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42 lines
1.3 KiB
42 lines
1.3 KiB
6 years ago
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"""
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Encryption module that uses the Java Cryptography Extensions (JCE).
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Note that in default installations of the Java Runtime Environment, the
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maximum key length is limited to 128 bits due to US export
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restrictions. This makes the generated keys incompatible with the ones
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generated by pycryptopp, which has no such restrictions. To fix this,
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download the "Unlimited Strength Jurisdiction Policy Files" from Sun,
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which will allow encryption using 256 bit AES keys.
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"""
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from warnings import warn
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from javax.crypto import Cipher
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from javax.crypto.spec import SecretKeySpec, IvParameterSpec
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import jarray
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# Initialization vector filled with zeros
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_iv = IvParameterSpec(jarray.zeros(16, 'b'))
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def aesEncrypt(data, key):
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cipher = Cipher.getInstance('AES/CTR/NoPadding')
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skeySpec = SecretKeySpec(key, 'AES')
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cipher.init(Cipher.ENCRYPT_MODE, skeySpec, _iv)
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return cipher.doFinal(data).tostring()
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# magic.
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aesDecrypt = aesEncrypt
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has_aes = True
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def getKeyLength():
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maxlen = Cipher.getMaxAllowedKeyLength('AES/CTR/NoPadding')
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return min(maxlen, 256) / 8
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if getKeyLength() < 32:
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warn('Crypto implementation only supports key lengths up to %d bits. '
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'Generated session cookies may be incompatible with other '
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'environments' % (getKeyLength() * 8))
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