(Lianja) 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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//  This example requires the Chilkat Crypt API to have been previously unlocked.
//  See Unlock Chilkat Crypt for sample code.

loCrypt = createobject("CkCrypt2")

//  Use public-key cryptography for encryption.
loCrypt.CryptAlgorithm = "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.
loCert = createobject("CkCert")
llSuccess = loCert.LoadFromFile("qa_data/certs/testCert.cer")
if (llSuccess <> .T.) then
    ? loCert.LastErrorText
    release loCrypt
    release loCert
    return
endif

llSuccess = loCrypt.SetEncryptCert(loCert)
if (llSuccess <> .T.) then
    ? loCrypt.LastErrorText
    release loCrypt
    release loCert
    return
endif

//  Indicate the underlying bulk encryption algorithm to be used:
loCrypt.Pkcs7CryptAlg = "aes"
loCrypt.KeyLength = 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 .T. to
//  use RSAES_OAEP.  (We'll leave it set at the default value of .F.)
loCrypt.OaepPadding = .F.

//  Everything is specified.  Now just encrypt...
//  The output is PKCS7 in binary DER format.
llSuccess = loCrypt.CkEncryptFile("qa_data/hamlet.xml","qa_output/hamlet.p7")
if (llSuccess <> .T.) then
    ? loCrypt.LastErrorText
    release loCrypt
    release loCert
    return
endif

? "Finished."


release loCrypt
release loCert