1# Author: Trevor Perrin 2# See the LICENSE file for legal information regarding use of this file. 3 4"""Abstract class for RSA.""" 5 6from .cryptomath import * 7 8 9class RSAKey(object): 10 """This is an abstract base class for RSA keys. 11 12 Particular implementations of RSA keys, such as 13 L{openssl_rsakey.OpenSSL_RSAKey}, 14 L{python_rsakey.Python_RSAKey}, and 15 L{pycrypto_rsakey.PyCrypto_RSAKey}, 16 inherit from this. 17 18 To create or parse an RSA key, don't use one of these classes 19 directly. Instead, use the factory functions in 20 L{tlslite.utils.keyfactory}. 21 """ 22 23 def __init__(self, n=0, e=0): 24 """Create a new RSA key. 25 26 If n and e are passed in, the new key will be initialized. 27 28 @type n: int 29 @param n: RSA modulus. 30 31 @type e: int 32 @param e: RSA public exponent. 33 """ 34 raise NotImplementedError() 35 36 def __len__(self): 37 """Return the length of this key in bits. 38 39 @rtype: int 40 """ 41 return numBits(self.n) 42 43 def hasPrivateKey(self): 44 """Return whether or not this key has a private component. 45 46 @rtype: bool 47 """ 48 raise NotImplementedError() 49 50 def hashAndSign(self, bytes): 51 """Hash and sign the passed-in bytes. 52 53 This requires the key to have a private component. It performs 54 a PKCS1-SHA1 signature on the passed-in data. 55 56 @type bytes: str or L{bytearray} of unsigned bytes 57 @param bytes: The value which will be hashed and signed. 58 59 @rtype: L{bytearray} of unsigned bytes. 60 @return: A PKCS1-SHA1 signature on the passed-in data. 61 """ 62 hashBytes = SHA1(bytearray(bytes)) 63 prefixedHashBytes = self._addPKCS1SHA1Prefix(hashBytes) 64 sigBytes = self.sign(prefixedHashBytes) 65 return sigBytes 66 67 def hashAndVerify(self, sigBytes, bytes): 68 """Hash and verify the passed-in bytes with the signature. 69 70 This verifies a PKCS1-SHA1 signature on the passed-in data. 71 72 @type sigBytes: L{bytearray} of unsigned bytes 73 @param sigBytes: A PKCS1-SHA1 signature. 74 75 @type bytes: str or L{bytearray} of unsigned bytes 76 @param bytes: The value which will be hashed and verified. 77 78 @rtype: bool 79 @return: Whether the signature matches the passed-in data. 80 """ 81 hashBytes = SHA1(bytearray(bytes)) 82 83 # Try it with/without the embedded NULL 84 prefixedHashBytes1 = self._addPKCS1SHA1Prefix(hashBytes, False) 85 prefixedHashBytes2 = self._addPKCS1SHA1Prefix(hashBytes, True) 86 result1 = self.verify(sigBytes, prefixedHashBytes1) 87 result2 = self.verify(sigBytes, prefixedHashBytes2) 88 return (result1 or result2) 89 90 def sign(self, bytes): 91 """Sign the passed-in bytes. 92 93 This requires the key to have a private component. It performs 94 a PKCS1 signature on the passed-in data. 95 96 @type bytes: L{bytearray} of unsigned bytes 97 @param bytes: The value which will be signed. 98 99 @rtype: L{bytearray} of unsigned bytes. 100 @return: A PKCS1 signature on the passed-in data. 101 """ 102 if not self.hasPrivateKey(): 103 raise AssertionError() 104 paddedBytes = self._addPKCS1Padding(bytes, 1) 105 m = bytesToNumber(paddedBytes) 106 if m >= self.n: 107 raise ValueError() 108 c = self._rawPrivateKeyOp(m) 109 sigBytes = numberToByteArray(c, numBytes(self.n)) 110 return sigBytes 111 112 def verify(self, sigBytes, bytes): 113 """Verify the passed-in bytes with the signature. 114 115 This verifies a PKCS1 signature on the passed-in data. 116 117 @type sigBytes: L{bytearray} of unsigned bytes 118 @param sigBytes: A PKCS1 signature. 119 120 @type bytes: L{bytearray} of unsigned bytes 121 @param bytes: The value which will be verified. 122 123 @rtype: bool 124 @return: Whether the signature matches the passed-in data. 125 """ 126 if len(sigBytes) != numBytes(self.n): 127 return False 128 paddedBytes = self._addPKCS1Padding(bytes, 1) 129 c = bytesToNumber(sigBytes) 130 if c >= self.n: 131 return False 132 m = self._rawPublicKeyOp(c) 133 checkBytes = numberToByteArray(m, numBytes(self.n)) 134 return checkBytes == paddedBytes 135 136 def encrypt(self, bytes): 137 """Encrypt the passed-in bytes. 138 139 This performs PKCS1 encryption of the passed-in data. 140 141 @type bytes: L{bytearray} of unsigned bytes 142 @param bytes: The value which will be encrypted. 143 144 @rtype: L{bytearray} of unsigned bytes. 145 @return: A PKCS1 encryption of the passed-in data. 146 """ 147 paddedBytes = self._addPKCS1Padding(bytes, 2) 148 m = bytesToNumber(paddedBytes) 149 if m >= self.n: 150 raise ValueError() 151 c = self._rawPublicKeyOp(m) 152 encBytes = numberToByteArray(c, numBytes(self.n)) 153 return encBytes 154 155 def decrypt(self, encBytes): 156 """Decrypt the passed-in bytes. 157 158 This requires the key to have a private component. It performs 159 PKCS1 decryption of the passed-in data. 160 161 @type encBytes: L{bytearray} of unsigned bytes 162 @param encBytes: The value which will be decrypted. 163 164 @rtype: L{bytearray} of unsigned bytes or None. 165 @return: A PKCS1 decryption of the passed-in data or None if 166 the data is not properly formatted. 167 """ 168 if not self.hasPrivateKey(): 169 raise AssertionError() 170 if len(encBytes) != numBytes(self.n): 171 return None 172 c = bytesToNumber(encBytes) 173 if c >= self.n: 174 return None 175 m = self._rawPrivateKeyOp(c) 176 decBytes = numberToByteArray(m, numBytes(self.n)) 177 #Check first two bytes 178 if decBytes[0] != 0 or decBytes[1] != 2: 179 return None 180 #Scan through for zero separator 181 for x in range(1, len(decBytes)-1): 182 if decBytes[x]== 0: 183 break 184 else: 185 return None 186 return decBytes[x+1:] #Return everything after the separator 187 188 def _rawPrivateKeyOp(self, m): 189 raise NotImplementedError() 190 191 def _rawPublicKeyOp(self, c): 192 raise NotImplementedError() 193 194 def acceptsPassword(self): 195 """Return True if the write() method accepts a password for use 196 in encrypting the private key. 197 198 @rtype: bool 199 """ 200 raise NotImplementedError() 201 202 def write(self, password=None): 203 """Return a string containing the key. 204 205 @rtype: str 206 @return: A string describing the key, in whichever format (PEM) 207 is native to the implementation. 208 """ 209 raise NotImplementedError() 210 211 def generate(bits): 212 """Generate a new key with the specified bit length. 213 214 @rtype: L{tlslite.utils.RSAKey.RSAKey} 215 """ 216 raise NotImplementedError() 217 generate = staticmethod(generate) 218 219 220 # ************************************************************************** 221 # Helper Functions for RSA Keys 222 # ************************************************************************** 223 224 def _addPKCS1SHA1Prefix(self, bytes, withNULL=True): 225 # There is a long history of confusion over whether the SHA1 226 # algorithmIdentifier should be encoded with a NULL parameter or 227 # with the parameter omitted. While the original intention was 228 # apparently to omit it, many toolkits went the other way. TLS 1.2 229 # specifies the NULL should be included, and this behavior is also 230 # mandated in recent versions of PKCS #1, and is what tlslite has 231 # always implemented. Anyways, verification code should probably 232 # accept both. However, nothing uses this code yet, so this is 233 # all fairly moot. 234 if not withNULL: 235 prefixBytes = bytearray(\ 236 [0x30,0x1f,0x30,0x07,0x06,0x05,0x2b,0x0e,0x03,0x02,0x1a,0x04,0x14]) 237 else: 238 prefixBytes = bytearray(\ 239 [0x30,0x21,0x30,0x09,0x06,0x05,0x2b,0x0e,0x03,0x02,0x1a,0x05,0x00,0x04,0x14]) 240 prefixedBytes = prefixBytes + bytes 241 return prefixedBytes 242 243 def _addPKCS1Padding(self, bytes, blockType): 244 padLength = (numBytes(self.n) - (len(bytes)+3)) 245 if blockType == 1: #Signature padding 246 pad = [0xFF] * padLength 247 elif blockType == 2: #Encryption padding 248 pad = bytearray(0) 249 while len(pad) < padLength: 250 padBytes = getRandomBytes(padLength * 2) 251 pad = [b for b in padBytes if b != 0] 252 pad = pad[:padLength] 253 else: 254 raise AssertionError() 255 256 padding = bytearray([0,blockType] + pad + [0]) 257 paddedBytes = padding + bytes 258 return paddedBytes 259