Generate/validate a QR code value.

qr.py

"""
Easy version...
 
def qr_hash(prefix, data_to_hash):
        qr = ""
        for char in prefix:
                qr += hex(ord(char))[2:]
        qr += md5(data_to_hash).hexdigest()
        return qr
 
def verify_qr(prefix, qr):
        prefix_hex = ""
        for char in prefix:
                prefix_hex += hex(ord(char))[2:]
        return qr.startswith(prefix_hex)
"""
 
from hashlib import md5
 
asciihex = lambda string: "".join([hex(ord(x))[2:] for x in string])
 
def qr_hash(prefix, data_to_hash):
        return asciihex(prefix) + md5(data_to_hash).hexdigest()
 
def verify_qr(prefix, qr):
        return qr.startswith(asciihex(prefix))
 
"""
In [1]: qr = qr_hash("ABC", "Hello World!")
 
In [2]: qr
Out[2]: '414243ed076287532e86365e841e92bfc50d8c'
 
In [3]: verify_qr("ABC", qr)
Out[3]: True
 
In [4]: verify_qr("XYZ", qr)
Out[4]: False
"""