Fix: missing files from last commit

Implementierung/.gitignore

@@ -1,2 +1,3 @@
 build
 md2
+testfile*

Implementierung/lib/md2_impls/md2_0.h

@@ -0,0 +1,14 @@
+#ifndef MD2_0_H
+#define MD2_0_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+void md2_hash_0(size_t len, const uint8_t buf[], uint8_t out[16]);
+void md2_checksum_0(size_t len, uint8_t* buf);
+
+#endif  // MD2_0_H

Implementierung/lib/md2_impls/md2_common.h

@@ -0,0 +1,25 @@
+#ifndef MD2_COMMON_H
+#define MD2_COMMON_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+/**
+ * @brief Some digits of pi
+ *
+ */
+extern unsigned char MD2_PI_SUBST[256];
+
+/**
+ * @brief Print a buffer for debugging
+ *
+ * @param len length
+ * @param buf buffer
+ */
+void md2_print_buf(size_t len, uint8_t buf[len]);
+
+#endif  // MD2_COMMON_H

Implementierung/src/md2_impls/md2_0.c

@@ -0,0 +1,75 @@
+#include "../../lib/md2_impls/md2_0.h"
+
+#include "../../lib/md2_impls/md2_common.h"
+
+void md2_checksum_0(size_t len, uint8_t* buf) {
+  uint8_t l = 0;
+
+  for (int i = 0; i < len / 16; i++) {
+    for (int j = 0; j < 16; j++) {
+      u_int8_t c = buf[i * 16 + j];
+      // reference is wrong. It says: Set C[j] to S[c xor L]. But it should be:
+      buf[len + j] ^= MD2_PI_SUBST[c ^ l];
+      l = buf[len + j];
+    }
+  }
+}
+
+void md2_hash_0(size_t len, const uint8_t buf[len], uint8_t out[16]) {
+  // === step 1 ===
+  int paddingNeeded = 16 - (len % 16);
+  uint8_t originalPadding = paddingNeeded;
+  len += paddingNeeded;
+
+  // printf("len: %d\n", len);
+
+  // +16 for the checksum
+  uint8_t* newBuf = calloc(len + 16, sizeof(uint8_t));
+  // TODO: null check
+  memcpy(newBuf, buf, len - paddingNeeded);
+
+  // printBuf(len + 16, newBuf);
+
+  while (paddingNeeded > 0) {
+    newBuf[len - paddingNeeded] = originalPadding;
+    paddingNeeded--;
+  }
+  // printf("buf with padding: ");
+  // printBuf(len + 16, newBuf);
+
+  // === step 2 ===
+  md2_checksum_0(len, newBuf);
+
+  // printf("buf with cecksum: ");
+  // printBuf(len + 16, newBuf);
+
+  // === step 3 ===
+  uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
+  // TODO: add null check
+
+  // === step 4 ===
+  // <= because we need to hash the last block too
+  for (int i = 0; i <= (len + 16) / 16 - 1; i++) {
+    for (int j = 0; j < 16; j++) {
+      messageDigestBuf[16 + j] = newBuf[i * 16 + j];
+      messageDigestBuf[32 + j] =
+          (messageDigestBuf[16 + j] ^ messageDigestBuf[j]);
+    }
+
+    u_int8_t t = 0;
+
+    for (int j = 0; j < 18; j++) {
+      for (int k = 0; k < 48; k++) {
+        t = messageDigestBuf[k] = messageDigestBuf[k] ^ MD2_PI_SUBST[t];
+      }
+      t = (t + j) % 256;
+    }
+  }
+  // printf("messageDigestBuf: \n");
+  // printBuf(16, messageDigestBuf);
+
+  memcpy(out, messageDigestBuf, 16);
+
+  free(messageDigestBuf);
+  free(newBuf);
+}

Implementierung/src/md2_impls/md2_common.c

@@ -0,0 +1,29 @@
+#include "../../lib/md2_impls/md2_common.h"
+
+// Source: https://datatracker.ietf.org/doc/html/rfc1319
+unsigned char MD2_PI_SUBST[256] = {
+    41,  46,  67,  201, 162, 216, 124, 1,   61,  54,  84,  161, 236, 240, 6,
+    19,  98,  167, 5,   243, 192, 199, 115, 140, 152, 147, 43,  217, 188, 76,
+    130, 202, 30,  155, 87,  60,  253, 212, 224, 22,  103, 66,  111, 24,  138,
+    23,  229, 18,  190, 78,  196, 214, 218, 158, 222, 73,  160, 251, 245, 142,
+    187, 47,  238, 122, 169, 104, 121, 145, 21,  178, 7,   63,  148, 194, 16,
+    137, 11,  34,  95,  33,  128, 127, 93,  154, 90,  144, 50,  39,  53,  62,
+    204, 231, 191, 247, 151, 3,   255, 25,  48,  179, 72,  165, 181, 209, 215,
+    94,  146, 42,  172, 86,  170, 198, 79,  184, 56,  210, 150, 164, 125, 182,
+    118, 252, 107, 226, 156, 116, 4,   241, 69,  157, 112, 89,  100, 113, 135,
+    32,  134, 91,  207, 101, 230, 45,  168, 2,   27,  96,  37,  173, 174, 176,
+    185, 246, 28,  70,  97,  105, 52,  64,  126, 15,  85,  71,  163, 35,  221,
+    81,  175, 58,  195, 92,  249, 206, 186, 197, 234, 38,  44,  83,  13,  110,
+    133, 40,  132, 9,   211, 223, 205, 244, 65,  129, 77,  82,  106, 220, 55,
+    200, 108, 193, 171, 250, 36,  225, 123, 8,   12,  189, 177, 74,  120, 136,
+    149, 139, 227, 99,  232, 109, 233, 203, 213, 254, 59,  0,   29,  57,  242,
+    239, 183, 14,  102, 88,  208, 228, 166, 119, 114, 248, 235, 117, 75,  10,
+    49,  68,  80,  180, 143, 237, 31,  26,  219, 153, 141, 51,  159, 17,  131,
+    20};
+
+void md2_print_buf(size_t len, uint8_t buf[len]) {
+  for (int i = 0; i < len; i++) {
+    printf("'%02x',", buf[i]);
+  }
+  printf("\n");
+}