Bitcoin Core  24.99.0
P2P Digital Currency
crypter.cpp
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1 // Copyright (c) 2009-2021 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 namespace wallet {
14 int CCrypter::BytesToKeySHA512AES(const std::vector<unsigned char>& chSalt, const SecureString& strKeyData, int count, unsigned char *key,unsigned char *iv) const
15 {
16  // This mimics the behavior of openssl's EVP_BytesToKey with an aes256cbc
17  // cipher and sha512 message digest. Because sha512's output size (64b) is
18  // greater than the aes256 block size (16b) + aes256 key size (32b),
19  // there's no need to process more than once (D_0).
20 
21  if(!count || !key || !iv)
22  return 0;
23 
24  unsigned char buf[CSHA512::OUTPUT_SIZE];
25  CSHA512 di;
26 
27  di.Write((const unsigned char*)strKeyData.data(), strKeyData.size());
28  di.Write(chSalt.data(), chSalt.size());
29  di.Finalize(buf);
30 
31  for(int i = 0; i != count - 1; i++)
32  di.Reset().Write(buf, sizeof(buf)).Finalize(buf);
33 
34  memcpy(key, buf, WALLET_CRYPTO_KEY_SIZE);
36  memory_cleanse(buf, sizeof(buf));
38 }
39 
40 bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
41 {
42  if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
43  return false;
44 
45  int i = 0;
46  if (nDerivationMethod == 0)
47  i = BytesToKeySHA512AES(chSalt, strKeyData, nRounds, vchKey.data(), vchIV.data());
48 
49  if (i != (int)WALLET_CRYPTO_KEY_SIZE)
50  {
51  memory_cleanse(vchKey.data(), vchKey.size());
52  memory_cleanse(vchIV.data(), vchIV.size());
53  return false;
54  }
55 
56  fKeySet = true;
57  return true;
58 }
59 
60 bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
61 {
62  if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_IV_SIZE)
63  return false;
64 
65  memcpy(vchKey.data(), chNewKey.data(), chNewKey.size());
66  memcpy(vchIV.data(), chNewIV.data(), chNewIV.size());
67 
68  fKeySet = true;
69  return true;
70 }
71 
72 bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext) const
73 {
74  if (!fKeySet)
75  return false;
76 
77  // max ciphertext len for a n bytes of plaintext is
78  // n + AES_BLOCKSIZE bytes
79  vchCiphertext.resize(vchPlaintext.size() + AES_BLOCKSIZE);
80 
81  AES256CBCEncrypt enc(vchKey.data(), vchIV.data(), true);
82  size_t nLen = enc.Encrypt(vchPlaintext.data(), vchPlaintext.size(), vchCiphertext.data());
83  if(nLen < vchPlaintext.size())
84  return false;
85  vchCiphertext.resize(nLen);
86 
87  return true;
88 }
89 
90 bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext) const
91 {
92  if (!fKeySet)
93  return false;
94 
95  // plaintext will always be equal to or lesser than length of ciphertext
96  int nLen = vchCiphertext.size();
97 
98  vchPlaintext.resize(nLen);
99 
100  AES256CBCDecrypt dec(vchKey.data(), vchIV.data(), true);
101  nLen = dec.Decrypt(vchCiphertext.data(), vchCiphertext.size(), vchPlaintext.data());
102  if(nLen == 0)
103  return false;
104  vchPlaintext.resize(nLen);
105  return true;
106 }
107 
108 bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext)
109 {
110  CCrypter cKeyCrypter;
111  std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
112  memcpy(chIV.data(), &nIV, WALLET_CRYPTO_IV_SIZE);
113  if(!cKeyCrypter.SetKey(vMasterKey, chIV))
114  return false;
115  return cKeyCrypter.Encrypt(*((const CKeyingMaterial*)&vchPlaintext), vchCiphertext);
116 }
117 
118 bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& vchPlaintext)
119 {
120  CCrypter cKeyCrypter;
121  std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
122  memcpy(chIV.data(), &nIV, WALLET_CRYPTO_IV_SIZE);
123  if(!cKeyCrypter.SetKey(vMasterKey, chIV))
124  return false;
125  return cKeyCrypter.Decrypt(vchCiphertext, vchPlaintext);
126 }
127 
128 bool DecryptKey(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCryptedSecret, const CPubKey& vchPubKey, CKey& key)
129 {
130  CKeyingMaterial vchSecret;
131  if(!DecryptSecret(vMasterKey, vchCryptedSecret, vchPubKey.GetHash(), vchSecret))
132  return false;
133 
134  if (vchSecret.size() != 32)
135  return false;
136 
137  key.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());
138  return key.VerifyPubKey(vchPubKey);
139 }
140 } // namespace wallet
static const int AES_BLOCKSIZE
Definition: aes.h:14
int Decrypt(const unsigned char *data, int size, unsigned char *out) const
Definition: aes.cpp:144
int Encrypt(const unsigned char *data, int size, unsigned char *out) const
Definition: aes.cpp:127
An encapsulated private key.
Definition: key.h:27
void Set(const T pbegin, const T pend, bool fCompressedIn)
Initialize using begin and end iterators to byte data.
Definition: key.h:73
bool VerifyPubKey(const CPubKey &vchPubKey) const
Verify thoroughly whether a private key and a public key match.
Definition: key.cpp:241
An encapsulated public key.
Definition: pubkey.h:34
bool IsCompressed() const
Check whether this is a compressed public key.
Definition: pubkey.h:198
uint256 GetHash() const
Get the 256-bit hash of this public key.
Definition: pubkey.h:170
A hasher class for SHA-512.
Definition: sha512.h:13
static constexpr size_t OUTPUT_SIZE
Definition: sha512.h:20
CSHA512 & Reset()
Definition: sha512.cpp:202
void Finalize(unsigned char hash[OUTPUT_SIZE])
Definition: sha512.cpp:185
CSHA512 & Write(const unsigned char *data, size_t len)
Definition: sha512.cpp:159
256-bit opaque blob.
Definition: uint256.h:119
Encryption/decryption context with key information.
Definition: crypter.h:71
bool Decrypt(const std::vector< unsigned char > &vchCiphertext, CKeyingMaterial &vchPlaintext) const
Definition: crypter.cpp:90
std::vector< unsigned char, secure_allocator< unsigned char > > vchKey
Definition: crypter.h:74
bool Encrypt(const CKeyingMaterial &vchPlaintext, std::vector< unsigned char > &vchCiphertext) const
Definition: crypter.cpp:72
std::vector< unsigned char, secure_allocator< unsigned char > > vchIV
Definition: crypter.h:75
bool SetKeyFromPassphrase(const SecureString &strKeyData, const std::vector< unsigned char > &chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
Definition: crypter.cpp:40
bool SetKey(const CKeyingMaterial &chNewKey, const std::vector< unsigned char > &chNewIV)
Definition: crypter.cpp:60
int BytesToKeySHA512AES(const std::vector< unsigned char > &chSalt, const SecureString &strKeyData, int count, unsigned char *key, unsigned char *iv) const
Definition: crypter.cpp:14
void memory_cleanse(void *ptr, size_t len)
Secure overwrite a buffer (possibly containing secret data) with zero-bytes.
Definition: cleanse.cpp:14
Definition: node.h:39
std::vector< unsigned char, secure_allocator< unsigned char > > CKeyingMaterial
Definition: crypter.h:62
bool DecryptSecret(const CKeyingMaterial &vMasterKey, const std::vector< unsigned char > &vchCiphertext, const uint256 &nIV, CKeyingMaterial &vchPlaintext)
Definition: crypter.cpp:118
bool DecryptKey(const CKeyingMaterial &vMasterKey, const std::vector< unsigned char > &vchCryptedSecret, const CPubKey &vchPubKey, CKey &key)
Definition: crypter.cpp:128
const unsigned int WALLET_CRYPTO_KEY_SIZE
Definition: crypter.h:14
const unsigned int WALLET_CRYPTO_IV_SIZE
Definition: crypter.h:16
const unsigned int WALLET_CRYPTO_SALT_SIZE
Definition: crypter.h:15
bool EncryptSecret(const CKeyingMaterial &vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256 &nIV, std::vector< unsigned char > &vchCiphertext)
Definition: crypter.cpp:108
std::basic_string< char, std::char_traits< char >, secure_allocator< char > > SecureString
Definition: secure.h:59
static int count
Definition: tests.c:33