Swift

Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using the private key associated with a certificate on a smart card. Swift

func chilkatTest() {
    var success: Bool = false

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

    // Load the certificate from a smart card.
    let cert = CkoCert()!

    // Set the smarcard PIN prior to loading
    cert.smartCardPin = "123456"

    // Detect the connected smartcard or USB security token and load the default certificate.
    success = cert.load(fromSmartcard: "")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    // Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
    // such as selecting a certificate if the card contains multiple certificates with private keys,
    // or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

    // Create the JWS Protected Header
    let jwsProtHdr = CkoJsonObject()!

    if cert.isEcdsa() == true {
        jwsProtHdr.appendString(name: "alg", value: "ES256")
    }
    else {
        jwsProtHdr.appendString(name: "alg", value: "RS256")
    }

    let jws = CkoJws()!

    // Set the protected header:
    var signatureIndex: Int = 0
    jws.setProtectedHeader(index: signatureIndex, json: jwsProtHdr)

    // Provide the private key via the certificate.
    // This requires Chilkat v11.5.0 or greater.
    jws.setSigningCert(index: signatureIndex, cert: cert)

    // Set the payload.
    var bIncludeBom: Bool = false
    var payloadStr: String? = "In our village, folks say God crumbles up the old moon into stars."
    jws.setPayload(payload: payloadStr, charset: "utf-8", includeBom: bIncludeBom)

    // Create the JWS
    // By default, the compact serialization is used.
    var jwsCompact: String? = jws.create()
    if jws.lastMethodSuccess == false {
        print("\(jws.lastErrorText!)")
        return
    }

    print("JWS: \(jwsCompact!)")

    // sample output:
    // JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

    // Now load the JWS, validate, and recover the original text.
    let jws2 = CkoJws()!

    // Load the JWS.
    success = jws2.load(jwsStr: jwsCompact)

    let pubKey = CkoPublicKey()!
    cert.getPublicKey(pubKey: pubKey)

    // Set the public key used for validation.
    signatureIndex = 0
    jws2.setPublicKey(index: signatureIndex, pubKey: pubKey)

    // Validate the 1st (and only) signature at index 0..
    var v: Int = jws2.validate(index: signatureIndex).intValue
    if v < 0 {
        // Perhaps Chilkat was not unlocked or the trial expired..
        print("Method call failed for some other reason.")
        print("\(jws2.lastErrorText!)")
        return
    }

    if v == 0 {
        print("Invalid signature.  The key was incorrect, the JWS was invalid, or both.")
        return
    }

    // If we get here, the signature was validated..
    print("Signature validated.")

    // Recover the original content:
    print("\(jws2.getPayload(charset: "utf-8")!)")

    // Examine the protected header:

    let joseHeader = CkoJsonObject()!
    success = jws2.getProtectedH(index: signatureIndex, json: joseHeader)
    if success == false {
        print("\(jws2.lastErrorText!)")
        return
    }

    joseHeader.emitCompact = false

    print("Protected (JOSE) header:")
    print("\(joseHeader.emit()!)")

    // Output:

    // 	Signature validated.
    // 	In our village, folks say God crumbles up the old moon into stars.
    // 	Protected (JOSE) header:
    // 	{ 
    // 	  "alg": "RS256"
    // 	}

}