Use Certificate and Private Key PEM Files to Create a Digital Signature

Demonstrates how to load a digital certificate from a PEM file, load it's corresponding private key from a PEM file, save the private key to a key container (if necessary), link the certificate to the key container, and use it to create a digital signature.

Download Chilkat Crypt ActiveX

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
Set outFile = fso.CreateTextFile("output.txt", True)

set cert = CreateObject("Chilkat.Cert")

'  Load the cert from a PEM file;
cert.LoadFromFile "cert.pem"

set pkey = CreateObject("Chilkat.PrivateKey")

'  Load the private key from an RSA PEM file:
pkey.LoadPemFile "pkey_rsa.pem"

'  If the "chilkat" key container does not already exist,
'  we'll create it and import the private key:
set container = CreateObject("Chilkat.KeyContainer")
needPrivateKeyAccess = 1
machineKeyset = 0
If (container.OpenContainer("chilkat",needPrivateKeyAccess,machineKeyset) = 0) Then

    '  We need to create the key container and import
    '  the private key:
    success = container.CreateContainer("chilkat",machineKeyset)
    If (success = 1) Then
        isKeyExchangePair = 0
        success = container.ImportPrivateKey(pkey,isKeyExchangePair)
        If (success = 0) Then
            outFile.WriteLine("Failed to import private key into key container")
            WScript.Quit
        End If

    Else
        outFile.WriteLine("Failed to create key container")
        WScript.Quit
    End If

End If

'  At this point, the key container contains the private key.
'  Link the certificate with the key container:
bForSigning = 1
success = cert.LinkPrivateKey("chilkat",machineKeyset,bForSigning)
If (success = 0) Then
    outFile.WriteLine("Failed to link certificate with key container")
    WScript.Quit
End If

'  Use Chilkat Crypt (a non-freeware component) to create
'  a digital signature using the certificate w/ private key:
set crypt = CreateObject("Chilkat.Crypt2")

'  Any string argument automatically begins the 30-day trial.
success = crypt.UnlockComponent("30-day trial")
If (success <> 1) Then
    MsgBox "Crypt component unlock failed"
    WScript.Quit
End If

'  Tell the crypt component to use this cert.
crypt.SetSigningCert cert

'  We can sign any type of file, creating a .p7s as output:
success = crypt.CreateP7S("license.rtf","license.p7s")
If (success = 0) Then
    MsgBox crypt.LastErrorText

    WScript.Quit
End If

outFile.WriteLine(crypt.LastErrorText)

'  Verify and restore the original file:
crypt.SetVerifyCert cert

success = crypt.VerifyP7S("license.rtf","license.p7s")
If (success = 0) Then
    MsgBox crypt.LastErrorText

    WScript.Quit
End If

MsgBox "Success!"

'  The Chilkat Certificate, Certificate Store, Private Key,
'  Public Key, and Key Container classes / objects are freeware.

'  They are used by and included with the Chilkat Email,
'  Crypt, S/MIME, and other commercial Chilkat components.

outFile.Close