54 lines
1.7 KiB
Python
54 lines
1.7 KiB
Python
"""
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XTEA Block Encryption Algorithm
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Author: Paul Chakravarti (paul_dot_chakravarti_at_gmail_dot_com)
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License: Public Domain
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"""
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def get_key():
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# Encryption key is datetime of creation of DocType, DocType"
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import webnotes
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return webnotes.conn.sql("select creation from tabDocType where name='DocType'")[0][0].strftime('%Y%m%d%H%M%s')[:16]
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def encrypt(data, encryption_key = None):
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if not encryption_key:
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encryption_key = get_key()
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return crypt(encryption_key, data).encode('hex')
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def decrypt(data, encryption_key = None):
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if not encryption_key:
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encryption_key = get_key()
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return crypt(encryption_key, data.decode('hex'))
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def crypt(key,data,iv='\00\00\00\00\00\00\00\00',n=32):
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def keygen(key,iv,n):
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while True:
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iv = xtea_encrypt(key,iv,n)
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for k in iv:
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yield ord(k)
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xor = [ chr(x^y) for (x,y) in zip(map(ord,data),keygen(key,iv,n)) ]
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return "".join(xor)
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def xtea_encrypt(key,block,n=32,endian="!"):
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import struct
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v0,v1 = struct.unpack(endian+"2L",block)
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k = struct.unpack(endian+"4L",key)
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sum,delta,mask = 0L,0x9e3779b9L,0xffffffffL
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for round in range(n):
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v0 = (v0 + (((v1<<4 ^ v1>>5) + v1) ^ (sum + k[sum & 3]))) & mask
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sum = (sum + delta) & mask
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v1 = (v1 + (((v0<<4 ^ v0>>5) + v0) ^ (sum + k[sum>>11 & 3]))) & mask
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return struct.pack(endian+"2L",v0,v1)
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def xtea_decrypt(key,block,n=32,endian="!"):
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import struct
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v0,v1 = struct.unpack(endian+"2L",block)
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k = struct.unpack(endian+"4L",key)
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delta,mask = 0x9e3779b9L,0xffffffffL
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sum = (delta * n) & mask
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for round in range(n):
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v1 = (v1 - (((v0<<4 ^ v0>>5) + v0) ^ (sum + k[sum>>11 & 3]))) & mask
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sum = (sum - delta) & mask
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v0 = (v0 - (((v1<<4 ^ v1>>5) + v1) ^ (sum + k[sum & 3]))) & mask
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return struct.pack(endian+"2L",v0,v1)
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