Bitcoin Core  0.19.99
P2P Digital Currency
crypter.cpp
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1 // Copyright (c) 2009-2019 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 
5 #include <wallet/crypter.h>
6 
7 #include <crypto/aes.h>
8 #include <crypto/sha512.h>
9 #include <util/system.h>
10 
11 #include <vector>
12 
13 int CCrypter::BytesToKeySHA512AES(const std::vector<unsigned char>& chSalt, const SecureString& strKeyData, int count, unsigned char *key,unsigned char *iv) const
14 {
15  // This mimics the behavior of openssl's EVP_BytesToKey with an aes256cbc
16  // cipher and sha512 message digest. Because sha512's output size (64b) is
17  // greater than the aes256 block size (16b) + aes256 key size (32b),
18  // there's no need to process more than once (D_0).
19 
20  if(!count || !key || !iv)
21  return 0;
22 
23  unsigned char buf[CSHA512::OUTPUT_SIZE];
24  CSHA512 di;
25 
26  di.Write((const unsigned char*)strKeyData.data(), strKeyData.size());
27  di.Write(chSalt.data(), chSalt.size());
28  di.Finalize(buf);
29 
30  for(int i = 0; i != count - 1; i++)
31  di.Reset().Write(buf, sizeof(buf)).Finalize(buf);
32 
33  memcpy(key, buf, WALLET_CRYPTO_KEY_SIZE);
35  memory_cleanse(buf, sizeof(buf));
37 }
38 
39 bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
40 {
41  if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
42  return false;
43 
44  int i = 0;
45  if (nDerivationMethod == 0)
46  i = BytesToKeySHA512AES(chSalt, strKeyData, nRounds, vchKey.data(), vchIV.data());
47 
48  if (i != (int)WALLET_CRYPTO_KEY_SIZE)
49  {
50  memory_cleanse(vchKey.data(), vchKey.size());
51  memory_cleanse(vchIV.data(), vchIV.size());
52  return false;
53  }
54 
55  fKeySet = true;
56  return true;
57 }
58 
59 bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
60 {
61  if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_IV_SIZE)
62  return false;
63 
64  memcpy(vchKey.data(), chNewKey.data(), chNewKey.size());
65  memcpy(vchIV.data(), chNewIV.data(), chNewIV.size());
66 
67  fKeySet = true;
68  return true;
69 }
70 
71 bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext) const
72 {
73  if (!fKeySet)
74  return false;
75 
76  // max ciphertext len for a n bytes of plaintext is
77  // n + AES_BLOCKSIZE bytes
78  vchCiphertext.resize(vchPlaintext.size() + AES_BLOCKSIZE);
79 
80  AES256CBCEncrypt enc(vchKey.data(), vchIV.data(), true);
81  size_t nLen = enc.Encrypt(&vchPlaintext[0], vchPlaintext.size(), vchCiphertext.data());
82  if(nLen < vchPlaintext.size())
83  return false;
84  vchCiphertext.resize(nLen);
85 
86  return true;
87 }
88 
89 bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext) const
90 {
91  if (!fKeySet)
92  return false;
93 
94  // plaintext will always be equal to or lesser than length of ciphertext
95  int nLen = vchCiphertext.size();
96 
97  vchPlaintext.resize(nLen);
98 
99  AES256CBCDecrypt dec(vchKey.data(), vchIV.data(), true);
100  nLen = dec.Decrypt(vchCiphertext.data(), vchCiphertext.size(), &vchPlaintext[0]);
101  if(nLen == 0)
102  return false;
103  vchPlaintext.resize(nLen);
104  return true;
105 }
106 
107 bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext)
108 {
109  CCrypter cKeyCrypter;
110  std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
111  memcpy(chIV.data(), &nIV, WALLET_CRYPTO_IV_SIZE);
112  if(!cKeyCrypter.SetKey(vMasterKey, chIV))
113  return false;
114  return cKeyCrypter.Encrypt(*((const CKeyingMaterial*)&vchPlaintext), vchCiphertext);
115 }
116 
117 bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& vchPlaintext)
118 {
119  CCrypter cKeyCrypter;
120  std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
121  memcpy(chIV.data(), &nIV, WALLET_CRYPTO_IV_SIZE);
122  if(!cKeyCrypter.SetKey(vMasterKey, chIV))
123  return false;
124  return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
125 }
126 
127 bool DecryptKey(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCryptedSecret, const CPubKey& vchPubKey, CKey& key)
128 {
129  CKeyingMaterial vchSecret;
130  if(!DecryptSecret(vMasterKey, vchCryptedSecret, vchPubKey.GetHash(), vchSecret))
131  return false;
132 
133  if (vchSecret.size() != 32)
134  return false;
135 
136  key.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());
137  return key.VerifyPubKey(vchPubKey);
138 }
bool SetKeyFromPassphrase(const SecureString &strKeyData, const std::vector< unsigned char > &chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
Definition: crypter.cpp:39
const unsigned int WALLET_CRYPTO_KEY_SIZE
Definition: crypter.h:13
bool Encrypt(const CKeyingMaterial &vchPlaintext, std::vector< unsigned char > &vchCiphertext) const
Definition: crypter.cpp:71
bool DecryptKey(const CKeyingMaterial &vMasterKey, const std::vector< unsigned char > &vchCryptedSecret, const CPubKey &vchPubKey, CKey &key)
Definition: crypter.cpp:127
bool SetKey(const CKeyingMaterial &chNewKey, const std::vector< unsigned char > &chNewIV)
Definition: crypter.cpp:59
Encryption/decryption context with key information.
Definition: crypter.h:75
bool VerifyPubKey(const CPubKey &vchPubKey) const
Verify thoroughly whether a private key and a public key match.
Definition: key.cpp:232
std::basic_string< char, std::char_traits< char >, secure_allocator< char > > SecureString
Definition: secure.h:60
uint256 GetHash() const
Get the 256-bit hash of this public key.
Definition: pubkey.h:161
std::vector< unsigned char, secure_allocator< unsigned char > > CKeyingMaterial
Definition: crypter.h:67
int BytesToKeySHA512AES(const std::vector< unsigned char > &chSalt, const SecureString &strKeyData, int count, unsigned char *key, unsigned char *iv) const
Definition: crypter.cpp:13
int Decrypt(const unsigned char *data, int size, unsigned char *out) const
Definition: aes.cpp:144
bool Decrypt(const std::vector< unsigned char > &vchCiphertext, CKeyingMaterial &vchPlaintext) const
Definition: crypter.cpp:89
const unsigned int WALLET_CRYPTO_IV_SIZE
Definition: crypter.h:15
void Finalize(unsigned char hash[OUTPUT_SIZE])
Definition: sha512.cpp:185
void memory_cleanse(void *ptr, size_t len)
Secure overwrite a buffer (possibly containing secret data) with zero-bytes.
Definition: cleanse.cpp:14
std::vector< unsigned char, secure_allocator< unsigned char > > vchKey
Definition: crypter.h:79
std::vector< unsigned char, secure_allocator< unsigned char > > vchIV
Definition: crypter.h:80
bool fKeySet
Definition: crypter.h:81
CSHA512 & Reset()
Definition: sha512.cpp:202
An encapsulated public key.
Definition: pubkey.h:30
int Encrypt(const unsigned char *data, int size, unsigned char *out) const
Definition: aes.cpp:127
static constexpr size_t OUTPUT_SIZE
Definition: sha512.h:20
void Set(const T pbegin, const T pend, bool fCompressedIn)
Initialize using begin and end iterators to byte data.
Definition: key.h:74
256-bit opaque blob.
Definition: uint256.h:120
const unsigned int WALLET_CRYPTO_SALT_SIZE
Definition: crypter.h:14
void * memcpy(void *a, const void *b, size_t c)
bool DecryptSecret(const CKeyingMaterial &vMasterKey, const std::vector< unsigned char > &vchCiphertext, const uint256 &nIV, CKeyingMaterial &vchPlaintext)
Definition: crypter.cpp:117
CSHA512 & Write(const unsigned char *data, size_t len)
Definition: sha512.cpp:159
static int count
Definition: tests.c:45
bool EncryptSecret(const CKeyingMaterial &vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256 &nIV, std::vector< unsigned char > &vchCiphertext)
Definition: crypter.cpp:107
An encapsulated private key.
Definition: key.h:27
A hasher class for SHA-512.
Definition: sha512.h:12
static const int AES_BLOCKSIZE
Definition: aes.h:14
bool IsCompressed() const
Check whether this is a compressed public key.
Definition: pubkey.h:180