MIME S/MIME Signing Algorithm Properties

See more MIME Examples

Demonstrates the properties that control S/MIME signing: SigningAlg (the RSA signature scheme, PKCS1-V1_5 or RSASSA-PSS), SigningHashAlg (the message-digest algorithm), Micalg and Protocol (the micalg and protocol parameters of a multipart/signed Content-Type), and UseXPkcs7 (whether historical x-pkcs7 media-type names are used). The properties are configured before creating a detached signature.

func chilkatTest() {
    var success: Bool = false

    let mime = CkoMime()!
    success = mime.setBody(fromPlainText: "This message will be signed.")
    if success == false {
        print("\(mime.lastErrorText!)")
        return
    }

    //  SigningAlg is the RSA signature scheme.  The default is PKCS1-V1_5; set RSASSA-PSS (or pss) for
    //  RSASSA-PSS.
    mime.signingAlg = "PKCS1-V1_5"

    //  SigningHashAlg is the message-digest algorithm.  The default is sha256.
    mime.signingHashAlg = "sha256"

    //  Micalg and Protocol are the micalg and protocol parameters written into a multipart/signed
    //  Content-Type header field.  They are normally set automatically, but can be controlled here.
    mime.micalg = "sha-256"
    mime.protocol = "application/pkcs7-signature"

    //  UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
    mime.useXPkcs7 = false

    //  Load a signing certificate (with private key access) from a PFX.  The PFX password should come
    //  from a secure source rather than being hard-coded.
    var pfxPassword: String? = "myPfxPassword"
    let cert = CkoCert()!
    success = cert.loadPfxFile(path: "qa_data/signer.pfx", password: pfxPassword)
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    //  Create the detached signature using the algorithms configured above.
    success = mime.addDetachedSignature(cert: cert)
    if success == false {
        print("\(mime.lastErrorText!)")
        return
    }

    print("Signed with SigningAlg=\(mime.signingAlg!) SigningHashAlg=\(mime.signingHashAlg!)")

}