm,
      blink::WebCryptoKeyType type,
      bool extractable,
      blink::WebCryptoKeyUsageMask usages,
      const CryptoData& key_data,
      blink::WebCryptoKey* key) const;
};

}  // namespace webcrypto

#endif  // COMPONENTS_WEBCRYPTO_ALGORITHM_IMPLEMENTATION_H_