Daniel Erat | 59c5f4b | 2015-08-24 12:50:25 -0600 | [diff] [blame^] | 1 | // Copyright (c) 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 CRYPTO_SYMMETRIC_KEY_H_ |
| 6 | #define CRYPTO_SYMMETRIC_KEY_H_ |
| 7 | |
| 8 | #include <string> |
| 9 | |
| 10 | #include "base/basictypes.h" |
| 11 | #include "crypto/crypto_export.h" |
| 12 | |
| 13 | #if defined(NACL_WIN64) |
| 14 | // See comments for crypto_nacl_win64 in crypto.gyp. |
| 15 | // Must test for NACL_WIN64 before OS_WIN since former is a subset of latter. |
| 16 | #include "crypto/scoped_capi_types.h" |
| 17 | #elif defined(USE_NSS_CERTS) || \ |
| 18 | (!defined(USE_OPENSSL) && (defined(OS_WIN) || defined(OS_MACOSX))) |
| 19 | #include "crypto/scoped_nss_types.h" |
| 20 | #endif |
| 21 | |
| 22 | namespace crypto { |
| 23 | |
| 24 | // Wraps a platform-specific symmetric key and allows it to be held in a |
| 25 | // scoped_ptr. |
| 26 | class CRYPTO_EXPORT SymmetricKey { |
| 27 | public: |
| 28 | // Defines the algorithm that a key will be used with. See also |
| 29 | // classs Encrptor. |
| 30 | enum Algorithm { |
| 31 | AES, |
| 32 | HMAC_SHA1, |
| 33 | }; |
| 34 | |
| 35 | virtual ~SymmetricKey(); |
| 36 | |
| 37 | // Generates a random key suitable to be used with |algorithm| and of |
| 38 | // |key_size_in_bits| bits. |key_size_in_bits| must be a multiple of 8. |
| 39 | // The caller is responsible for deleting the returned SymmetricKey. |
| 40 | static SymmetricKey* GenerateRandomKey(Algorithm algorithm, |
| 41 | size_t key_size_in_bits); |
| 42 | |
| 43 | // Derives a key from the supplied password and salt using PBKDF2, suitable |
| 44 | // for use with specified |algorithm|. Note |algorithm| is not the algorithm |
| 45 | // used to derive the key from the password. |key_size_in_bits| must be a |
| 46 | // multiple of 8. The caller is responsible for deleting the returned |
| 47 | // SymmetricKey. |
| 48 | static SymmetricKey* DeriveKeyFromPassword(Algorithm algorithm, |
| 49 | const std::string& password, |
| 50 | const std::string& salt, |
| 51 | size_t iterations, |
| 52 | size_t key_size_in_bits); |
| 53 | |
| 54 | // Imports an array of key bytes in |raw_key|. This key may have been |
| 55 | // generated by GenerateRandomKey or DeriveKeyFromPassword and exported with |
| 56 | // GetRawKey, or via another compatible method. The key must be of suitable |
| 57 | // size for use with |algorithm|. The caller owns the returned SymmetricKey. |
| 58 | static SymmetricKey* Import(Algorithm algorithm, const std::string& raw_key); |
| 59 | |
| 60 | #if defined(NACL_WIN64) |
| 61 | HCRYPTKEY key() const { return key_.get(); } |
| 62 | #elif defined(USE_OPENSSL) |
| 63 | const std::string& key() { return key_; } |
| 64 | #elif defined(USE_NSS_CERTS) || defined(OS_WIN) || defined(OS_MACOSX) |
| 65 | PK11SymKey* key() const { return key_.get(); } |
| 66 | #endif |
| 67 | |
| 68 | // Extracts the raw key from the platform specific data. |
| 69 | // Warning: |raw_key| holds the raw key as bytes and thus must be handled |
| 70 | // carefully. |
| 71 | bool GetRawKey(std::string* raw_key); |
| 72 | |
| 73 | private: |
| 74 | #if defined(NACL_WIN64) |
| 75 | SymmetricKey(HCRYPTPROV provider, HCRYPTKEY key, |
| 76 | const void* key_data, size_t key_size_in_bytes); |
| 77 | |
| 78 | ScopedHCRYPTPROV provider_; |
| 79 | ScopedHCRYPTKEY key_; |
| 80 | |
| 81 | // Contains the raw key, if it is known during initialization and when it |
| 82 | // is likely that the associated |provider_| will be unable to export the |
| 83 | // |key_|. This is the case of HMAC keys when the key size exceeds 16 bytes |
| 84 | // when using the default RSA provider. |
| 85 | // TODO(rsleevi): See if KP_EFFECTIVE_KEYLEN is the reason why CryptExportKey |
| 86 | // fails with NTE_BAD_KEY/NTE_BAD_LEN |
| 87 | std::string raw_key_; |
| 88 | #elif defined(USE_OPENSSL) |
| 89 | SymmetricKey() {} |
| 90 | std::string key_; |
| 91 | #elif defined(USE_NSS_CERTS) || defined(OS_WIN) || defined(OS_MACOSX) |
| 92 | explicit SymmetricKey(PK11SymKey* key); |
| 93 | ScopedPK11SymKey key_; |
| 94 | #endif |
| 95 | |
| 96 | DISALLOW_COPY_AND_ASSIGN(SymmetricKey); |
| 97 | }; |
| 98 | |
| 99 | } // namespace crypto |
| 100 | |
| 101 | #endif // CRYPTO_SYMMETRIC_KEY_H_ |