improved java api layer, updated to latest libsodium (#98)

bindings/jvm/src/main/java/org/ssohub/crypto/ecc/BaseData.java

@@ -1,5 +1,15 @@
+/*
+ * Copyright (c) 2023, Alden Torres
+ *
+ * Licensed under the terms of the MIT license.
+ * Copy of the license at https://opensource.org/licenses/MIT
+ */
+
 package org.ssohub.crypto.ecc;
 
+/**
+ * @author aldenml
+ */
 public abstract class BaseData implements DataLike {
 
     protected final Data data;

bindings/jvm/src/main/java/org/ssohub/crypto/ecc/Data.java

@@ -30,8 +30,8 @@ public final class Data implements DataLike {
      * Internally perform a copy of the array.
      */
     public Data(byte[] arr, int offset, int length) {
-        if (length < 0)
-            throw new IllegalArgumentException("length should be > 0");
+        if (offset < 0 || length < 0)
+            throw new IllegalArgumentException("both offset and length should be > 0");
         this.arr = Arrays.copyOfRange(arr, offset, offset + length);
     }
 

bindings/jvm/src/main/java/org/ssohub/crypto/ecc/opaque/Opaque.java

@@ -20,6 +20,14 @@ public final class Opaque {
     private Opaque() {
     }
 
+    /**
+     * Returns a randomly generated private and public key pair.
+     * <p>
+     * This is implemented by generating a random "seed", then
+     * calling internally DeriveAuthKeyPair.
+     *
+     * @return a new key pair.
+     */
     public static GenerateAuthKeyPairResult generateAuthKeyPair() {
 
         byte[] privateKey = new byte[ecc_opaque_ristretto255_sha512_Nsk];
@@ -36,6 +44,12 @@ public static GenerateAuthKeyPairResult generateAuthKeyPair() {
         );
     }
 
+    /**
+     * Recover the public key related to the input `privateKey`.
+     *
+     * @param privateKey the private key
+     * @return the corresponding public key.
+     */
     public static OpaquePk recoverPublicKey(OpaqueSk privateKey) {
 
         byte[] publicKey = new byte[ecc_opaque_ristretto255_sha512_Npk];

bindings/jvm/src/main/java/org/ssohub/crypto/ecc/opaque/RegistrationRecord.java

@@ -37,5 +37,7 @@ public Data getMaskingKey() {
         return data.copy(ecc_opaque_ristretto255_sha512_Npk, ecc_opaque_ristretto255_sha512_Nh);
     }
 
-    // TODO: add envelope getter
+    public static RegistrationRecord fromHex(String hex) {
+        return new RegistrationRecord(Data.fromHex(hex));
+    }
 }

bindings/jvm/src/main/java/org/ssohub/crypto/ecc/opaque/RegistrationRequest.java

@@ -35,4 +35,8 @@ public RegistrationRequest(Data data) {
     public R255Element getBlindedMessage() {
         return new R255Element(data);
     }
+
+    public static RegistrationRequest fromHex(String hex) {
+        return new RegistrationRequest(Data.fromHex(hex));
+    }
 }

bindings/jvm/src/main/java/org/ssohub/crypto/ecc/opaque/RegistrationResponse.java

@@ -42,4 +42,8 @@ public R255Element getEvaluatedMessage() {
     public OpaquePk getServerPublicKey() {
         return new OpaquePk(data.copy(ecc_opaque_ristretto255_sha512_Noe, ecc_opaque_ristretto255_sha512_Npk));
     }
+
+    public static RegistrationResponse fromHex(String hex) {
+        return new RegistrationResponse(Data.fromHex(hex));
+    }
 }

bindings/jvm/src/test/java/org/ssohub/crypto/ecc/opaque/OpaqueTest.java

@@ -301,4 +301,15 @@ void testProtocolWithBadPassword() {
         assertNotEquals(0, serverFinishResult.getResult());
         assertNotEquals(clientFinishResult.getSessionKey(), serverFinishResult.getSessionKey());
     }
+
+    @Test
+    void testKeyPairGeneration() {
+
+        GenerateAuthKeyPairResult keyPairResult = Opaque.generateAuthKeyPair();
+        System.out.println("Opaque sk=" + keyPairResult.getPrivateKey().toHex());
+        System.out.println("Opaque pk=" + keyPairResult.getPublicKey().toHex());
+
+        OpaquePk pk = Opaque.recoverPublicKey(keyPairResult.getPrivateKey());
+        assertEquals(keyPairResult.getPublicKey(), pk);
+    }
 }