finish out the base crypto test suite and include the DES algo;

tests/crypto/DES_Crypto_Test.cpp

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Digital Voice Modem - Test Suite
+ * GPLv2 Open Source. Use is subject to license terms.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ *  Copyright (C) 2026 Bryan Biedenkapp, N2PLL
+ *
+ */
+#include "host/Defines.h"
+#include "common/DESCrypto.h"
+#include "common/Log.h"
+#include "common/Utils.h"
+
+using namespace crypto;
+
+#include <catch2/catch_test_macros.hpp>
+#include <stdlib.h>
+#include <time.h>
+
+TEST_CASE("DES Crypto Test", "[des][crypto_test]") {
+    bool failed = false;
+
+    INFO("DES Crypto Test");
+
+    srand((unsigned int)time(NULL));
+
+    // key (K) - DES uses 8-byte (64-bit) keys
+    uint8_t K[8] = 
+    {
+        0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF
+    };
+
+    // message - DES operates on 8-byte blocks
+    uint8_t message[8] = 
+    {
+        0x90, 0x56, 0x00, 0x00, 0x2D, 0x75, 0xE6, 0x8D
+    };
+
+    // perform crypto
+    DES* des = new DES();
+
+    Utils::dump(2U, "DES_Crypto_Test, Message", message, 8);
+
+    uint8_t* crypted = des->encryptBlock(message, K);
+    Utils::dump(2U, "DES_Crypto_Test, Encrypted", crypted, 8);
+
+    uint8_t* decrypted = des->decryptBlock(crypted, K);
+    Utils::dump(2U, "DES_Crypto_Test, Decrypted", decrypted, 8);
+
+    for (uint32_t i = 0; i < 8U; i++) {
+        if (decrypted[i] != message[i]) {
+            ::LogError("T", "DES_Crypto_Test, INVALID AT IDX %d", i);
+            failed = true;
+        }
+    }
+
+    delete des;
+    REQUIRE(failed==false);
+}