MIME S/MIME Encryption Algorithm Properties

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Demonstrates the properties that control S/MIME encryption: Pkcs7CryptAlg (the symmetric content-encryption algorithm), Pkcs7KeyLength (the content-encryption key length in bits), OaepPadding (whether RSAES-OAEP key transport is used instead of RSAES-PKCS1-v1_5), and the OAEP hash settings OaepHash and OaepMgfHash. The properties are configured before calling Encrypt.

local chilkat = require("chilkat")

local mime = chilkat.Mime.new()
local success = mime:set_body_from_plain_text("This message will be encrypted.")
if not success then
    print(mime.last_error_text)
    return
end

-- Pkcs7CryptAlg is the symmetric content-encryption algorithm.  Supported values are aes, aes-gcm,
-- des, 3des, and rc2.  The default is aes.
mime.pkcs7_crypt_alg = "aes"

-- Pkcs7KeyLength is the content-encryption key length in bits.  The default is 128.
mime.pkcs7_key_length = 256

-- OaepPadding selects the RSA key-transport padding.  The default is false (RSAES-PKCS1-v1_5).
-- Set true to use RSAES-OAEP, in which case the OAEP hash settings apply.
mime.oaep_padding = true
mime.oaep_hash = "sha256"
mime.oaep_mgf_hash = "sha256"

-- Load the recipient certificate (public key is sufficient for encrypting).
local cert = chilkat.Cert.new()
success = cert:load_from_file("qa_data/recipient.cer")
if not success then
    print(cert.last_error_text)
    return
end

-- Encrypt using the algorithm settings configured above.
success = mime:encrypt(cert)
if not success then
    print(mime.last_error_text)
    return
end

print("Encrypted with " .. mime.pkcs7_crypt_alg .. " " .. mime.pkcs7_key_length .. "-bit key.")