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DES symmetric cipher
DES (Data Encryption Standard) is a symmetric block cipher standardized by NIST . It has a fixed data block size of 8 bytes. Its keys are 64 bits long, even though 8 bits were used for integrity (now they are ignored) and do not contribute to securty.
DES is cryptographically secure, but its key length is too short by nowadays standards and it could be brute forced with some effort.
DES should not be used for new designs. Use AES.
As an example, encryption can be done as follows:
>>> from Crypto.Cipher import DES3 >>> from Crypto import Random >>> >>> key = b'Sixteen byte key' >>> iv = Random.new().read(DES3.block_size) >>> cipher = DES3.new(key, DES3.MODE_OFB, iv) >>> plaintext = b'sona si latine loqueris ' >>> msg = iv + cipher.encrypt(plaintext)
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DESCipher DES cipher object |
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MODE_ECB = 1 Electronic Code Book (ECB). See blockalgo.MODE_ECB. |
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MODE_CBC = 2 Cipher-Block Chaining (CBC). See blockalgo.MODE_CBC. |
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MODE_CFB = 3 Cipher FeedBack (CFB). See blockalgo.MODE_CFB. |
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MODE_PGP = 4 This mode should not be used. |
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MODE_OFB = 5 Output FeedBack (OFB). See blockalgo.MODE_OFB. |
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MODE_CTR = 6 CounTer Mode (CTR). See blockalgo.MODE_CTR. |
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MODE_OPENPGP = 7 OpenPGP Mode. See blockalgo.MODE_OPENPGP. |
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block_size = 8 Size of a data block (in bytes) |
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key_size = 8 Size of a key (in bytes) |
Function Details |
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