1 // Copyright (c) 2009-2012 The Bitcoin Developers
2 // Distributed under the MIT/X11 software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 #include <openssl/aes.h>
6 #include <openssl/evp.h>
16 CMasterKey::CMasterKey()
18 // 25000 rounds is just under 0.1 seconds on a 1.86 GHz Pentium M
19 // ie slightly lower than the lowest hardware we need bother supporting
20 nDeriveIterations = 25000;
21 nDerivationMethod = 0;
22 vchOtherDerivationParameters = vector<unsigned char>(0);
29 bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
31 if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
35 if (nDerivationMethod == 0)
37 i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha512(), &chSalt[0],
38 (const unsigned char *)&strKeyData[0], strKeyData.size(), nRounds, chKey, chIV);
41 if (i != (int)WALLET_CRYPTO_KEY_SIZE)
43 OPENSSL_cleanse(&chKey, sizeof chKey);
44 OPENSSL_cleanse(&chIV, sizeof chIV);
52 bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const vector<unsigned char>& chNewIV)
54 if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_KEY_SIZE)
57 memcpy(&chKey[0], &chNewKey[0], sizeof chKey);
58 memcpy(&chIV[0], &chNewIV[0], sizeof chIV);
64 bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, vector<unsigned char> &vchCiphertext)
69 // max ciphertext len for a n bytes of plaintext is
70 // n + AES_BLOCK_SIZE - 1 bytes
71 int nLen = vchPlaintext.size();
72 int nCLen = nLen + AES_BLOCK_SIZE, nFLen = 0;
73 vchCiphertext = vector<unsigned char> (nCLen);
79 EVP_CIPHER_CTX_init(&ctx);
80 if (fOk) fOk = EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV) != 0;
81 if (fOk) fOk = EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen) != 0;
82 if (fOk) fOk = EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0]) + nCLen, &nFLen) != 0;
83 EVP_CIPHER_CTX_cleanup(&ctx);
85 if (!fOk) return false;
87 vchCiphertext.resize(nCLen + nFLen);
91 bool CCrypter::Decrypt(const vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext)
96 // plaintext will always be equal to or lesser than length of ciphertext
97 int nLen = vchCiphertext.size();
98 int nPLen = nLen, nFLen = 0;
100 vchPlaintext = CKeyingMaterial(nPLen);
106 EVP_CIPHER_CTX_init(&ctx);
107 if (fOk) fOk = EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV) != 0;
108 if (fOk) fOk = EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen) != 0;
109 if (fOk) fOk = EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0]) + nPLen, &nFLen) != 0;
110 EVP_CIPHER_CTX_cleanup(&ctx);
112 if (!fOk) return false;
114 vchPlaintext.resize(nPLen + nFLen);
118 void CCrypter::CleanKey()
120 OPENSSL_cleanse(&chKey, sizeof chKey);
121 OPENSSL_cleanse(&chIV, sizeof chIV);
129 // Try to keep the key data out of swap (and be a bit over-careful to keep the IV that we don't even use out of swap)
130 // Note that this does nothing about suspend-to-disk (which will put all our key data on disk)
131 // Note as well that at no point in this program is any attempt made to prevent stealing of keys by reading the memory of the running process.
132 LockedPageManager::instance.LockRange(&chKey[0], sizeof chKey);
133 LockedPageManager::instance.LockRange(&chIV[0], sizeof chIV);
136 CCrypter::~CCrypter()
140 LockedPageManager::instance.UnlockRange(&chKey[0], sizeof chKey);
141 LockedPageManager::instance.UnlockRange(&chIV[0], sizeof chIV);
144 bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, vector<unsigned char> &vchCiphertext)
146 CCrypter cKeyCrypter;
147 vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
148 memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
149 if(!cKeyCrypter.SetKey(vMasterKey, chIV))
151 return cKeyCrypter.Encrypt((CKeyingMaterial)vchPlaintext, vchCiphertext);
154 bool DecryptSecret(const CKeyingMaterial& vMasterKey, const vector<unsigned char>& vchCiphertext, const uint256& nIV, CSecret& vchPlaintext)
156 CCrypter cKeyCrypter;
157 vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
158 memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
159 if(!cKeyCrypter.SetKey(vMasterKey, chIV))
161 return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));