Projects : bitcoin : bitcoin_tx_fee_cleanup

bitcoin/src/crypter.cpp

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1// Copyright (c) 2011 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.
4
5#include <openssl/aes.h>
6#include <openssl/evp.h>
7#include <vector>
8#include <string>
9#include "headers.h"
10
11#include "crypter.h"
12#include "main.h"
13#include "util.h"
14
15bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
16{
17 if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
18 return false;
19
20 // Try to keep the keydata out of swap (and be a bit over-careful to keep the IV that we don't even use out of swap)
21 // Note that this does nothing about suspend-to-disk (which will put all our key data on disk)
22 // 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.
23 mlock(&chKey[0], sizeof chKey);
24 mlock(&chIV[0], sizeof chIV);
25
26 int i = 0;
27 if (nDerivationMethod == 0)
28 i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha512(), &chSalt[0],
29 (unsigned char *)&strKeyData[0], strKeyData.size(), nRounds, chKey, chIV);
30
31 if (i != WALLET_CRYPTO_KEY_SIZE)
32 {
33 memset(&chKey, 0, sizeof chKey);
34 memset(&chIV, 0, sizeof chIV);
35 return false;
36 }
37
38 fKeySet = true;
39 return true;
40}
41
42bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
43{
44 if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_KEY_SIZE)
45 return false;
46
47 // Try to keep the keydata out of swap
48 // Note that this does nothing about suspend-to-disk (which will put all our key data on disk)
49 // 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.
50 mlock(&chKey[0], sizeof chKey);
51 mlock(&chIV[0], sizeof chIV);
52
53 memcpy(&chKey[0], &chNewKey[0], sizeof chKey);
54 memcpy(&chIV[0], &chNewIV[0], sizeof chIV);
55
56 fKeySet = true;
57 return true;
58}
59
60bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext)
61{
62 if (!fKeySet)
63 return false;
64
65 // max ciphertext len for a n bytes of plaintext is
66 // n + AES_BLOCK_SIZE - 1 bytes
67 int nLen = vchPlaintext.size();
68 int nCLen = nLen + AES_BLOCK_SIZE, nFLen = 0;
69 vchCiphertext = std::vector<unsigned char> (nCLen);
70
71 EVP_CIPHER_CTX ctx;
72
73 EVP_CIPHER_CTX_init(&ctx);
74 EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
75
76 EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen);
77 EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0])+nCLen, &nFLen);
78
79 EVP_CIPHER_CTX_cleanup(&ctx);
80
81 vchCiphertext.resize(nCLen + nFLen);
82 return true;
83}
84
85bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext)
86{
87 if (!fKeySet)
88 return false;
89
90 // plaintext will always be equal to or lesser than length of ciphertext
91 int nLen = vchCiphertext.size();
92 int nPLen = nLen, nFLen = 0;
93
94 vchPlaintext = CKeyingMaterial(nPLen);
95
96 EVP_CIPHER_CTX ctx;
97
98 EVP_CIPHER_CTX_init(&ctx);
99 EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
100
101 EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen);
102 EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0])+nPLen, &nFLen);
103
104 EVP_CIPHER_CTX_cleanup(&ctx);
105
106 vchPlaintext.resize(nPLen + nFLen);
107 return true;
108}
109
110
111bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext)
112{
113 CCrypter cKeyCrypter;
114 std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
115 memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
116 if(!cKeyCrypter.SetKey(vMasterKey, chIV))
117 return false;
118 return cKeyCrypter.Encrypt((CKeyingMaterial)vchPlaintext, vchCiphertext);
119}
120
121bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CSecret& vchPlaintext)
122{
123 CCrypter cKeyCrypter;
124 std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
125 memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
126 if(!cKeyCrypter.SetKey(vMasterKey, chIV))
127 return false;
128 return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
129}