BitCoin cheap clone proof-of-concept

deicoin.py

fibCache = [1, 1]
fibMax = 0;

def isFib(n):
    global fibMax
    if n <= 1:
        return True
    else:
        while fibMax < n:
            fibMax = sum(fibCache[-2:])
            fibCache.append(fibMax)
        return n in fibCache

def isSolution(n):
    return isFib(n)

def mining(s=0, n=100):
    return [ i for i in range(s, n) if isSolution(i) ]


# Server

def encode(n, i, passw):
    return ("Token", n, i, passw)

serverSolutions = [1]
serverUpdates = {}

def getMax():
    return serverSolutions[-1]

def isValid(n, passw):
    if n in serverSolutions:
        return None
    else:
        serverSolutions.append(n)
        serverUpdates[n] = 0
        return encode(n, 0, passw)
    
def isUpdated(n, i):
    if n not in serverUpdates: 
        return False
    if serverUpdates[n] > i:
        return False
    else:
        serverUpdates[n] = i
        return True
    
def update(n, i, passw):
    if serverUpdates[n] < i:
        serverUpdates[n] = i
        return encode(n, i, passw)
    return False

# Client

def decode(token, passw):
    if token[3] == passw:
        return token[1:3]
    else:
        return (0,0)
        
def check(token, pass_f):
    n, i = decode(token, pass_f)
    if n == 0 and i == 0:
        return False
    return isUpdated(n, i)
        
def transaction(goods, pass_f, pass_t, annonymous=False):
    print "Transferring %s" % str(goods)
    n, i = decode(goods, pass_f)
    if not isUpdated(n, i):
        print "Owner does not own the goods"
        return False
    ni = i + 1
    if annonymous:
        return encode(n, ni, pass_t)
    else:
        return update(n, ni, pass_t)
    
pass_alcides = "alcides"
tries = mining(getMax(), getMax() + 100)
keychain_alcides = filter(lambda x: x, map(lambda x: isValid(x, pass_alcides), tries))
print "\n".join(map(str,keychain_alcides))
print ".........."


pass_raul = "raul"
tries = mining(getMax(), getMax() + 200)
keychain_raul = filter(lambda x: x, map(lambda x: isValid(x, pass_raul), tries))
print "\n".join(map(str,keychain_raul))
print ".........."


goods = keychain_alcides[1]
new_token = transaction(goods, pass_alcides, pass_raul)
keychain_raul.append(new_token)
print "Raul got ", new_token
if check(goods, pass_alcides) != False or check(new_token, pass_raul) != True:
    print "Transaction failed!"
else:
    print "Transaction successful!"


pass_joaquim = 'joaquim'
keychain_joaquim = []
goods = keychain_raul[-1]
new_token = transaction(goods, pass_raul, pass_joaquim, annonymous=True)
keychain_joaquim.append(new_token)
print "Joaquim got unverified ", new_token
    
    
pass_maria = 'maria'
keychain_maria = []
goods = keychain_raul[-1]
new_token = transaction(goods, pass_raul, pass_maria, annonymous=True)
keychain_maria.append(new_token)
print "Maria got unverified ", new_token
    

goods = keychain_joaquim[-1]
new_token = transaction(goods, pass_joaquim, pass_alcides)
keychain_alcides.append(new_token)
print "Alcides got unverified ", new_token
if check(goods, pass_joaquim) != False or check(new_token, pass_alcides) != True:
    print "Transaction failed!"
else:
    print "Transaction successful!"

if check(keychain_maria[-1], pass_maria) != False:
    print "Maria still has the old key"