(Tcl) ARC4 Encryption (ARCFOUR)

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

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load ./chilkat.dll

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

set crypt [new_CkCrypt2]

# Set the encryption algorithm = "arc4"	
CkCrypt2_put_CryptAlgorithm $crypt "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:
CkCrypt2_put_KeyLength $crypt 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".
CkCrypt2_put_EncodingMode $crypt "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.
set keyHex "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
CkCrypt2_SetEncodedKey $crypt $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).
set encStr [CkCrypt2_encryptStringENC $crypt "The quick brown fox jumps over the lazy dog."]
puts "$encStr"

# Now decrypt:
set decStr [CkCrypt2_decryptStringENC $crypt $encStr]
puts "$decStr"

delete_CkCrypt2 $crypt