(Swift 3,4,5...) Verify JWT with EdDSA / Ed25519 Signature

Note: This example requires Chilkat v9.5.0.84 or greater.

Demonstrates how to verify a JWT that was signed using an Ed25519 private key.

This example verifies the EdDSA signature. It also does the following:

• Checks to see if the time constraints ("nbf" and "exp") are valid.
• Recovers the original JOSE header.
• Recovers the original data.

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func chilkatTest() {
    // Demonstrates how to verify a JWT with an EdDSA/Ed25519 Signature
    // *** Requires Chilkat v9.5.0.84 or greater.

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

    // Use this Ed25519 public key for verification

    var jsonPubKey: String? = "{\"kty\": \"OKP\",\"alg\": \"EdDSA\",\"crv\": \"Ed25519\",\"x\": \"11qYAYKxCrfVS_7TyWQHOg7hcvPapiMlrwIaaPcHURo\"}"

    let pubKey = CkoPublicKey()!
    var success: Bool = pubKey.load(from: jsonPubKey)
    if success == false {
        print("\(pubKey.lastErrorText!)")
        return
    }

    let jwt = CkoJwt()!
    var token: String? = "eyJhbGciOiJFZERTQSJ9.RXhhbXBsZSBvZiBFZDI1NTE5IHNpZ25pbmc.hgyY0il_MGCjP0JzlnLWG1PPOt7-09PGcvMg3AIbQR6dWbhijcNR4ki4iylGjg5BhVsPt9g7sVvpAr_MuM0KAg"

    // First verify the signature.
    var sigVerified: Bool = jwt.verifyJwtPk(token, key: pubKey)
    print("verified: \(sigVerified)")

    if sigVerified == false {
        print("\(jwt.lastErrorText!)")
        return
    }

    // Let's see if the time constraints, if any, are valid.
    // The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
    // If the current system time is before the "nbf" time, or after the "exp" time,
    // then IsTimeValid will return false/0.
    // Also, we'll allow a leeway of 60 seconds to account for any clock skew.
    // Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
    var leeway: Int = 60
    var bTimeValid: Bool = jwt.isTimeValid(token, leeway: leeway)
    print("time constraints valid: \(bTimeValid)")

    // Recover the original data (the payload).
    var payload: String? = jwt.getPayload(token)
    print("\(payload!)")

    // Recover the original JOSE header in the same way:
    var joseHeader: String? = jwt.getHeader(token)
    print("\(joseHeader!)")

}