(Tcl) AES-CMAC

Demonstrates using the AES-CMAC algorithm, which is a keyed hash function similar to HMAC and Poly1305.

Note: Chilkat added AES-CMAC in version 9.5.0.95.

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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 MAC algorithm to AES-CMAC
CkCrypt2_put_MacAlgorithm $crypt "aes-cmac"

# AES-CMAC always uses a 16-byte (128-bit) MAC key.
set keyHex "2b7e151628aed2a6abf7158809cf4f3c"
set success [CkCrypt2_SetMacKeyEncoded $crypt $keyHex "hex"]

# Let's compute the AES-CMAC for the test vector at https://www.rfc-editor.org/rfc/rfc4493#appendix-A
# Here we have 64 bytes in hex representation.
set messageBytes "6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710"

set bd [new_CkBinData]

CkBinData_AppendEncoded $bd $messageBytes "hex"

# Compute the AES-CMAC for the bytes contained in bd and return the AES-CMAC in hex representation.
CkCrypt2_put_EncodingMode $crypt "hex_lower"
set cmac [CkCrypt2_macBdENC $crypt $bd]
puts "$cmac"
# Output should be: 51f0bebf7e3b9d92fc49741779363cfe

# Now do the same for a string:
set plainText "'Twas brillig, and the slithy toves\nDid gyre and gimble in the wabe:\nAll mimsy were the borogoves,\nAnd the mome raths outgrabe."
set encTag [CkCrypt2_macStringENC $crypt $plainText]
puts "$encTag"

# Output should be: 4fca1fcbd265048d247f99ab57fa3ceb

delete_CkCrypt2 $crypt
delete_CkBinData $bd