Add known answer tests (KATs) for Ascon-AEAD128

Signed-off-by: Anjan Roy <[email protected]>

tests/kat_ascon_aead128.cpp

@@ -0,0 +1,72 @@
+#include "ascon/aead/ascon_aead128.hpp"
+#include "test_helper.hpp"
+#include <fstream>
+#include <gtest/gtest.h>
+
+TEST(AsconAEAD128, KnownAnswerTests)
+{
+  using namespace std::literals;
+
+  const std::string kat_file = "./kats/ascon_aead128.kat";
+  std::fstream file(kat_file);
+
+  while (true) {
+    std::string count0;
+
+    if (!std::getline(file, count0).eof()) {
+      std::string key0;
+      std::string nonce0;
+      std::string pt0;
+      std::string ad0;
+      std::string ct0;
+
+      std::getline(file, key0);
+      std::getline(file, nonce0);
+      std::getline(file, pt0);
+      std::getline(file, ad0);
+      std::getline(file, ct0);
+
+      auto key1 = std::string_view(key0);
+      auto nonce1 = std::string_view(nonce0);
+      auto pt1 = std::string_view(pt0);
+      auto ad1 = std::string_view(ad0);
+      auto ct1 = std::string_view(ct0);
+
+      auto key2 = key1.substr(key1.find("="sv) + 2, key1.size());
+      auto nonce2 = nonce1.substr(nonce1.find("="sv) + 2, nonce1.size());
+      auto pt2 = ((pt1.find("="sv) + 2) > pt1.size()) ? ""sv : pt1.substr(pt1.find("="sv) + 2, pt1.size());
+      auto ad2 = ((ad1.find("="sv) + 2) > ad1.size()) ? ""sv : ad1.substr(ad1.find("="sv) + 2, ad1.size());
+      auto ct2 = ct1.substr(ct1.find("="sv) + 2, ct1.size());
+
+      auto key = hex_to_bytes(key2);
+      auto nonce = hex_to_bytes(nonce2);
+      auto pt = hex_to_bytes(pt2);
+      auto ad = hex_to_bytes(ad2);
+      auto ct = hex_to_bytes(ct2); // cipher text + tag
+
+      auto key_span = std::span<const uint8_t, ascon_aead128::KEY_BYTE_LEN>(key);
+      auto nonce_span = std::span<const uint8_t, ascon_aead128::NONCE_BYTE_LEN>(nonce);
+
+      std::vector<uint8_t> computed_ct(pt.size());
+      std::array<uint8_t, ascon_aead128::TAG_BYTE_LEN> computed_tag{};
+      std::vector<uint8_t> computed_pt(computed_ct.size());
+
+      ascon_aead128::encrypt(key_span, nonce_span, ad, pt, computed_ct, computed_tag);
+      const auto is_decrypted = ascon_aead128::decrypt(key_span, nonce_span, ad, computed_ct, computed_pt, computed_tag);
+
+      EXPECT_TRUE(is_decrypted);
+
+      auto ct_span = std::span(ct);
+
+      EXPECT_TRUE(std::ranges::equal(ct_span.first(pt.size()), computed_ct));
+      EXPECT_TRUE(std::ranges::equal(ct_span.last(computed_tag.size()), computed_tag));
+
+      std::string empty_line;
+      std::getline(file, empty_line);
+    } else {
+      break;
+    }
+  }
+
+  file.close();
+}