Added initial crypto library
This commit is contained in:
Isaac Parenteau
189
src/main/java/net/locusworks/crypto/HashSalt.java
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189
src/main/java/net/locusworks/crypto/HashSalt.java
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package net.locusworks.crypto;
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import java.math.BigInteger;
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import java.security.NoSuchAlgorithmException;
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import java.security.SecureRandom;
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import java.security.spec.InvalidKeySpecException;
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import javax.crypto.SecretKeyFactory;
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import javax.crypto.spec.PBEKeySpec;
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/**
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* The type Hash salt.
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* @author Isaac Parenteau
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* @version 1.0.0
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* @date 02/15/2018
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*/
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public class HashSalt {
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/**
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* The constant PBKDF2_ALGORITHM.
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*/
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private static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA256";
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/**
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* The constant SALT_BYTE_SIZE.
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*/
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private static final int SALT_BYTE_SIZE = 24;
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/**
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* The constant HASH_BYTE_SIZE.
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*/
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private static final int HASH_BYTE_SIZE = 24;
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/**
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* The constant PBKDF2_ITERATIONS.
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*/
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private static final int PBKDF2_ITERATIONS = 1000;
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/**
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* The constant ITERATION_INDEX.
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*/
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private static final int ITERATION_INDEX = 0;
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/**
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* The constant SALT_INDEX.
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*/
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private static final int SALT_INDEX = 1;
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/**
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* The constant PBKDF2_INDEX.
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*/
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private static final int PBKDF2_INDEX = 2;
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/**
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* Returns a salted PBKDF2 hash of the password.
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*
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* @param password the password to hash
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*
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* @return a salted PBKDF2 hash of the password
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* @throws NoSuchAlgorithmException the no such algorithm exception
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* @throws InvalidKeySpecException the invalid key spec exception
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*/
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public static String createHash(String password) throws NoSuchAlgorithmException, InvalidKeySpecException {
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return createHash(password.toCharArray());
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}
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/**
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* Returns a salted PBKDF2 hash of the password.
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*
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* @param password the password to hash
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*
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* @return a salted PBKDF2 hash of the password
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* @throws NoSuchAlgorithmException the no such algorithm exception
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* @throws InvalidKeySpecException the invalid key spec exception
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*/
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public static String createHash(char[] password) throws NoSuchAlgorithmException, InvalidKeySpecException {
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// Generate a random salt
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SecureRandom random = new SecureRandom();
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byte[] salt = new byte[SALT_BYTE_SIZE];
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random.nextBytes(salt);
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// Hash the password
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byte[] hash = pbkdf2(password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE);
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// format iterations:salt:hash
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return PBKDF2_ITERATIONS + ":" + toHex(salt) + ":" + toHex(hash);
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}
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/**
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* Validates a password using a hash.
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*
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* @param password the password to check
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* @param correctHash the hash of the valid password
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*
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* @return true if the password is correct, false if not
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* @throws NoSuchAlgorithmException the no such algorithm exception
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* @throws InvalidKeySpecException the invalid key spec exception
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*/
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public static boolean validatePassword(String password, String correctHash) throws NoSuchAlgorithmException, InvalidKeySpecException {
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return validatePassword(password.toCharArray(), correctHash);
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}
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/**
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* Validates a password using a hash.
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*
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* @param password the password to check
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* @param correctHash the hash of the valid password
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*
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* @return true if the password is correct, false if not
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* @throws NoSuchAlgorithmException the no such algorithm exception
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* @throws InvalidKeySpecException the invalid key spec exception
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*/
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public static boolean validatePassword(char[] password, String correctHash) throws NoSuchAlgorithmException, InvalidKeySpecException {
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// Decode the hash into its parameters
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String[] params = correctHash.split(":");
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int iterations = Integer.parseInt(params[ITERATION_INDEX]);
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byte[] salt = fromHex(params[SALT_INDEX]);
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byte[] hash = fromHex(params[PBKDF2_INDEX]);
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// Compute the hash of the provided password, using the same salt,
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// iteration count, and hash length
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byte[] testHash = pbkdf2(password, salt, iterations, hash.length);
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// Compare the hashes in constant time. The password is correct if
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// both hashes match.
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return slowEquals(hash, testHash);
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}
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/**
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* Compares two byte arrays in length-constant time. This comparison method
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* is used so that password hashes cannot be extracted from an on-line
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* system using a timing attack and then attacked off-line.
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*
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* @param a the first byte array
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* @param b the second byte array
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* @return true if both byte arrays are the same, false if not
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*/
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private static boolean slowEquals(byte[] a, byte[] b) {
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int diff = a.length ^ b.length;
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for(int i = 0; i < a.length && i < b.length; i++)
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diff |= a[i] ^ b[i];
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return diff == 0;
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}
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/**
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* Computes the PBKDF2 hash of a password.
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*
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* @param password the password to hash.
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* @param salt the salt
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* @param iterations the iteration count (slowness factor)
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* @param bytes the length of the hash to compute in bytes
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* @return the PBDKF2 hash of the password
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*/
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private static byte[] pbkdf2(char[] password, byte[] salt, int iterations, int bytes) throws NoSuchAlgorithmException, InvalidKeySpecException {
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PBEKeySpec spec = new PBEKeySpec(password, salt, iterations, bytes * 8);
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SecretKeyFactory skf = SecretKeyFactory.getInstance(PBKDF2_ALGORITHM);
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return skf.generateSecret(spec).getEncoded();
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}
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/**
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* Converts a string of hexadecimal characters into a byte array.
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*
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* @param hex the hex string
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* @return the hex string decoded into a byte array
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*/
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private static byte[] fromHex(String hex) {
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byte[] binary = new byte[hex.length() / 2];
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for(int i = 0; i < binary.length; i++) {
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binary[i] = (byte)Integer.parseInt(hex.substring(2*i, 2*i+2), 16);
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}
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return binary;
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}
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/**
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* Converts a byte array into a hexadecimal string.
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*
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* @param array the byte array to convert
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* @return a length*2 character string encoding the byte array
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*/
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private static String toHex(byte[] array) {
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BigInteger bi = new BigInteger(1, array);
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String hex = bi.toString(16);
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int paddingLength = (array.length * 2) - hex.length();
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if(paddingLength > 0)
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return String.format("%0" + paddingLength + "d", 0) + hex;
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else
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return hex;
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}
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public static void main (String[] args) throws Exception {
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if (args == null || !(args.length > 0)) {
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throw new IllegalArgumentException("No args provided. Need password as argument");
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}
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System.out.println(HashSalt.createHash(String.valueOf(args[0])));
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}
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}
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