(Swift 2) Get Public Key from CSR

Demonstrates how to get the public key from a CSR.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // This requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    let pem = CkoPem()

    // No password is required.  Pass an empty password string..
    var noPassword: String? = ""
    var success: Bool = pem.LoadPemFile("qa_data/csr/csr2.pem", password: noPassword)
    if success != true {
        print("\(pem.LastErrorText)")
        return
    }

    var strBase64: String? = pem.GetEncodedItem("csr", itemSubType: "", encoding: "base64", index: 0)

    let asn = CkoAsn()
    success = asn.LoadEncoded(strBase64, encoding: "base64")
    if success != true {
        print("\(asn.LastErrorText)")
        return
    }

    // Convert the ASN.1 to XML.
    let xml = CkoXml()
    success = xml.LoadXml(asn.AsnToXml())
    print("\(xml.GetXml())")
    print("----")

    var strModulusHex: String? = xml.GetChildContent("bits")
    print("strModulusHex = \(strModulusHex!)")
    print("----")

    // We need the modulus as base64.
    let bd = CkoBinData()
    bd.AppendEncoded(strModulusHex, encoding: "hex")
    var modulus64: String? = bd.GetEncoded("base64")
    print("modulus64 = \(modulus64!)")
    print("----")

    // Build the XML for the public key.
    let xmlPubKey = CkoXml()
    xmlPubKey.Tag = "RSAPublicKey"
    xmlPubKey.UpdateChildContent("Modulus", value: modulus64)
    // The RSA exponent will always be decimal 65537 (base64 = AQAB)
    xmlPubKey.UpdateChildContent("Exponent", value: "AQAB")

    print("RSA public key as XML:")
    print("\(xmlPubKey.GetXml())")
    print("----")

    // Load the XML into a Chilkat public key object.
    let pubkey = CkoPublicKey()
    success = pubkey.LoadFromString(xmlPubKey.GetXml())
    if success != true {
        print("\(pubkey.LastErrorText)")
        return
    }

    // Show the public key as PEM.
    var preferPkcs1: Bool = true
    print("\(pubkey.GetPem(preferPkcs1))")

}