1 // Copyright 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef SYNC_UTIL_NIGORI_H_ 6 #define SYNC_UTIL_NIGORI_H_ 7 8 #include <string> 9 10 #include "base/memory/scoped_ptr.h" 11 #include "sync/base/sync_export.h" 12 13 namespace crypto { 14 class SymmetricKey; 15 } // namespace crypto 16 17 namespace syncer { 18 19 // A (partial) implementation of Nigori, a protocol to securely store secrets in 20 // the cloud. This implementation does not support server authentication or 21 // assisted key derivation. 22 // 23 // To store secrets securely, use the |Permute| method to derive a lookup name 24 // for your secret (basically a map key), and |Encrypt| and |Decrypt| to store 25 // and retrieve the secret. 26 // 27 // TODO: Link to doc. 28 class SYNC_EXPORT Nigori { 29 public: 30 enum Type { 31 Password = 1, 32 }; 33 34 Nigori(); 35 virtual ~Nigori(); 36 37 // Initialize the client with the given |hostname|, |username| and |password|. 38 bool InitByDerivation(const std::string& hostname, 39 const std::string& username, 40 const std::string& password); 41 42 // Initialize the client by importing the given keys instead of deriving new 43 // ones. 44 bool InitByImport(const std::string& user_key, 45 const std::string& encryption_key, 46 const std::string& mac_key); 47 48 // Derives a secure lookup name from |type| and |name|. If |hostname|, 49 // |username| and |password| are kept constant, a given |type| and |name| pair 50 // always yields the same |permuted| value. Note that |permuted| will be 51 // Base64 encoded. 52 bool Permute(Type type, const std::string& name, std::string* permuted) const; 53 54 // Encrypts |value|. Note that on success, |encrypted| will be Base64 55 // encoded. 56 bool Encrypt(const std::string& value, std::string* encrypted) const; 57 58 // Decrypts |value| into |decrypted|. It is assumed that |value| is Base64 59 // encoded. 60 bool Decrypt(const std::string& value, std::string* decrypted) const; 61 62 // Exports the raw derived keys. 63 bool ExportKeys(std::string* user_key, 64 std::string* encryption_key, 65 std::string* mac_key) const; 66 67 static const char kSaltSalt[]; // The salt used to derive the user salt. 68 static const size_t kSaltKeySizeInBits = 128; 69 static const size_t kDerivedKeySizeInBits = 128; 70 static const size_t kIvSize = 16; 71 static const size_t kHashSize = 32; 72 73 static const size_t kSaltIterations = 1001; 74 static const size_t kUserIterations = 1002; 75 static const size_t kEncryptionIterations = 1003; 76 static const size_t kSigningIterations = 1004; 77 78 private: 79 scoped_ptr<crypto::SymmetricKey> user_key_; 80 scoped_ptr<crypto::SymmetricKey> encryption_key_; 81 scoped_ptr<crypto::SymmetricKey> mac_key_; 82 }; 83 84 } // namespace syncer 85 86 #endif // SYNC_UTIL_NIGORI_H_ 87