(Swift 3,4,5...) Generate ECDSA Key and Get Details as XML

Demonstrates how to generate an ECC key and gets the parts as XML.

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 ecc = CkoEcc()!

    // Generate a random ECC private key on the secp256k1 curve.
    // Chilkat also supports other curves, such as secp384r1, secp521r1, and secp256r1.

    // Create a Fortuna PRNG and seed it with system entropy.
    // This will be our source of random data for generating the ECC private key.
    let fortuna = CkoPrng()!
    var entropy: String? = fortuna.getEntropy(32, encoding: "base64")
    var success: Bool = fortuna.addEntropy(entropy, encoding: "base64")

    var privKey: CkoPrivateKey? = ecc.genEccKey("secp256k1", prng: fortuna)
    if ecc.lastMethodSuccess != true {
        print("\(ecc.lastErrorText!)")
        return
    }

    // An EC private key has this ASN.1
    // ECPrivateKey ::= SEQUENCE {
    //     version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
    //     privateKey     OCTET STRING,
    //     parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
    //     publicKey  [1] BIT STRING OPTIONAL (This is the ANSI X9.63 public key format.)

    let asn = CkoAsn()!
    success = asn.loadEncoded(privKey!.getPkcs1ENC("base64"), encoding: "base64")
    if success != true {
        print("\(asn.lastErrorText!)")
        return
    }

    let xml = CkoXml()!
    xml.load(asn.asnToXml())

    print("\(xml.getXml()!)")

    // The XML looks like this:
    // <?xml version="1.0" encoding="utf-8" ?>
    // <sequence>
    //     <int>01</int>
    //     <octets>JgJvBG+3wletkJab8iXAkpz0O8/AgWZSpkYVcB7SpnU=</octets>
    //     <contextSpecific tag="0" constructed="1">
    //         <oid>1.3.132.0.10</oid>
    //     </contextSpecific>
    // </sequence>

    // The 32-byte private key is in the octets..
    // Get it as hex.
    let crypt = CkoCrypt2()!
    var privKeyHex: String? = crypt.reEncode(xml.getChildContent("octets"), fromEncoding: "base64", toEncoding: "hex")

    print("EC private key as hex = \(privKeyHex!)")

    privKey = nil

}