(Swift 3,4,5...) Ed25519 Sign and Verify

Demonstrates how to create an Ed25519 signature, and then to verify it.

Note: This example requires Chilkat v9.5.0.83 or greater.

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

    var privKeyHex: String? = "1498b5467a63dffa2dc9d9e069caf075d16fc33fdd4c3b01bfadae6433767d93"
    var pubKeyHex: String? = "b7a3c12dc0c8c748ab07525b701122b88bd78f600c76342d27f25e5f92444cde"

    let privKey = CkoPrivateKey()!
    // This example shows only one way of loading an Ed25519 private key.
    // Chilkat can load other formats (JWK, PEM, ASN.1 DER, etc.)  
    // You may do so by calling LoadAnyFormat or LoadAnyFormatFile.
    var success: Bool = privKey.loadEd25519(privKeyHex, pubKey: pubKeyHex)
    if success == false {
        print("\(privKey.lastErrorText!)")
        return
    }

    // The data to be signed...
    let bd = CkoBinData()!
    bd.append("Message for Ed25519 signing", charset: "utf-8")

    let eddsa = CkoEdDSA()!
    var hexSig: String? = eddsa.signBdENC(bd, encoding: "hexlower", privkey: privKey)

    print("signature = \(hexSig!)")

    // The expected output is: 6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08

    // Verify the signature..
    let pubKey = CkoPublicKey()!
    success = pubKey.loadEd25519(pubKeyHex)
    if success == false {
        print("\(pubKey.lastErrorText!)")
        return
    }

    var bVerified: Bool = eddsa.verifyBdENC(bd, encodedSig: hexSig, enocding: "hexlower", pubkey: pubKey)
    if bVerified == false {
        print("\(eddsa.lastErrorText!)")
        print("Failed to verify the signature.")
        return
    }

    print("The Ed25519 signature is verified!")

}