ARC4 Encryption (ARCFOUR)

ARC4 (ARCFOUR) encryption. The Chilkat encryption component supports the ARC4 streaming encryption algorithm.

Download Chilkat Python Library

import sys
import chilkat

crypt = chilkat.CkCrypt2()

success = crypt.UnlockComponent("Anything for 30-day trial")
if (success != True):
    print "Crypt component unlock failed"
    sys.exit()

#  Set the encryption algorithm = "arc4"
crypt.put_CryptAlgorithm("arc4")

#  KeyLength may range from 1 byte to 256 bytes.
#  (i.e. 8 bits to 2048 bits)
#  ARC4 key sizes are typically in the range of
#  40 to 128 bits.
#  The KeyLength property is specified in bits:
crypt.put_KeyLength(128)

#  Note: The PaddingScheme and CipherMode properties
#  do not apply w/ ARC4.  ARC4 does not encrypt in blocks --
#  it is a streaming encryption algorithm. The number of output bytes
#  is exactly equal to the number of input bytes.

#  EncodingMode specifies the encoding of the output for
#  encryption, and the input for decryption.
#  It may be "hex", "url", "base64", or "quoted-printable".
crypt.put_EncodingMode("hex")

#  Note: ARC4 does not utilize initialization vectors.  IV's only
#  apply to block encryption algorithms.

#  The secret key must equal the size of the key.
#  For 128-bit encryption, the binary secret key is 16 bytes.
keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
crypt.SetEncodedKey(keyHex,"hex")

#  Encrypt a string...
#  The output length is exactly equal to the input.  In this
#  example, the input string is 44 chars (ANSI bytes) so the
#  output is 44 bytes -- and when hex encoded results in an
#  88-char string (2 chars per byte for the hex encoding).
encStr = crypt.encryptStringENC("The quick brown fox jumps over the lazy dog.")
print encStr

#  Now decrypt:
decStr = crypt.decryptStringENC(encStr)
print decStr