code: public static byte[] hash(InputStream in) throws IOException {
          if (HASH_DIGEST == null) {
              throw new EvernoteUtilException(EDAM_HASH_ALGORITHM + " not supported", new NoSuchAlgorithmException(EDAM_HASH_ALGORITHM));
          }
  
          byte[] buf = new byte[1024];
          int n;
          while ((n = in.read(buf)) != -1) {
              HASH_DIGEST.update(buf, 0, n);
          }
          return HASH_DIGEST.digest();
      }
docs: Returns an MD5 checksum of the contents of the provided InputStream.