import hashlib from struct import * from pyelliptic import arithmetic #There is another copy of this function in Bitmessagemain.py def convertIntToString(n): a = __builtins__.hex(n) if a[-1:] == 'L': a = a[:-1] if (len(a) % 2) == 0: return a[2:].decode('hex') else: return ('0'+a[2:]).decode('hex') ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz" def encodeBase58(num, alphabet=ALPHABET): """Encode a number in Base X `num`: The number to encode `alphabet`: The alphabet to use for encoding """ if (num == 0): return alphabet[0] arr = [] base = len(alphabet) while num: rem = num % base #print 'num is:', num num = num // base arr.append(alphabet[rem]) arr.reverse() return ''.join(arr) def decodeBase58(string, alphabet=ALPHABET): """Decode a Base X encoded string into the number Arguments: - `string`: The encoded string - `alphabet`: The alphabet to use for encoding """ base = len(alphabet) num = 0 try: for char in string: num *= base num += alphabet.index(char) except: #character not found (like a space character or a 0) return 0 return num def encodeVarint(integer): if integer < 0: print 'varint cannot be < 0' raise SystemExit if integer < 253: return pack('>B',integer) if integer >= 253 and integer < 65536: return pack('>B',253) + pack('>H',integer) if integer >= 65536 and integer < 4294967296: return pack('>B',254) + pack('>I',integer) if integer >= 4294967296 and integer < 18446744073709551616: return pack('>B',255) + pack('>Q',integer) if integer >= 18446744073709551616: print 'varint cannot be >= 18446744073709551616' raise SystemExit class varintDecodeError(Exception): pass def decodeVarint(data): """ Decodes an encoded varint to an integer and returns it. Per protocol v3, the encoded value must be encoded with the minimum amount of data possible or else it is malformed. Returns a tuple: (theEncodedValue, theSizeOfTheVarintInBytes) """ if len(data) == 0: return (0,0) firstByte, = unpack('>B',data[0:1]) if firstByte < 253: # encodes 0 to 252 return (firstByte,1) #the 1 is the length of the varint if firstByte == 253: # encodes 253 to 65535 if len(data) < 3: raise varintDecodeError('The first byte of this varint as an integer is %s but the total length is only %s. It needs to be at least 3.' % (firstByte, len(data))) encodedValue, = unpack('>H',data[1:3]) if encodedValue < 253: raise varintDecodeError('This varint does not encode the value with the lowest possible number of bytes.') return (encodedValue,3) if firstByte == 254: # encodes 65536 to 4294967295 if len(data) < 5: raise varintDecodeError('The first byte of this varint as an integer is %s but the total length is only %s. It needs to be at least 5.' % (firstByte, len(data))) encodedValue, = unpack('>I',data[1:5]) if encodedValue < 65536: raise varintDecodeError('This varint does not encode the value with the lowest possible number of bytes.') return (encodedValue,5) if firstByte == 255: # encodes 4294967296 to 18446744073709551615 if len(data) < 9: raise varintDecodeError('The first byte of this varint as an integer is %s but the total length is only %s. It needs to be at least 9.' % (firstByte, len(data))) encodedValue, = unpack('>Q',data[1:9]) if encodedValue < 4294967296: raise varintDecodeError('This varint does not encode the value with the lowest possible number of bytes.') return (encodedValue,9) def calculateInventoryHash(data): sha = hashlib.new('sha512') sha2 = hashlib.new('sha512') sha.update(data) sha2.update(sha.digest()) return sha2.digest()[0:32] def encodeAddress(version,stream,ripe): if version >= 2 and version < 4: if len(ripe) != 20: raise Exception("Programming error in encodeAddress: The length of a given ripe hash was not 20.") if ripe[:2] == '\x00\x00': ripe = ripe[2:] elif ripe[:1] == '\x00': ripe = ripe[1:] elif version == 4: if len(ripe) != 20: raise Exception("Programming error in encodeAddress: The length of a given ripe hash was not 20.") ripe = ripe.lstrip('\x00') storedBinaryData = encodeVarint(version) + encodeVarint(stream) + ripe # Generate the checksum sha = hashlib.new('sha512') sha.update(storedBinaryData) currentHash = sha.digest() sha = hashlib.new('sha512') sha.update(currentHash) checksum = sha.digest()[0:4] asInt = int(storedBinaryData.encode('hex') + checksum.encode('hex'),16) return 'BM-'+ encodeBase58(asInt) def decodeAddress(address): #returns (status, address version number, stream number, data (almost certainly a ripe hash)) address = str(address).strip() if address[:3] == 'BM-': integer = decodeBase58(address[3:]) else: integer = decodeBase58(address) if integer == 0: status = 'invalidcharacters' return status,0,0,"" #after converting to hex, the string will be prepended with a 0x and appended with a L hexdata = hex(integer)[2:-1] if len(hexdata) % 2 != 0: hexdata = '0' + hexdata #print 'hexdata', hexdata data = hexdata.decode('hex') checksum = data[-4:] sha = hashlib.new('sha512') sha.update(data[:-4]) currentHash = sha.digest() #print 'sha after first hashing: ', sha.hexdigest() sha = hashlib.new('sha512') sha.update(currentHash) #print 'sha after second hashing: ', sha.hexdigest() if checksum != sha.digest()[0:4]: status = 'checksumfailed' return status,0,0,"" #else: # print 'checksum PASSED' try: addressVersionNumber, bytesUsedByVersionNumber = decodeVarint(data[:9]) except varintDecodeError as e: print e status = 'varintmalformed' return status,0,0,"" #print 'addressVersionNumber', addressVersionNumber #print 'bytesUsedByVersionNumber', bytesUsedByVersionNumber if addressVersionNumber > 4: print 'cannot decode address version numbers this high' status = 'versiontoohigh' return status,0,0,"" elif addressVersionNumber == 0: print 'cannot decode address version numbers of zero.' status = 'versiontoohigh' return status,0,0,"" try: streamNumber, bytesUsedByStreamNumber = decodeVarint(data[bytesUsedByVersionNumber:]) except varintDecodeError as e: print e status = 'varintmalformed' return status,0,0,"" #print streamNumber status = 'success' if addressVersionNumber == 1: return status,addressVersionNumber,streamNumber,data[-24:-4] elif addressVersionNumber == 2 or addressVersionNumber == 3: embeddedRipeData = data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4] if len(embeddedRipeData) == 19: return status,addressVersionNumber,streamNumber,'\x00'+embeddedRipeData elif len(embeddedRipeData) == 20: return status,addressVersionNumber,streamNumber,embeddedRipeData elif len(embeddedRipeData) == 18: return status,addressVersionNumber,streamNumber,'\x00\x00'+embeddedRipeData elif len(embeddedRipeData) < 18: return 'ripetooshort',0,0,"" elif len(embeddedRipeData) > 20: return 'ripetoolong',0,0,"" else: return 'otherproblem',0,0,"" elif addressVersionNumber == 4: embeddedRipeData = data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4] if embeddedRipeData[0:1] == '\x00': # In order to enforce address non-malleability, encoded RIPE data must have NULL bytes removed from the front return 'encodingproblem',0,0,"" elif len(embeddedRipeData) > 20: return 'ripetoolong',0,0,"" elif len(embeddedRipeData) < 4: return 'ripetooshort',0,0,"" else: x00string = '\x00' * (20 - len(embeddedRipeData)) return status,addressVersionNumber,streamNumber,x00string+embeddedRipeData def addBMIfNotPresent(address): address = str(address).strip() if address[:3] != 'BM-': return 'BM-'+address else: return address if __name__ == "__main__": print 'Let us make an address from scratch. Suppose we generate two random 32 byte values and call the first one the signing key and the second one the encryption key:' privateSigningKey = '93d0b61371a54b53df143b954035d612f8efa8a3ed1cf842c2186bfd8f876665' privateEncryptionKey = '4b0b73a54e19b059dc274ab69df095fe699f43b17397bca26fdf40f4d7400a3a' print 'privateSigningKey =', privateSigningKey print 'privateEncryptionKey =', privateEncryptionKey print 'Now let us convert them to public keys by doing an elliptic curve point multiplication.' publicSigningKey = arithmetic.privtopub(privateSigningKey) publicEncryptionKey = arithmetic.privtopub(privateEncryptionKey) print 'publicSigningKey =', publicSigningKey print 'publicEncryptionKey =', publicEncryptionKey print 'Notice that they both begin with the \\x04 which specifies the encoding type. This prefix is not send over the wire. You must strip if off before you send your public key across the wire, and you must add it back when you receive a public key.' publicSigningKeyBinary = arithmetic.changebase(publicSigningKey,16,256,minlen=64) publicEncryptionKeyBinary = arithmetic.changebase(publicEncryptionKey,16,256,minlen=64) ripe = hashlib.new('ripemd160') sha = hashlib.new('sha512') sha.update(publicSigningKeyBinary+publicEncryptionKeyBinary) ripe.update(sha.digest()) addressVersionNumber = 2 streamNumber = 1 print 'Ripe digest that we will encode in the address:', ripe.digest().encode('hex') returnedAddress = encodeAddress(addressVersionNumber,streamNumber,ripe.digest()) print 'Encoded address:', returnedAddress status,addressVersionNumber,streamNumber,data = decodeAddress(returnedAddress) print '\nAfter decoding address:' print 'Status:', status print 'addressVersionNumber', addressVersionNumber print 'streamNumber', streamNumber print 'length of data(the ripe hash):', len(data) print 'ripe data:', data.encode('hex')