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/evp.h>
15 CMasterKey::CMasterKey()
17 // 25000 rounds is just under 0.1 seconds on a 1.86 GHz Pentium M
18 // ie slightly lower than the lowest hardware we need bother supporting
19 nDeriveIterations = 25000;
20 nDerivationMethod = 0;
21 vchOtherDerivationParameters = vector<unsigned char>(0);
28 bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
30 if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
34 if (nDerivationMethod == 0)
36 i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha512(), &chSalt[0],
37 (const unsigned char *)&strKeyData[0], strKeyData.size(), nRounds, chKey, chIV);
40 if (i != (int)WALLET_CRYPTO_KEY_SIZE)
42 OPENSSL_cleanse(&chKey, sizeof chKey);
43 OPENSSL_cleanse(&chIV, sizeof chIV);
51 bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const vector<unsigned char>& chNewIV)
53 if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_KEY_SIZE)
56 memcpy(&chKey[0], &chNewKey[0], sizeof chKey);
57 memcpy(&chIV[0], &chNewIV[0], sizeof chIV);
63 bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, vector<unsigned char> &vchCiphertext)
68 const int AES_BLOCK_SIZE = 16; // taken from <openssl/aes.h>
70 // max ciphertext len for a n bytes of plaintext is
71 // n + AES_BLOCK_SIZE - 1 bytes
72 int nLen = vchPlaintext.size();
73 int nCLen = nLen + AES_BLOCK_SIZE, nFLen = 0;
74 vchCiphertext = vector<unsigned char> (nCLen);
80 EVP_CIPHER_CTX_init(&ctx);
81 if (fOk) fOk = EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV) != 0;
82 if (fOk) fOk = EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen) != 0;
83 if (fOk) fOk = EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0]) + nCLen, &nFLen) != 0;
84 EVP_CIPHER_CTX_cleanup(&ctx);
86 if (!fOk) return false;
88 vchCiphertext.resize(nCLen + nFLen);
92 bool CCrypter::Decrypt(const vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext)
97 // plaintext will always be equal to or lesser than length of ciphertext
98 int nLen = vchCiphertext.size();
99 int nPLen = nLen, nFLen = 0;
101 vchPlaintext = CKeyingMaterial(nPLen);
107 EVP_CIPHER_CTX_init(&ctx);
108 if (fOk) fOk = EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV) != 0;
109 if (fOk) fOk = EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen) != 0;
110 if (fOk) fOk = EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0]) + nPLen, &nFLen) != 0;
111 EVP_CIPHER_CTX_cleanup(&ctx);
113 if (!fOk) return false;
115 vchPlaintext.resize(nPLen + nFLen);
119 void CCrypter::CleanKey()
121 OPENSSL_cleanse(&chKey, sizeof chKey);
122 OPENSSL_cleanse(&chIV, sizeof chIV);
130 // 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)
131 // Note that this does nothing about suspend-to-disk (which will put all our key data on disk)
132 // 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.
133 LockedPageManager::instance.LockRange(&chKey[0], sizeof chKey);
134 LockedPageManager::instance.LockRange(&chIV[0], sizeof chIV);
137 CCrypter::~CCrypter()
141 LockedPageManager::instance.UnlockRange(&chKey[0], sizeof chKey);
142 LockedPageManager::instance.UnlockRange(&chIV[0], sizeof chIV);
145 bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, vector<unsigned char> &vchCiphertext)
147 CCrypter cKeyCrypter;
148 vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
149 memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
150 if(!cKeyCrypter.SetKey(vMasterKey, chIV))
152 return cKeyCrypter.Encrypt((CKeyingMaterial)vchPlaintext, vchCiphertext);
155 bool DecryptSecret(const CKeyingMaterial& vMasterKey, const vector<unsigned char>& vchCiphertext, const uint256& nIV, CSecret& vchPlaintext)
157 CCrypter cKeyCrypter;
158 vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
159 memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
160 if(!cKeyCrypter.SetKey(vMasterKey, chIV))
162 return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));