openssl和Windows crypt32 AES加解密互通

// 在使用openssl加密时，为了让Windows crypt32
// API能很方便的解密，需要同步CryptDeriveKey的功能。
// 适用于win api端CryptCreateHash指定为CALG_MD5的情况。
//  https://learn.microsoft.com/zh-cn/windows/win32/api/wincrypt/nf-wincrypt-cryptderivekey?redirectedfrom=MSDN
unsigned char *crypt32DerivedKey(unsigned char *md5hash, int k /*hash长度*/,
                                 int keyBitSize) {
  /**step 1*/
  unsigned char buffer1[64];

  for (int i = 0; i < 64; i++) {
    buffer1[i] = 0x36;
  }

  // int k = n;

  for (int i = 0; i < k; i++) {
    buffer1[i] = buffer1[i] ^ md5hash[i];
  }

  /*step 2*/
  unsigned char buffer2[64];

  for (int i = 0; i < 64; i++) {
    buffer2[i] = 0x5C;
  }

  for (int i = 0; i < k; i++) {
    buffer2[i] = buffer2[i] ^ md5hash[i];
  }
  /*step 3*/
  unsigned char hash1[MD5_DIGEST_LENGTH];
  MD5(buffer1, 64, hash1);
  /*step 4*/
  unsigned char hash2[MD5_DIGEST_LENGTH];
  MD5(buffer2, 64, hash2);
  /*step 5*/
  int resultLen = keyBitSize / 8;
  unsigned char *outputkey = (unsigned char *)malloc(resultLen);
  for (int i = 0; i < resultLen; i++) {
    if (i < 16)
      outputkey[i] = hash1[i];
    else
      outputkey[i] = hash2[i - 16];
  }

  return outputkey;
}