Java SHA256 sha256Hash(File file)

Description

Calculate the SHA-256 hash for a given file efficiently.

License

Open Source License

Parameter

Parameter	Description
file	a parameter

Exception

Parameter	Description
IOException	an exception

Return

Byte array containing the hash

Declaration

public static byte[] sha256Hash(File file) throws IOException 

Method Source Code

//package com.java2s;
/*//from  ww  w. jav a 2s.c  o  m
 * --------------------------
 * |    Ring Machine 2      |
 * |                        |
 * |         /---\          |
 * |         |   |          |
 * |         \---/          |
 * |                        |
 * | The Crowdsourced CDN   |
 * --------------------------
 * 
 * Copyright (C) 2012 Eric Goodwin
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

import java.io.*;

import java.security.*;

public class Main {
    /**
     * Calculate the SHA-256 hash for a given file efficiently.
     * 
     * @param file
     * @return Byte array containing the hash
     * @throws IOException
     */
    public static byte[] sha256Hash(File file) throws IOException {
        FileInputStream in = new FileInputStream(file);
        return sha256Hash(in);
    }

    public static byte[] sha256Hash(InputStream in) throws IOException {
        MessageDigest sha256 = null;
        try {
            sha256 = MessageDigest.getInstance("SHA-256");
        } catch (NoSuchAlgorithmException e) {
            // This should not happen, ever
            return new byte[0];
        }
        DigestInputStream din = new DigestInputStream(in, sha256);
        din.on(true);
        byte[] buffer = new byte[8192];
        while (din.read(buffer) != -1)
            // Read everything into the digest input
            ;

        return sha256.digest();
    }
}

Related

1. sha256Digest(final InputStream data)
2. sha256Encode(String message)
3. sha256encrypt(String phrase)
4. sha256Hash()
5. sha256Hash(byte[] data)
6. sha256Hash(final String tohash)
7. sha256HashHex(String data)
8. SHA256Sum(final @Nonnull byte[] bytes)