(Tcl) Encrypt File using X.509 Certificate using AES in CBC Mode

Demonstrates how to encrypt a file using an X.509 Certificate's public key, where the underlying bulk encryption algorithm is 128-bit AES in CBC mode. (The underlying bulk encryption algorithm can be specified to be other algorithms/strengths.)

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load ./chilkat.dll

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

set crypt [new_CkCrypt2]

# Use public-key cryptography for encryption.
CkCrypt2_put_CryptAlgorithm $crypt "pki"

# Get an X.509 certificate to use for encrypting.
# Note: Chilkat provides many different ways of loading a certificate, from many different formats,
# or if on Windows, from the installed certificates on the system.
# This example simply loads a certificate from a file.
# Also, for encryption, only the public key is needed.  Digital certificates embed the public key
# within the X.509 format itself.  Therefore, if you have a certificate, you also have the public key.
set cert [new_CkCert]

set success [CkCert_LoadFromFile $cert "qa_data/certs/testCert.cer"]
if {$success != 1} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    exit
}

set success [CkCrypt2_SetEncryptCert $crypt $cert]
if {$success != 1} then {
    puts [CkCrypt2_lastErrorText $crypt]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    exit
}

# Indicate the underlying bulk encryption algorithm to be used:
CkCrypt2_put_Pkcs7CryptAlg $crypt "aes"
CkCrypt2_put_KeyLength $crypt 128

# Note: When doing public-key encryption the underlying bulk symmetric cipher mode will always be CBC. (at least with Chilkat...)

# There's one last option that could be set.  If is the RSA encryption encryption/padding scheme. 
# By default, RSAES_PKCS1-V1_5 is used.  If desired, the OaepPadding property could be set to 1 to
# use RSAES_OAEP.  (We'll leave it set at the default value of 0)
CkCrypt2_put_OaepPadding $crypt 0

# Everything is specified.  Now just encrypt...
# The output is PKCS7 in binary DER format.
set success [CkCrypt2_CkEncryptFile $crypt "qa_data/hamlet.xml" "qa_output/hamlet.p7"]
if {$success != 1} then {
    puts [CkCrypt2_lastErrorText $crypt]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    exit
}

puts "Finished."

delete_CkCrypt2 $crypt
delete_CkCert $cert