Flow 14 --- In-Memory JWE / JWS Quick-start

/*
 * Copyright 2025 ANKATech Solutions Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package co.ankatech.ankasecure.sdk.examples;

import co.ankatech.ankasecure.sdk.AuthenticatedSdk;
import co.ankatech.ankasecure.sdk.exception.AnkaSecureSdkException;
import co.ankatech.ankasecure.sdk.model.*;

import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.Properties;

import static co.ankatech.ankasecure.sdk.examples.ExampleUtil.*;

/**
 * Scenario 14 — In-Memory Post-Quantum Crypto (Compact JWE/JWS).
 *
 * <p>This scenario performs an <em>entirely file-less</em> encryption &rarr; decryption
 * and signing &rarr; verification cycle with post-quantum algorithms:</p>
 * <ol>
 *   <li>Resolve a pre-provisioned HQC-128 key for encryption and decryption
 *       (the SDK is data-plane-only — it does not create keys).</li>
 *   <li>Resolve a pre-provisioned SLH-DSA-SHA2-128S key for signing and verification.</li>
 *   <li>Encrypt a UTF-8 message into a Compact JWE token and decrypt it
 *       back to bytes.</li>
 *   <li>Sign the same bytes, producing a Compact JWS token, and verify
 *       that signature.</li>
 * </ol>
 *
 * <p>All artefacts remain in memory; nothing touches the disk.</p>
 *
 * @see ExampleUtil
 * @see ExamplePlaygroundKeys
 * @see AuthenticatedSdk
 */
public final class ExampleScenario14 {

    /** No instantiation &mdash; this class only exposes {@link #main(String[])}. */
    private ExampleScenario14() { }

    /**
     * Runs the in-memory post-quantum crypto scenario.
     *
     * <p>Loads CLI properties, authenticates against ANKASecure&copy;,
     * and delegates to the scenario logic. On any unrecoverable error
     * the JVM terminates via
     * {@link ExampleUtil#fatal(String, Throwable)}.</p>
     *
     * @param args command-line arguments (ignored)
     */
    public static void main(final String[] args) {

        System.out.println("===== SCENARIO 14 START =====");
        System.out.println("""
                Purpose :
                  * 100 % in-memory encrypt ➜ decrypt and sign ➜ verify.
                  * Operates on pre-provisioned playground keys.
                Steps   :
                  1) Resolve pre-provisioned HQC-128 key (encrypt/decrypt).
                  2) Resolve pre-provisioned SLH-DSA-SHA2-128S key (sign/verify).
                  3) Encrypt plaintext -> Compact JWE.
                  4) Decrypt Compact JWE.
                  5) Sign plaintext -> Compact JWS.
                  6) Verify Compact JWS signature.
                --------------------------------------------------------------""");

        try {
            Properties            props      = loadProperties();
            AuthenticatedSdk      sdk        = authenticate(props);
            ExamplePlaygroundKeys playground = ExamplePlaygroundKeys.from(props, sdk);

            runScenario(sdk, playground);

        } catch (Exception ex) {
            fatal("Scenario 14 failed", ex);
        }

        System.out.println("===== SCENARIO 14 END =====");
    }

    /* ====================================================================== */

    /**
     * Executes the complete in-memory flow on pre-provisioned keys.
     */
    private static void runScenario(final AuthenticatedSdk sdk,
                                    final ExamplePlaygroundKeys playground) throws AnkaSecureSdkException {

        /* 0 ── plaintext -------------------------------------------------- */
        byte[] plaintext = "Hello PQC world – Scenario 14".getBytes(StandardCharsets.UTF_8);
        System.out.println("[0] Plaintext prepared      (" + plaintext.length + " bytes)");

        /* 1 ── resolve pre-provisioned HQC-128 key (encrypt/decrypt) ----- */
        final String encKid = playground.kidForAlgorithm("HQC-128");
        System.out.println("[1] Using pre-provisioned key -> kid = " + encKid);

        /* 2 ── resolve pre-provisioned SLH-DSA-SHA2-128S key (sign/verify) */
        final String signKid = playground.kidForAlgorithm("SLH-DSA-SHA2-128S");
        System.out.println("[2] Using pre-provisioned key -> kid = " + signKid);

        /* 3 ── Encrypt (Compact JWE) ------------------------------------ */
        EncryptResult encRes = sdk.encrypt(encKid, plaintext);
        String jwe = encRes.getJweToken();
        System.out.println("[3] JWE created             (length = " + jwe.length() + ")");
        printEncryptMeta(encRes);

        /* 4 ── Decrypt --------------------------------------------------- */
        DecryptResult decRes = sdk.decrypt(jwe);
        byte[] recovered = decRes.getDecryptedData();
        System.out.println("[4] Decrypted text          : " +
                new String(recovered, StandardCharsets.UTF_8));
        printDecryptMeta(decRes);

        /* 5 ── Sign (Compact JWS) --------------------------------------- */
        SignResult sigRes = sdk.sign(signKid, plaintext);
        String jws = sigRes.getJwsToken();
        System.out.println("[5] JWS created             (length = " + jws.length() + ")");
        printSignMeta(sigRes);

        /* 6 ── Verify ---------------------------------------------------- */
        VerifySignatureResult verRes = sdk.verifySignature(jws);
        System.out.println("[6] Signature valid?        -> " + verRes.isValid());
        printVerifyMeta(verRes);

        /* 7 ── Integrity check ----------------------------------------- */
        boolean match = Objects.equals(
                new String(plaintext, StandardCharsets.UTF_8),
                new String(recovered, StandardCharsets.UTF_8));
        System.out.println(match
                ? "SUCCESS - round-trip data matches."
                : "FAILURE - data mismatch!");
    }
}