1 files changed, 66 insertions, 34 deletions

diff --git a/src/tb/tb_aes.v b/src/tb/tb_aes.v
index 6561b4d..84be6a8 100644
--- a/src/tb/tb_aes.v
+++ b/src/tb/tb_aes.v
@@ -429,11 +429,64 @@ module tb_aes();
 
 
   //----------------------------------------------------------------
-  // nist_fips_tests()
+  // single_block_mangle_test()
   //
-  // Perform tests based on NIST FIPS-197 test vectors.
+  // Perform single block test, but try to mangle the operation
+  // by changing from encryption to decryption mid-processing.
+  // This should cause errors unless changes to config during
+  // processing.
+  //----------------------------------------------------------------
+  task single_block_mangle_test(input [7 : 0]  tc_number,
+                               input [255 : 0] key,
+                               input [127 : 0] block,
+                               input [127 : 0] expected);
+    begin
+      $display("*** TC %0d mangle test started.", tc_number);
+      tc_ctr = tc_ctr + 1;
+
+      init_key(key, AES_128_BIT_KEY);
+      write_block(block);
+      dump_dut_state();
+
+      // Set that we want to encipher and start processing.
+      $display("*** Staring encipher operation");
+      write_word(ADDR_CONFIG, (8'h00 + (AES_128_BIT_KEY << 1) + AES_ENCIPHER));
+      write_word(ADDR_CTRL, 8'h02);
+
+      // Wait a number of cycles and then switch from encipher to decipher.
+      #(10 * CLK_PERIOD);
+      $display("*** Switching to decipher operation");
+      write_word(ADDR_CONFIG, (8'h00 + (AES_128_BIT_KEY << 1) + AES_DECIPHER));
+
+      wait_ready();
+      $display("*** Ready has been set!");
+      dump_dut_state();
+      read_result();
+
+      if (result_data == expected)
+        begin
+          $display("*** TC %0d successful.", tc_number);
+          $display("");
+        end
+      else
+        begin
+          $display("*** ERROR: TC %0d NOT successful.", tc_number);
+          $display("Expected: 0x%032x", expected);
+          $display("Got:      0x%032x", result_data);
+          $display("");
+
+          error_ctr = error_ctr + 1;
+        end
+    end
+  endtask // ecb_mode_single_block_test
+
+
   //----------------------------------------------------------------
-  task nist_fips_tests;
+  // aes_test()
+  //
+  // Main test task will perform complete NIST test of AES.
+  //----------------------------------------------------------------
+  task aes_test;
     reg [255 : 0] nist_aes128_key;
     reg [255 : 0] nist_aes256_key;
 
@@ -472,8 +525,8 @@ module tb_aes();
       nist_ecb_256_enc_expected3 = 128'h23304b7a39f9f3ff067d8d8f9e24ecc7;
 
 
-      $display("NIST FIPS ECB 128 bit key tests");
-      $display("-------------------------------");
+      $display("ECB 128 bit key tests");
+      $display("---------------------");
       ecb_mode_single_block_test(8'h01, AES_ENCIPHER, nist_aes128_key, AES_128_BIT_KEY,
                                  nist_plaintext0, nist_ecb_128_enc_expected0);
 
@@ -501,8 +554,8 @@ module tb_aes();
 
 
       $display("");
-      $display("NIST FIPS ECB 256 bit key tests");
-      $display("-------------------------------");
+      $display("ECB 256 bit key tests");
+      $display("---------------------");
       ecb_mode_single_block_test(8'h10, AES_ENCIPHER, nist_aes256_key, AES_256_BIT_KEY,
                                  nist_plaintext0, nist_ecb_256_enc_expected0);
 
@@ -527,34 +580,14 @@ module tb_aes();
 
       ecb_mode_single_block_test(8'h17, AES_DECIPHER, nist_aes256_key, AES_256_BIT_KEY,
                                  nist_ecb_256_enc_expected3, nist_plaintext3);
-    end
-  endtask // aes_test
-
 
-  //----------------------------------------------------------------
-  // nist_kwp_test()
-  //
-  // Test that we can perform operations based on NIST KWP
-  // AE 128 test vectors.
-  //----------------------------------------------------------------
-  task nist_kwp_test;
-    reg [255 : 0] kwp_key;
-    reg [127 : 0] kwp_plaintext;
-    reg [127 : 0] kwp_expected;
 
-    begin
-      kwp_key       = 256'hc03db3cc1416dcd1c069a195a8d77e3d00000000000000000000000000000000;
-      kwp_plaintext = 128'ha65959a60000001f46f87f58cdda4200;
-      kwp_expected  = 128'hd1bac797ff82fa4bde9f7490729fd0a7;
-
-      $display("");
-      $display("NIST KWP AE 128 bit test");
-
-      ecb_mode_single_block_test(8'h18, AES_ENCIPHER, kwp_key, AES_128_BIT_KEY,
-                                 kwp_plaintext, kwp_expected);
+      $display("Block processing mangling test");
+      $display("------------------------------");
+      single_block_mangle_test(8'h18, nist_aes128_key, nist_plaintext0,
+                               nist_ecb_128_enc_expected0);
     end
-  endtask // nist_kwp_test
-
+  endtask // aes_test
 
 
   //----------------------------------------------------------------
@@ -573,8 +606,7 @@ module tb_aes();
       reset_dut();
       dump_dut_state();
 
-      nist_fips_tests();
-      nist_kwp_test();
+      aes_test();
 
       display_test_results();