Add java21-features module: runnable demos and captured output for the ankurm.com java21-features article

2026-10-20 17:13:59 +00:00
parent 5a076c826f
commit c3cc57f482
33 changed files with 354 additions and 0 deletions
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+import javax.crypto.*;
+import java.security.*;
+import java.util.Arrays;
+
+/** JEP 452 (final): Key Encapsulation Mechanism API, with the DHKEM implementation that ships in 21. */
+public class KemDemo {
+    public static void main(String[] args) throws Exception {
+        KeyPairGenerator g = KeyPairGenerator.getInstance("X25519");
+        KeyPair kp = g.generateKeyPair();
+        KEM kem = KEM.getInstance("DHKEM");
+        KEM.Encapsulator enc = kem.newEncapsulator(kp.getPublic());
+        KEM.Encapsulated e = enc.encapsulate();
+        SecretKey sender = e.key();
+        SecretKey receiver = kem.newDecapsulator(kp.getPrivate()).decapsulate(e.encapsulation());
+        System.out.println("algorithm       : " + kem.getAlgorithm());
+        System.out.println("secrets equal   : " + Arrays.equals(sender.getEncoded(), receiver.getEncoded()));
+        System.out.println("secret length   : " + sender.getEncoded().length + " bytes");
+        System.out.println("ciphertext length: " + e.encapsulation().length + " bytes");
+    }
+}