Swift

Generate ECDSA Key and Get Details as XML

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

func chilkatTest() {
    var success: Bool = false

    // 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(numBytes: 32, encoding: "base64")
    success = fortuna.addEntropy(entropy: entropy, encoding: "base64")

    let privKey = CkoPrivateKey()!
    success = ecc.genKey(curveName: "secp256k1", prng: fortuna, privKey: privKey)
    if success == false {
        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(asnContent: privKey.getPkcs1ENC(encoding: "base64"), encoding: "base64")
    if success != true {
        print("\(asn.lastErrorText!)")
        return
    }

    let xml = CkoXml()!
    xml.load(xmlData: 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(data: xml.getChildContent(tagPath: "octets"), fromEncoding: "base64", toEncoding: "hex")

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

}