Lua Requires Chilkat v11.0.0+

IMAP Download and Verify Signed MIME

See more IMAP Examples

Downloads the original MIME of a digitally signed email and saves the .p7s signature along with other MIME parts. It then imports the email into a Chilkat email object to unwrap the S/MIME and verify the signature, and subsequently saves the attachments if they haven't been saved already. Lua

local chilkat = require("chilkat")

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

local imap = chilkat.Imap.new()

-- Connect to an IMAP server.
-- Use TLS
imap.ssl = true
imap.port = 993
local success = imap:connect("imap.example.com")
if not success then
    print(imap.last_error_text)
    return
end

success = imap:login("myLogin", "myPassword")
if not success then
    print(imap.last_error_text)
    return
end

-- Select an IMAP mailbox
success = imap:select_mailbox("Inbox")
if not success then
    print(imap.last_error_text)
    return
end

-- Download the 1st email (as MIME) in the Inbox by sequence number.
local sbMime = chilkat.StringBuilder.new()
success = imap:fetch_single_as_mime_sb(1, false, sbMime)
if not success then
    print(imap.last_error_text)
    return
end

-- Load it into a MIME object and check to see if it is signed
local mime = chilkat.Mime.new()
mime:load_mime_sb(sbMime)
local alreadySavedParts = false
if mime:contains_signed_parts() then
    -- This will save the .p7s and other parts...
    local st = chilkat.StringTable.new()
    success = mime:parts_to_files("c:/temp/qa_output", st)
    if success then
        local numFiles = st.count
        local i = 0
        while i < numFiles do
            print("Created: " .. st:string_at(i))
            i = i + 1
        end

        alreadySavedParts = true
    end
end

-- Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
local email = chilkat.Email.new()
email:set_from_mime_sb(sbMime)

if email.received_signed then
    print("This email was signed.")

    -- Check to see if the signatures were verified.
    if email.signatures_valid then
        print("Digital signature(s) verified.")
        print("Signer: " .. email.signed_by)

        -- The certificate used for signing may be obtained
        -- by calling email.LastSignerCert.  Index 0 is the first signer.
        local cert = chilkat.Cert.new()
        success = email:last_signer_cert(0, cert)
        if not success then
            print("Failed to get signing certificate object.")
        else
            print("Signing cert: " .. cert.subject_cn)
        end
    else
        print("Digital signature verification failed.")
    end
else
    print("This email was not signed.")
end

if not alreadySavedParts then
    email:save_all_attachments("c:/temp/qa_output")
end