How to use

MessageDigest

in

java.security

public static String checkSum(String path) {
  String checksum = null;
  try {
    FileInputStream fis = new FileInputStream(path);
    MessageDigest md = MessageDigest.getInstance("MD5");
    //Using MessageDigest update() method to provide input
    byte[] buffer = new byte[8192];
    int numOfBytesRead;
    while ((numOfBytesRead = fis.read(buffer)) > 0) {
      md.update(buffer, 0, numOfBytesRead);
    }
    byte[] hash = md.digest();
    checksum = new BigInteger(1, hash).toString(16); //don't use this, truncates leading zero
  } catch (IOException | NoSuchAlgorithmException ignored) {
  }
  assert checksum != null;
  return checksum.trim();
}

 String plaintext = "your text here";
MessageDigest m = MessageDigest.getInstance("MD5");
m.reset();
m.update(plaintext.getBytes());
byte[] digest = m.digest();
BigInteger bigInt = new BigInteger(1,digest);
String hashtext = bigInt.toString(16);
// Now we need to zero pad it if you actually want the full 32 chars.
while(hashtext.length() < 32 ){
 hashtext = "0"+hashtext;
}

 import java.security.*;

..

byte[] bytesOfMessage = yourString.getBytes("UTF-8");

MessageDigest md = MessageDigest.getInstance("MD5");
byte[] thedigest = md.digest(bytesOfMessage);

private byte[] md5(String value) {
  MessageDigest md5;
  try {
    md5 = MessageDigest.getInstance("MD5");
  } catch (NoSuchAlgorithmException e) {
    throw new IllegalStateException(e.getMessage(), e);
  }
  md5.reset();
  byte[] bytes = value.getBytes(StandardCharsets.UTF_8);
  md5.update(bytes);
  return md5.digest();
}

 MessageDigest md = MessageDigest.getInstance("MD5");
try (InputStream is = Files.newInputStream(Paths.get("file.txt"));
   DigestInputStream dis = new DigestInputStream(is, md)) 
{
 /* Read decorated stream (dis) to EOF as normal... */
}
byte[] digest = md.digest();

MessageDigest digest;
try {
  digest = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
  Log.e(TAG, "Exception while getting digest", e);
  is = new FileInputStream(updateFile);
} catch (FileNotFoundException e) {
  Log.e(TAG, "Exception while getting FileInputStream", e);
int read;
try {
  while ((read = is.read(buffer)) > 0) {
    digest.update(buffer, 0, read);
  byte[] md5sum = digest.digest();
  BigInteger bigInt = new BigInteger(1, md5sum);
  String output = bigInt.toString(16);
} finally {
  try {
    is.close();
  } catch (IOException e) {
    Log.e(TAG, "Exception on closing MD5 input stream", e);

InputStream in = new FileInputStream( file );
KeyStore ks = KeyStore.getInstance( KeyStore.getDefaultType() );
ks.load( in, passphrase );
in.close();
MessageDigest sha1 = MessageDigest.getInstance( "SHA1" );
MessageDigest md5 = MessageDigest.getInstance( "MD5" );
for ( int i = 0; i < chain.length; i++ ) {
  X509Certificate cert = chain[i];
  LOG.debug( " " + ( i + 1 ) + " Subject " + cert.getSubjectDN() );
  LOG.debug( "   Issuer  " + cert.getIssuerDN() );
  sha1.update( cert.getEncoded() );
  LOG.debug( "   sha1    " + toHexString( sha1.digest() ) );
  md5.update( cert.getEncoded() );
  LOG.debug( "   md5     " + toHexString( md5.digest() ) );
OutputStream out = new FileOutputStream( "jssecacerts" );
ks.store( out, passphrase );
out.close();

out.write('i');
out.write(Long.toString(value).getBytes("US-ASCII"));
out.write('e');
MessageDigest sha1;
try {
  sha1 = MessageDigest.getInstance("SHA");
} catch (NoSuchAlgorithmException e) {
  throw new Error("SHA1 not supported");
InputStream in = new FileInputStream(file);
ByteArrayOutputStream pieces = new ByteArrayOutputStream();
byte[] bytes = new byte[pieceLength];
int pieceByteCount  = 0, readCount = in.read(bytes, 0, pieceLength);
while (readCount != -1) {
  pieceByteCount += readCount;
  sha1.update(bytes, 0, readCount);
  if (pieceByteCount == pieceLength) {
    pieceByteCount = 0;
    pieces.write(sha1.digest());
  readCount = in.read(bytes, 0, pieceLength-pieceByteCount);
in.close();
if (pieceByteCount > 0)
  pieces.write(sha1.digest());
return pieces.toByteArray();

mNotificationManager.notify(NOTIFICATION_ID,mBuilder.build());
md5 = (mCurrentTask.md5!=null  ? MessageDigest.getInstance("MD5") : null);
sha1= (mCurrentTask.sha1!=null ? MessageDigest.getInstance("SHA-1") : null);
buffer = new byte[4096];
file = new File(mCurrentTask.path);
writer = new FileOutputStream(file);
reader = connection.getInputStream();
while( mRunning && (read = reader.read(buffer)) != -1 ) {
 writer.write(buffer, 0, read);
 if(md5!=null)
  md5.update(buffer, 0, read);
 if(sha1!=null)
  sha1.update(buffer, 0, read);
 if (md5 != null && !mCurrentTask.md5.equals(digest2string(md5.digest()))) {
  throw new KeyException("wrong MD5");
 } else if (sha1 != null && !mCurrentTask.sha1.equals(digest2string(sha1.digest()))) {
  throw new KeyException("wrong SHA-1");

boolean rv = false;
try {
  in = new BufferedInputStream(new FileInputStream(_file));
  in.mark(10);
  in.reset();
  MessageDigest md = _sigType.getDigestInstance();
  DigestInputStream din = new DigestInputStream(in, md);
  in = din;
  if (!_headerVerified)
      throw new EOFException();
    if (migrateTo != null)  // else verify only
      out.write(buf, 0, read);
    tot += read;
    byte[] sha = md.digest();
    din.on(false);
    Signature signature = new Signature(_sigType);
    signature.readBytes(in);
      out.flush();
      out.getFD().sync();
    } catch (IOException ioe) {}
    try { out.close(); } catch (IOException ioe) {}

tmpArchive.deleteOnExit();
MessageDigest digest = MessageDigest.getInstance("SHA-256");
try (InputStream is = component.getSource().openStream();
  FileOutputStream os = new FileOutputStream(tmpArchive)) {
 while ((bytesRead = is.read(dataBuffer, 0, 1024)) != -1) {
  digest.update(dataBuffer, 0, bytesRead);
  os.write(dataBuffer, 0, bytesRead);
String checksum = byteArrayToHex(digest.digest());
  new TarArchiveInputStream(new GzipCompressorInputStream(new FileInputStream(tmpArchive)))) {
   try (OutputStream outputFileStream = new FileOutputStream(dest)) {
    IOUtils.copy(stream, outputFileStream);

boolean ok = false;
try {
  in = new BufferedInputStream(new FileInputStream(content));
  MessageDigest md = sigType.getDigestInstance();
  out = new DigestOutputStream(new BufferedOutputStream(new FileOutputStream(_file)), md);
  out.write(MAGIC_BYTES);
  out.write((byte) 0);
  long tot = 0;
  while (tot < contentLength) {
    int read = in.read(buf, 0, (int) Math.min(buf.length, contentLength - tot));
    if (read < 0)
      throw new EOFException();
  byte[] sha = md.digest();
  out.on(false);
  SimpleDataStructure hash = sigType.getHashInstance();
  throw ioe;
} finally {
  if (in != null) try { in.close(); } catch (IOException ioe) {}
  if (out != null) try { out.close(); } catch (IOException ioe) {}
  if (!ok)

private void updateSignature(@Nonnull DexDataStore dataStore) throws IOException {
  MessageDigest md;
  try {
    md = MessageDigest.getInstance("SHA-1");
  } catch (NoSuchAlgorithmException ex) {
    throw new RuntimeException(ex);
  }
  byte[] buffer = new byte[4 * 1024];
  InputStream input = dataStore.readAt(HeaderItem.SIGNATURE_DATA_START_OFFSET);
  int bytesRead = input.read(buffer);
  while (bytesRead >= 0) {
    md.update(buffer, 0, bytesRead);
    bytesRead = input.read(buffer);
  }
  byte[] signature = md.digest();
  if (signature.length != HeaderItem.SIGNATURE_SIZE) {
    throw new RuntimeException("unexpected digest write: " + signature.length + " bytes");
  }
  // write signature
  OutputStream output = dataStore.outputAt(HeaderItem.SIGNATURE_OFFSET);
  output.write(signature);
  output.close();
}

if (getChecksum) {
 digester = MD5Hash.getDigester();
 stream = new DigestInputStream(stream, digester);
       + " with file downloaded from " + url);
    FileOutputStream fos = new FileOutputStream(f);
    outputStreams.add(fos);
    streamPathMap.put(fos, f);
  num = stream.read(buf);
  if (num > 0) {
   received += num;
   for (FileOutputStream fos : outputStreams) {
    fos.write(buf, 0, num);
     xferSec, xferKb / xferSec));
} finally {
 stream.close();
 for (FileOutputStream fos : outputStreams) {
  long flushStartTime = Time.monotonicNow();
  fos.getChannel().force(true);
  fos.close();
  double writeSec = Math.max(((float)
 MD5Hash computedDigest = new MD5Hash(digester.digest());

public static String getDigestOf(@Nonnull InputStream source) throws IOException {
  try {
    MessageDigest md5 = MessageDigest.getInstance("MD5");
    DigestInputStream in = new DigestInputStream(source, md5);
    return toHexString(md5.digest());
  } catch (NoSuchAlgorithmException e) {
    throw new IOException("MD5 not installed",e);    // impossible
  } finally {
    source.close();

try {
  for (Map.Entry<File, Object> e : includeFileMap.entrySet()) {
    messageDigest.reset();
    File src = e.getKey();
    if (!isCondition) {
    DigestInputStream dis = new DigestInputStream(fis,
                           messageDigest);
    while (dis.read(buf, 0, readBufferSize) != -1) {
    dis.close();
    fis.close();
    fis = null;
    byte[] fileDigest = messageDigest.digest();
    if (totalproperty != null) {
      allDigests.put(src, fileDigest);
    messageDigest.reset();
    for (File src : keyArray) {
      messageDigest.update(digest);
      messageDigest.update(fileName.getBytes());
    String totalChecksum = createDigestString(messageDigest.digest());
    getProject().setNewProperty(totalproperty, totalChecksum);

protected String storeAndDigest(InputStream in, OutputStream out) throws IOException {
  MessageDigest digest;
  try {
    digest = MessageDigest.getInstance(getDigestAlgorithm());
  } catch (NoSuchAlgorithmException e) {
    throw (IOException) new IOException().initCause(e);
  }
  int size = in.available();
  if (size == 0) {
    size = MAX_BUF_SIZE;
  } else if (size < MIN_BUF_SIZE) {
    size = MIN_BUF_SIZE;
  } else if (size > MAX_BUF_SIZE) {
    size = MAX_BUF_SIZE;
  }
  byte[] buf = new byte[size];
  /*
   * Copy and digest.
   */
  int n;
  while ((n = in.read(buf)) != -1) {
    digest.update(buf, 0, n);
    out.write(buf, 0, n);
  }
  out.flush();
  return toHexString(digest.digest());
}

@Override
public int read() throws IOException {
  if (this.bytesReceived == this.bytesToReceive) {
    return -1;
  }
  final int read = this.wrappedInputStream.read();
  if (read < 0) {
    throwEOFException();
  }
  ++this.bytesReceived;
  if (this.md != null) {
    this.md.update((byte) read);
    if (this.bytesReceived == this.bytesToReceive) {
      final byte[] computedKey = this.md.digest();
      if (!Arrays.equals(computedKey, this.blobKey.getHash())) {
        this.wrappedOutputStream.write(RETURN_ERROR);
        throw new IOException("Detected data corruption during transfer");
      }
      this.wrappedOutputStream.write(RETURN_OKAY);
    }
  }
  return read;
}

    return fileStream.read();
}; FileOutputStream os = new FileOutputStream(fileAbsName)) {
  int remainBytes = fileSize = proxyStream.available();
  byte[] buff = new byte[remainBytes > 1024 * 10 ? 1024 * 10 : remainBytes];
  int bytes;
  logger.info("开始写出文件:{}到:{}, size: {} bytes", fileName, fileAbsName, fileSize);
  while (remainBytes > 0) {
    bytes = proxyStream.read(buff, 0, remainBytes > buff.length ? buff.length : remainBytes);
    os.write(buff, 0, bytes);
    remainBytes -= bytes;
    logger.info("写出文件:{}:{},剩余数据量: {} bytes", fileName, fileAbsName, remainBytes);
String md5 = Hex.encodeHexString(digest.digest());

  hash = new BASE64Encoder().encode(MessageDigest.getInstance("SHA-1").digest((keys.get("Sec-WebSocket-Key") + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").getBytes()));
} catch (NoSuchAlgorithmException ex) {
  ex.printStackTrace();
socket.getInputStream().read(b);
return b;
baos.write(SINGLE_FRAME_UNMASKED);
baos.write(msg.length);
baos.write(msg);
baos.flush();
baos.close();
convertAndPrint(baos.toByteArray());