1 // Copyright (c) 2011 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 #include "crypto/symmetric_key.h" 6 7 #include <openssl/evp.h> 8 #include <openssl/rand.h> 9 10 #include <algorithm> 11 12 #include "base/logging.h" 13 #include "base/memory/scoped_ptr.h" 14 #include "base/strings/string_util.h" 15 #include "crypto/openssl_util.h" 16 17 namespace crypto { 18 19 SymmetricKey::~SymmetricKey() { 20 std::fill(key_.begin(), key_.end(), '\0'); // Zero out the confidential key. 21 } 22 23 // static 24 SymmetricKey* SymmetricKey::GenerateRandomKey(Algorithm algorithm, 25 size_t key_size_in_bits) { 26 DCHECK_EQ(AES, algorithm); 27 size_t key_size_in_bytes = key_size_in_bits / 8; 28 DCHECK_EQ(key_size_in_bits, key_size_in_bytes * 8); 29 30 if (key_size_in_bytes == 0) 31 return NULL; 32 33 OpenSSLErrStackTracer err_tracer(FROM_HERE); 34 scoped_ptr<SymmetricKey> key(new SymmetricKey); 35 uint8* key_data = 36 reinterpret_cast<uint8*>(WriteInto(&key->key_, key_size_in_bytes + 1)); 37 38 int rv = RAND_bytes(key_data, static_cast<int>(key_size_in_bytes)); 39 return rv == 1 ? key.release() : NULL; 40 } 41 42 // static 43 SymmetricKey* SymmetricKey::DeriveKeyFromPassword(Algorithm algorithm, 44 const std::string& password, 45 const std::string& salt, 46 size_t iterations, 47 size_t key_size_in_bits) { 48 DCHECK(algorithm == AES || algorithm == HMAC_SHA1); 49 size_t key_size_in_bytes = key_size_in_bits / 8; 50 DCHECK_EQ(key_size_in_bits, key_size_in_bytes * 8); 51 52 if (key_size_in_bytes == 0) 53 return NULL; 54 55 OpenSSLErrStackTracer err_tracer(FROM_HERE); 56 scoped_ptr<SymmetricKey> key(new SymmetricKey); 57 uint8* key_data = 58 reinterpret_cast<uint8*>(WriteInto(&key->key_, key_size_in_bytes + 1)); 59 int rv = PKCS5_PBKDF2_HMAC_SHA1(password.data(), password.length(), 60 reinterpret_cast<const uint8*>(salt.data()), 61 salt.length(), iterations, 62 static_cast<int>(key_size_in_bytes), 63 key_data); 64 return rv == 1 ? key.release() : NULL; 65 } 66 67 // static 68 SymmetricKey* SymmetricKey::Import(Algorithm algorithm, 69 const std::string& raw_key) { 70 scoped_ptr<SymmetricKey> key(new SymmetricKey); 71 key->key_ = raw_key; 72 return key.release(); 73 } 74 75 bool SymmetricKey::GetRawKey(std::string* raw_key) { 76 *raw_key = key_; 77 return true; 78 } 79 80 } // namespace crypto 81
