93 lines
3.1 KiB
Python
93 lines
3.1 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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Symmetric Encryption
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"""
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# Copyright (C) 2011 Yann GUIBET <yannguibet@gmail.com>
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# See LICENSE for details.
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from openssl import OpenSSL
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# pylint: disable=redefined-builtin
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class Cipher(object):
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"""
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Main class for encryption
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import pyelliptic
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iv = pyelliptic.Cipher.gen_IV('aes-256-cfb')
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ctx = pyelliptic.Cipher("secretkey", iv, 1, ciphername='aes-256-cfb')
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ciphertext = ctx.update('test1')
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ciphertext += ctx.update('test2')
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ciphertext += ctx.final()
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ctx2 = pyelliptic.Cipher("secretkey", iv, 0, ciphername='aes-256-cfb')
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print ctx2.ciphering(ciphertext)
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"""
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def __init__(self, key, iv, do, ciphername='aes-256-cbc'):
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"""
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do == 1 => Encrypt; do == 0 => Decrypt
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"""
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self.cipher = OpenSSL.get_cipher(ciphername)
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self.ctx = OpenSSL.EVP_CIPHER_CTX_new()
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if do == 1 or do == 0:
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k = OpenSSL.malloc(key, len(key))
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IV = OpenSSL.malloc(iv, len(iv))
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OpenSSL.EVP_CipherInit_ex(
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self.ctx, self.cipher.get_pointer(), 0, k, IV, do)
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else:
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raise Exception("RTFM ...")
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@staticmethod
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def get_all_cipher():
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"""
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static method, returns all ciphers available
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"""
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return OpenSSL.cipher_algo.keys()
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@staticmethod
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def get_blocksize(ciphername):
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"""This Method returns cipher blocksize"""
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cipher = OpenSSL.get_cipher(ciphername)
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return cipher.get_blocksize()
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@staticmethod
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def gen_IV(ciphername):
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"""Generate random initialization vector"""
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cipher = OpenSSL.get_cipher(ciphername)
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return OpenSSL.rand(cipher.get_blocksize())
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def update(self, input):
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"""Update result with more data"""
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i = OpenSSL.c_int(0)
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buffer = OpenSSL.malloc(b"", len(input) + self.cipher.get_blocksize())
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inp = OpenSSL.malloc(input, len(input))
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if OpenSSL.EVP_CipherUpdate(self.ctx, OpenSSL.byref(buffer),
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OpenSSL.byref(i), inp, len(input)) == 0:
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raise Exception("[OpenSSL] EVP_CipherUpdate FAIL ...")
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return buffer.raw[0:i.value] # pylint: disable=invalid-slice-index
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def final(self):
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"""Returning the final value"""
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i = OpenSSL.c_int(0)
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buffer = OpenSSL.malloc(b"", self.cipher.get_blocksize())
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if (OpenSSL.EVP_CipherFinal_ex(self.ctx, OpenSSL.byref(buffer),
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OpenSSL.byref(i))) == 0:
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raise Exception("[OpenSSL] EVP_CipherFinal_ex FAIL ...")
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return buffer.raw[0:i.value] # pylint: disable=invalid-slice-index
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def ciphering(self, input):
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"""
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Do update and final in one method
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"""
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buff = self.update(input)
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return buff + self.final()
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def __del__(self):
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# pylint: disable=protected-access
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if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
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OpenSSL.EVP_CIPHER_CTX_reset(self.ctx)
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else:
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OpenSSL.EVP_CIPHER_CTX_cleanup(self.ctx)
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OpenSSL.EVP_CIPHER_CTX_free(self.ctx)
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