Simplify AuthenticationMethod type and PIN hash handling.

remoting/protocol/authentication_method.h

Index: remoting/protocol/authentication_method.h
diff --git a/remoting/protocol/authentication_method.h b/remoting/protocol/authentication_method.h
index c2265d5e7d38e1b42138efbaf40203d61b453790..1b8dc46bddf5b09f0b09925e3bf31f56334e9f1c 100644
--- a/remoting/protocol/authentication_method.h
+++ b/remoting/protocol/authentication_method.h
@@ -1,14 +1,6 @@
 // Copyright (c) 2012 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.
-
-// AuthenticationMethod represents an authentication algorithm and its
-// configuration. It knows how to parse and format authentication
-// method names.
-// Currently the following methods are supported:
-//   spake2_plain - SPAKE2 without hashing applied to the password.
-//   spake2_hmac - SPAKE2 with HMAC hashing of the password.
-
 #ifndef REMOTING_PROTOCOL_AUTHENTICATION_METHOD_H_
 #define REMOTING_PROTOCOL_AUTHENTICATION_METHOD_H_
 
@@ -19,73 +11,37 @@ namespace protocol {
 
 class Authenticator;
 
-class AuthenticationMethod {
- public:
-  enum MethodType {
-    INVALID,
-    SPAKE2,
-    SPAKE2_PAIR,
-    THIRD_PARTY
-  };
-
-  enum HashFunction {
-    NONE,
-    HMAC_SHA256,
-  };
-
-  // Constructors for various authentication methods.
-  static AuthenticationMethod Invalid();
-  static AuthenticationMethod Spake2(HashFunction hash_function);
-  static AuthenticationMethod Spake2Pair();
-  static AuthenticationMethod ThirdParty();
-
-  // Parses a string that defines an authentication method. Returns an
-  // invalid value if the string is invalid.
-  static AuthenticationMethod FromString(const std::string& value);
-
-  // Applies the specified hash function to |shared_secret| with the
-  // specified |tag| as a key.
-  static std::string ApplyHashFunction(HashFunction hash_function,
-                                       const std::string& tag,
-                                       const std::string& shared_secret);
-
-  bool is_valid() const { return type_ != INVALID; }
-
-  MethodType type() const { return type_; }
-
-  // Following methods are valid only when is_valid() returns true.
-
-  // Hash function applied to the shared secret on both ends.
-  HashFunction hash_function() const;
-
-  // Returns string representation of the value stored in this object.
-  const std::string ToString() const;
+// AuthenticationMethod represents an authentication algorithm.
+enum class AuthenticationMethod {
+  INVALID,
+  SPAKE2_SHARED_SECRET_PLAIN,
+  SPAKE2_SHARED_SECRET_HMAC,
+  SPAKE2_PAIR,
+  THIRD_PARTY
+};
 
-  // Comparison operators so that std::find() can be used with
-  // collections of this class.
-  bool operator ==(const AuthenticationMethod& other) const;
-  bool operator !=(const AuthenticationMethod& other) const {
-    return !(*this == other);
-  }
+enum class HashFunction {
+  NONE,
+  HMAC_SHA256,
+};
 
- protected:
-  AuthenticationMethod();
-  AuthenticationMethod(MethodType type, HashFunction hash_function);
+// Parses a string that defines an authentication method. Returns
+// AuthenticationMethod::INVALID if the string is invalid.
+AuthenticationMethod ParseAuthenticationMethodString(const std::string& value);
 
-  MethodType type_;
-  HashFunction hash_function_;
-};
+// Returns string representation of |method|.
+const std::string AuthenticationMethodToString(AuthenticationMethod method);
 
-// SharedSecretHash stores hash of a host secret paired with the type
-// of the hashing function.
-struct SharedSecretHash {
-  AuthenticationMethod::HashFunction hash_function;
-  std::string value;
+// Returns hash function applied to the shared secret on both ends for the
+// spefied |method|.
+HashFunction GetHashFunctionForAuthenticationMethod(
+    AuthenticationMethod method);
 
-  // Parse string representation of a shared secret hash. The |as_string|
-  // must be in form "<hash_function>:<hash_value_base64>".
-  bool Parse(const std::string& as_string);
-};
+// Applies the specified hash function to |shared_secret| with the
+// specified |tag| as a key.
+std::string ApplySharedSecretHashFunction(HashFunction hash_function,
+                                          const std::string& tag,
+                                          const std::string& shared_secret);
 
 }  // namespace protocol
 }  // namespace remoting