(Tcl) AES OFB Output Feedback Mode Encryption

Demonstrates how to encrypt using AES OFB (Output Feedback) mode.

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load ./chilkat.dll

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

set crypt [new_CkCrypt2]

CkCrypt2_put_CryptAlgorithm $crypt "aes"
# Set the cipher mode to Output Feedback
CkCrypt2_put_CipherMode $crypt "ofb"
CkCrypt2_put_KeyLength $crypt 256

# EncodingMode specifies the encoding of the output for
# encryption, and the input for decryption.
# It may be "hex", "url", "base64", "quoted-printable", or many other choices.
CkCrypt2_put_EncodingMode $crypt "hex"

set ivHex "000102030405060708090A0B0C0D0E0F"
CkCrypt2_SetEncodedIV $crypt $ivHex "hex"

# The secret key must equal the size of the key.  For
# 256-bit encryption, the binary secret key is 32 bytes.
set keyHex "603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4"
CkCrypt2_SetEncodedKey $crypt $keyHex "hex"

# Encrypt a string...
set encStr [CkCrypt2_encryptStringENC $crypt "Popular opinions, on subjects not palpable to sense, are often true, but seldom or never the whole truth. -- John Stuart Mill"]
puts "$encStr"

set decrypt [new_CkCrypt2]

CkCrypt2_put_CryptAlgorithm $decrypt "aes"
CkCrypt2_put_CipherMode $decrypt "ofb"
CkCrypt2_put_KeyLength $decrypt 256
CkCrypt2_put_EncodingMode $decrypt "hex"
CkCrypt2_SetEncodedIV $decrypt $ivHex "hex"
CkCrypt2_SetEncodedKey $decrypt $keyHex "hex"

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

delete_CkCrypt2 $crypt
delete_CkCrypt2 $decrypt