250 lines
9.1 KiB
Python
250 lines
9.1 KiB
Python
import hashlib
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from struct import *
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from pyelliptic import arithmetic
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#There is another copy of this function in Bitmessagemain.py
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def convertIntToString(n):
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a = __builtins__.hex(n)
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if a[-1:] == 'L':
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a = a[:-1]
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if (len(a) % 2) == 0:
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return a[2:].decode('hex')
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else:
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return ('0'+a[2:]).decode('hex')
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ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
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def encodeBase58(num, alphabet=ALPHABET):
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"""Encode a number in Base X
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`num`: The number to encode
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`alphabet`: The alphabet to use for encoding
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"""
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if (num == 0):
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return alphabet[0]
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arr = []
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base = len(alphabet)
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while num:
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rem = num % base
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#print 'num is:', num
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num = num // base
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arr.append(alphabet[rem])
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arr.reverse()
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return ''.join(arr)
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def decodeBase58(string, alphabet=ALPHABET):
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"""Decode a Base X encoded string into the number
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Arguments:
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- `string`: The encoded string
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- `alphabet`: The alphabet to use for encoding
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"""
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base = len(alphabet)
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strlen = len(string)
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num = 0
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try:
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power = strlen - 1
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for char in string:
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num += alphabet.index(char) * (base ** power)
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power -= 1
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except:
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#character not found (like a space character or a 0)
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return 0
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return num
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def encodeVarint(integer):
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if integer < 0:
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print 'varint cannot be < 0'
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raise SystemExit
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if integer < 253:
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return pack('>B',integer)
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if integer >= 253 and integer < 65536:
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return pack('>B',253) + pack('>H',integer)
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if integer >= 65536 and integer < 4294967296:
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return pack('>B',254) + pack('>I',integer)
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if integer >= 4294967296 and integer < 18446744073709551616:
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return pack('>B',255) + pack('>Q',integer)
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if integer >= 18446744073709551616:
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print 'varint cannot be >= 18446744073709551616'
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raise SystemExit
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def decodeVarint(data):
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if len(data) == 0:
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return (0,0)
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firstByte, = unpack('>B',data[0:1])
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if firstByte < 253:
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return (firstByte,1) #the 1 is the length of the varint
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if firstByte == 253:
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a, = unpack('>H',data[1:3])
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return (a,3)
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if firstByte == 254:
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a, = unpack('>I',data[1:5])
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return (a,5)
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if firstByte == 255:
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a, = unpack('>Q',data[1:9])
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return (a,9)
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def calculateInventoryHash(data):
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sha = hashlib.new('sha512')
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sha2 = hashlib.new('sha512')
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sha.update(data)
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sha2.update(sha.digest())
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return sha2.digest()[0:32]
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def encodeAddress(version,stream,ripe):
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if version >= 2 and version < 4:
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if len(ripe) != 20:
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raise Exception("Programming error in encodeAddress: The length of a given ripe hash was not 20.")
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if ripe[:2] == '\x00\x00':
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ripe = ripe[2:]
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elif ripe[:1] == '\x00':
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ripe = ripe[1:]
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elif version == 4:
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if len(ripe) != 20:
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raise Exception("Programming error in encodeAddress: The length of a given ripe hash was not 20.")
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ripe = ripe.lstrip('\x00')
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a = encodeVarint(version) + encodeVarint(stream) + ripe
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sha = hashlib.new('sha512')
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sha.update(a)
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currentHash = sha.digest()
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#print 'sha after first hashing: ', sha.hexdigest()
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sha = hashlib.new('sha512')
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sha.update(currentHash)
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#print 'sha after second hashing: ', sha.hexdigest()
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checksum = sha.digest()[0:4]
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#print 'len(a) = ', len(a)
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#print 'checksum = ', checksum.encode('hex')
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#print 'len(checksum) = ', len(checksum)
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asInt = int(a.encode('hex') + checksum.encode('hex'),16)
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#asInt = int(checksum.encode('hex') + a.encode('hex'),16)
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# print asInt
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return 'BM-'+ encodeBase58(asInt)
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def decodeAddress(address):
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#returns (status, address version number, stream number, data (almost certainly a ripe hash))
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address = str(address).strip()
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if address[:3] == 'BM-':
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integer = decodeBase58(address[3:])
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else:
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integer = decodeBase58(address)
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if integer == 0:
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status = 'invalidcharacters'
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return status,0,0,""
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#after converting to hex, the string will be prepended with a 0x and appended with a L
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hexdata = hex(integer)[2:-1]
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if len(hexdata) % 2 != 0:
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hexdata = '0' + hexdata
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#print 'hexdata', hexdata
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data = hexdata.decode('hex')
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checksum = data[-4:]
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sha = hashlib.new('sha512')
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sha.update(data[:-4])
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currentHash = sha.digest()
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#print 'sha after first hashing: ', sha.hexdigest()
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sha = hashlib.new('sha512')
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sha.update(currentHash)
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#print 'sha after second hashing: ', sha.hexdigest()
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if checksum != sha.digest()[0:4]:
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status = 'checksumfailed'
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return status,0,0,""
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#else:
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# print 'checksum PASSED'
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addressVersionNumber, bytesUsedByVersionNumber = decodeVarint(data[:9])
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#print 'addressVersionNumber', addressVersionNumber
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#print 'bytesUsedByVersionNumber', bytesUsedByVersionNumber
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if addressVersionNumber > 4:
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print 'cannot decode address version numbers this high'
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status = 'versiontoohigh'
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return status,0,0,""
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elif addressVersionNumber == 0:
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print 'cannot decode address version numbers of zero.'
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status = 'versiontoohigh'
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return status,0,0,""
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streamNumber, bytesUsedByStreamNumber = decodeVarint(data[bytesUsedByVersionNumber:])
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#print streamNumber
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status = 'success'
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if addressVersionNumber == 1:
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return status,addressVersionNumber,streamNumber,data[-24:-4]
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elif addressVersionNumber == 2 or addressVersionNumber == 3:
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if len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]) == 19:
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return status,addressVersionNumber,streamNumber,'\x00'+data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]
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elif len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]) == 20:
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return status,addressVersionNumber,streamNumber,data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]
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elif len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]) == 18:
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return status,addressVersionNumber,streamNumber,'\x00\x00'+data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]
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elif len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]) < 18:
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return 'ripetooshort',0,0,""
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elif len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]) > 20:
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return 'ripetoolong',0,0,""
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else:
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return 'otherproblem',0,0,""
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elif addressVersionNumber == 4:
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if len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]) > 20:
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return 'ripetoolong',0,0,""
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elif len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]) < 4:
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return 'ripetooshort',0,0,""
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else:
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x00string = '\x00' * (20 - len(data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]))
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return status,addressVersionNumber,streamNumber,x00string+data[bytesUsedByVersionNumber+bytesUsedByStreamNumber:-4]
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def addBMIfNotPresent(address):
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address = str(address).strip()
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if address[:3] != 'BM-':
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return 'BM-'+address
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else:
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return address
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if __name__ == "__main__":
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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:'
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privateSigningKey = '93d0b61371a54b53df143b954035d612f8efa8a3ed1cf842c2186bfd8f876665'
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privateEncryptionKey = '4b0b73a54e19b059dc274ab69df095fe699f43b17397bca26fdf40f4d7400a3a'
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print 'privateSigningKey =', privateSigningKey
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print 'privateEncryptionKey =', privateEncryptionKey
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print 'Now let us convert them to public keys by doing an elliptic curve point multiplication.'
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publicSigningKey = arithmetic.privtopub(privateSigningKey)
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publicEncryptionKey = arithmetic.privtopub(privateEncryptionKey)
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print 'publicSigningKey =', publicSigningKey
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print 'publicEncryptionKey =', publicEncryptionKey
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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.'
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publicSigningKeyBinary = arithmetic.changebase(publicSigningKey,16,256,minlen=64)
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publicEncryptionKeyBinary = arithmetic.changebase(publicEncryptionKey,16,256,minlen=64)
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ripe = hashlib.new('ripemd160')
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sha = hashlib.new('sha512')
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sha.update(publicSigningKeyBinary+publicEncryptionKeyBinary)
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ripe.update(sha.digest())
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addressVersionNumber = 2
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streamNumber = 1
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print 'Ripe digest that we will encode in the address:', ripe.digest().encode('hex')
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returnedAddress = encodeAddress(addressVersionNumber,streamNumber,ripe.digest())
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print 'Encoded address:', returnedAddress
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status,addressVersionNumber,streamNumber,data = decodeAddress(returnedAddress)
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print '\nAfter decoding address:'
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print 'Status:', status
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print 'addressVersionNumber', addressVersionNumber
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print 'streamNumber', streamNumber
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print 'length of data(the ripe hash):', len(data)
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print 'ripe data:', data.encode('hex')
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