(Swift 3,4,5...) Get a Certificate's Key Size

Demonstrates how to get the RSA key size of a certificate (for example, 1024-bit, 2048-bit, etc.)

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

func chilkatTest() {
    // For this example, I have a certificate in raw base64 format (not PEM),
    // that looks like this:  "MIIGkDCCBHigAwIBAgIUMDA ... s/iqLsLA=="
    let sbCertBase64 = CkoStringBuilder()!
    var success: Bool = sbCertBase64.loadFile("qa_data/certs/base64Cert.txt", charset: "utf-8")

    let cert = CkoCert()!
    success = cert.load(fromBase64: sbCertBase64.getAsString())
    if success != true {
        print("\(cert.lastErrorText!)")
        return
    }

    // Get the public key.
    var pubKey: CkoPublicKey? = cert.exportPublicKey()
    if cert.lastMethodSuccess != true {
        print("\(cert.lastErrorText!)")
        return
    }

    // In Chilkat version v9.5.0.67, the KeySize property was added.
    var numBits: Int = pubKey!.keySize.intValue
    print("Number of bits = \(numBits)")

    // If using an older version of Chilkat, the key size can be obtained like this:
    let xml = CkoXml()!
    xml.load(pubKey!.getXml())

    let binDat = CkoBinData()!
    binDat.appendEncoded(xml.getChildContent("Modulus"), encoding: "base64")

    numBits = 8 * binDat.numBytes.intValue
    print("Number of bits = \(numBits)")

    pubKey = nil

}