des_keyschedule: implement brute-force

SideChannelMarvels · Nov 17, 2016 · bb29a53 · bb29a53
1 parent 22ac281
commit bb29a53
Showing 1 changed file with 73 additions and 25 deletions.
diff --git a/utils/des_keyschedule.c b/utils/des_keyschedule.c
@@ -6,18 +6,19 @@
 /*                                                                       */
 /* Usage:                                                                */
 /* des_keyschedule DES_key_in_hex                                        */
-/* des_keyschedule Round_key_in_hex plaintext_in_hex ciphertext_in_hex   */
+/* des_keyschedule Round1_key_in_hex plaintext_in_hex ciphertext_in_hex  */
 /*                                                                       */
 /* Examples:                                                             */
-/* des_keyschedule 11223344556677881122334455667788                      */
-/* des_keyschedule 23D7F7B876B180306793B37432F5C4FC 1                    */
-/* des_keyschedule 43EDA420DD033E7627347DC2CC6E0B4E 9                    */
-/* des_keyschedule EAC68B6B37C5B51D10F1C8DFDC9FC391 10                   */
+/* des_keyschedule 3032343234363236                                      */
+/* des_keyschedule 502CACC603C7 1122334455667788 c403d32e2bc6cfee        */
+/* des_keyschedule 14 02 32 2C 31 20 0F 07 \                             */
+/*                 1122334455667788 c403d32e2bc6cfee                     */
 /*                                                                       */
-/* Note that parity bits are always discarded                            */
+/* Note that parity bits are always ignored                              */
 /*                                                                       */
 /* Based on the unlicensed DES code https://github.com/mimoo/DES         */
-/* and released under the same licensing terms:                          */
+/* (minus the bugs)                                                      */
+/* and released under the following licensing terms:                     */
 /*                                                                       */
 /* This is free and unencumbered software released into the public domain*/
 /*                                                                       */
@@ -52,25 +53,72 @@
 
 
 int main(int argc, char **argv) {
-    uint64_t key, round_key, next_key, possible_keys[256];
-    if(argc < 2) {
-        printf("Please give a key as argument\n");
-        return 1;
+    uint64_t key, round_key, next_key, possible_keys[256], plain, cipher, scratch;
+    if((argc != 2) && (argc != 4) && (argc != 11)) {
+        printf("Usage: \n%s DES_key_in_hex\n", argv[0]);
+        printf("%s Round1_key_in_hex plaintext_in_hex ciphertext_in_hex\n", argv[0]);
+        printf("%s R1.1 R1.2 R1.3 R1.4 R1.5 R1.6 R1.7 R1.8 plaintext_in_hex ciphertext_in_hex\n", argv[0]);
+        return EXIT_FAILURE;
     }
-    key = strtoull(argv[1], NULL, 16);
-    printf("Input key: %016" PRIx64 "\n", key);
-    round_key = key;
-    key_schedule(&round_key, &next_key, 0);
-    printf("Round key: %016" PRIx64 "\n", round_key);
-    printf("Reversing round key...\n");
-    reverse_key_schedule(round_key, 0, possible_keys);
-    for(int i = 0; i < 256; i++) {
-        printf("%016" PRIx64 "\n", possible_keys[i]);
-        if((possible_keys[i] & 0x00000000fefefefefefe) == (key & 0x00000000fefefefefefe)) {
-            printf("Key found at offset %d!\n", i);
-            return 0;
+    if (argc==2) { // normal mode
+        key = strtoull(argv[1], NULL, 16);
+        printf("Input key: %016" PRIx64 "\n", key);
+        round_key = key;
+        key_schedule(&round_key, &next_key, 0);
+    } else { // reverse mode
+        if (argc==4) { // 48-bit round key
+            round_key = strtoull(argv[1], NULL, 16) << 16;
+            plain = strtoull(argv[2], NULL, 16);
+            cipher = strtoull(argv[3], NULL, 16);
+        } else { // 8 * 6-bit round key
+            round_key = 0;
+            int i;
+            for (i=0;i<8;i++) {
+                round_key <<=6;
+                round_key += strtoul(argv[i+1], NULL, 16);
+            }
+            round_key <<= 16;
+            plain = strtoull(argv[9], NULL, 16);
+            cipher = strtoull(argv[10], NULL, 16);
         }
     }
-    printf("Key not found :(\n");
-    return 1;
+    printf("Round1 key: %08X%04X == %02X %02X %02X %02X %02X %02X %02X %02X\n",
+        (uint32_t)(round_key >> 32), (uint32_t)((round_key >> 16) & 0xffff),
+        (uint8_t)((round_key >> (42+16)) & 0x3F),
+        (uint8_t)((round_key >> (36+16)) & 0x3F),
+        (uint8_t)((round_key >> (30+16)) & 0x3F),
+        (uint8_t)((round_key >> (24+16)) & 0x3F),
+        (uint8_t)((round_key >> (18+16)) & 0x3F),
+        (uint8_t)((round_key >> (12+16)) & 0x3F),
+        (uint8_t)((round_key >> ( 6+16)) & 0x3F),
+        (uint8_t)((round_key >> ( 0+16)) & 0x3F));
+    if (argc==2) { // normal mode
+        return EXIT_SUCCESS;
+    } else { // reverse mode
+        printf("Plain:  %016" PRIx64 "\n", plain);
+        printf("Cipher: %016" PRIx64 "\n", cipher);
+        printf("Reversing key scheduling...\n");
+        reverse_key_schedule(round_key, 0, possible_keys);
+        for(int i = 0; i < 256; i++) {
+            scratch = plain;
+            round_key = possible_keys[i];
+            Permutation(&scratch, 1);
+            for (int j=0;j<16;j++) {
+                key_schedule(&round_key, &next_key, j);
+                rounds(&scratch, round_key);
+                round_key = next_key;
+            }
+            scratch = (scratch >> 32) + (scratch << 32);
+            Permutation(&scratch, 0);
+//            printf("%016" PRIx64 ": %016" PRIx64 " -> %016" PRIx64 " =? %016" PRIx64 "\n",
+//                possible_keys[i], plain, scratch, cipher);
+            if(scratch == cipher) {
+                printf("Key found at offset %d: ", i);
+                printf("%016" PRIx64 "\n", possible_keys[i]);
+                return EXIT_SUCCESS;
+            }
+        }
+        printf("Key not found :(\n");
+        return EXIT_FAILURE;
+    }
 }