package com.simple.utils; import java.security.MessageDigest; /** * @author Stormeye * @since 2018.08.09 */ public class HashUtil { private static final java.security.SecureRandom random = new java.security.SecureRandom(); private static final char[] HEX_DIGITS = "0123456789abcdef".toCharArray(); private static final char[] CHAR_ARRAY = "_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" .toCharArray(); public static String md5(String srcStr) { return hash("MD5", srcStr); } public static String sha1(String srcStr) { return hash("SHA-1", srcStr); } public static String sha256(String srcStr) { return hash("SHA-256", srcStr); } public static String sha384(String srcStr) { return hash("SHA-384", srcStr); } public static String sha512(String srcStr) { return hash("SHA-512", srcStr); } public static String hash(String algorithm, String srcStr) { try { MessageDigest md = MessageDigest.getInstance(algorithm); byte[] bytes = md.digest(srcStr.getBytes("utf-8")); return toHex(bytes); } catch (Exception e) { throw new RuntimeException(e); } } private static String toHex(byte[] bytes) { StringBuilder ret = new StringBuilder(bytes.length * 2); for (int i = 0; i < bytes.length; i++) { ret.append(HEX_DIGITS[(bytes[i] >> 4) & 0x0f]); ret.append(HEX_DIGITS[bytes[i] & 0x0f]); } return ret.toString(); } /** * md5 128bit 16bytes sha1 160bit 20bytes sha256 256bit 32bytes sha384 * 384bit 48bytes sha512 512bit 64bytes */ public static String generateSalt(int saltLength) { StringBuilder salt = new StringBuilder(); for (int i = 0; i < saltLength; i++) { salt.append(CHAR_ARRAY[random.nextInt(CHAR_ARRAY.length)]); } return salt.toString(); } public static String generateSaltForSha256() { return generateSalt(32); } public static String generateSaltForSha512() { return generateSalt(64); } public static boolean slowEquals(byte[] a, byte[] b) { if (a == null || b == null) { return false; } int diff = a.length ^ b.length; for (int i = 0; i < a.length && i < b.length; i++) { diff |= a[i] ^ b[i]; } return diff == 0; } }