gistfile1.py

def password_hashes(password):
    alpha = sum([c * (i + 1) % 9 for i,c in enumerate(password)])
    beta = (password[0] + password[-1] + len(password)) % 9
    if beta == 0:
        beta = 20
    return alpha, beta

def reverse(seq):
    return seq[::-1]

def decrypt(plaintext, password):
    password = map(ord, password.strip())
    plaintext = map(ord, reverse(plaintext.strip()).decode('hex'))
    alpha, beta = password_hashes(password)
    gamma, plaintext = plaintext[0], plaintext[1:]
    plaintext = [
        (c - beta - gamma - password[(alpha + gamma + i) % len(password)] + 254) % 254
        for i,c in enumerate(plaintext)]
    return ''.join(map(chr, reverse(plaintext)))

def encrypt(plaintext, password):
    plaintext = reverse(map(ord, plaintext.strip()))
    password = map(ord, password.strip())
    alpha, beta = password_hashes(password)
    k = sum([c * (i + 1) % 9 for i,c in enumerate(plaintext)])
    gamma = (alpha + k) % 143
    for i2 in range(len(plaintext)):
        plaintext[i2] = (plaintext[i2] + beta + gamma + password[(alpha + gamma + i2) % len(password)] + 254) % 254
    return reverse((''.join(map(chr, [gamma] + plaintext))).encode('hex').upper())