From 091c6af2a0f232600981b10214b925706a859a37 Mon Sep 17 00:00:00 2001
From: Niki Roo <niki@nikiroo.be>
Date: Mon, 11 May 2020 18:28:05 +0200
Subject: [PATCH] Hash/Cookie utils

---
 CookieUtils.java | 57 +++++++++++++++++++++++++++++++
 HashUtils.java   | 89 ++++++++++++++++++++++++++++++++++++++++++++++++
 StringUtils.java |  3 ++
 3 files changed, 149 insertions(+)
 create mode 100644 CookieUtils.java
 create mode 100644 HashUtils.java

diff --git a/CookieUtils.java b/CookieUtils.java
new file mode 100644
index 0000000..f082026
--- /dev/null
+++ b/CookieUtils.java
@@ -0,0 +1,57 @@
+package be.nikiroo.utils;
+
+import java.util.Date;
+
+public class CookieUtils {
+	/**
+	 * The number of seconds for the period (we accept the current or the
+	 * previous period as valid for a cookie, via "offset").
+	 */
+	static public int GRACE_PERIOD = 3600 * 1000; // between 1 and 2h
+
+	/**
+	 * Generate a new cookie value from the user (email) and an offset.
+	 * <p>
+	 * You should use an offset of "0" when creating the cookie, and an offset
+	 * of "0" or "-1" if required when checking for the value (the idea is to
+	 * allow a cookie to persist across two timespans; if not, the cookie will
+	 * be expired the very second we switch to a new timespan).
+	 * 
+	 * @param value
+	 *            the value to generate a cookie for -- you must be able to
+	 *            regenerate it in order to check it later
+	 * @param offset
+	 *            the offset (should be 0 for creating, 0 then -1 if needed for
+	 *            checking)
+	 * 
+	 * @return the new cookie
+	 */
+	static public String generateCookie(String value, int offset) {
+		long unixTime = (long) Math.floor(new Date().getTime() / GRACE_PERIOD)
+				+ offset;
+		return HashUtils.sha512(value + Long.toString(unixTime));
+	}
+
+	/**
+	 * Check the given cookie.
+	 * 
+	 * @param value
+	 *            the value to generate a cookie for -- you must be able to
+	 *            regenerate it in order to check it later
+	 * @param cookie
+	 *            the cookie to validate
+	 * 
+	 * @return TRUE if it is correct
+	 */
+	static public boolean validateCookie(String value, String cookie) {
+		if (cookie != null)
+			cookie = cookie.trim();
+
+		String newCookie = generateCookie(value, 0);
+		if (!newCookie.equals(cookie)) {
+			newCookie = generateCookie(value, -1);
+		}
+
+		return newCookie.equals(cookie);
+	}
+}
diff --git a/HashUtils.java b/HashUtils.java
new file mode 100644
index 0000000..df8d7c6
--- /dev/null
+++ b/HashUtils.java
@@ -0,0 +1,89 @@
+package be.nikiroo.utils;
+
+import java.io.UnsupportedEncodingException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+/**
+ * Small class to easily hash some values in a few different ways.
+ * <p>
+ * Does <b>not</b> handle the salt itself, you have to add it yourself.
+ * 
+ * @author niki
+ */
+public class HashUtils {
+	/**
+	 * Hash the given value.
+	 * 
+	 * @param value
+	 *            the value to hash
+	 * 
+	 * @return the hash that can be used to confirm a value
+	 * 
+	 * @throws RuntimeException
+	 *             if UTF-8 support is not available (!) or SHA-512 support is
+	 *             not available
+	 * @throws NullPointerException
+	 *             if email or pass is NULL
+	 */
+	static public String sha512(String value) {
+		return hash("SHA-512", value);
+	}
+
+	/**
+	 * Hash the given value.
+	 * 
+	 * @param value
+	 *            the value to hash
+	 * 
+	 * @return the hash that can be used to confirm the a value
+	 * 
+	 * @throws RuntimeException
+	 *             if UTF-8 support is not available (!) or MD5 support is not
+	 *             available
+	 * @throws NullPointerException
+	 *             if email or pass is NULL
+	 */
+	static public String md5(String value) {
+		return hash("MD5", value);
+	}
+
+	/**
+	 * Hash the given value.
+	 * 
+	 * @param algo
+	 *            the hash algorithm to use ("MD5" and "SHA-512" are supported)
+	 * @param value
+	 *            the value to hash
+	 * 
+	 * @return the hash that can be used to confirm a value
+	 * 
+	 * @throws RuntimeException
+	 *             if UTF-8 support is not available (!) or the algorithm
+	 *             support is not available
+	 * @throws NullPointerException
+	 *             if email or pass is NULL
+	 */
+	static private String hash(String algo, String value) {
+		try {
+			MessageDigest md = MessageDigest.getInstance(algo);
+			md.update(value.getBytes("UTF-8"));
+			byte byteData[] = md.digest();
+
+			StringBuffer hexString = new StringBuffer();
+			for (int i = 0; i < byteData.length; i++) {
+				String hex = Integer.toHexString(0xff & byteData[i]);
+				if (hex.length() % 2 == 1)
+					hexString.append('0');
+				hexString.append(hex);
+			}
+
+			return hexString.toString();
+		} catch (NoSuchAlgorithmException e) {
+			throw new RuntimeException(algo + " hashing not available", e);
+		} catch (UnsupportedEncodingException e) {
+			throw new RuntimeException(
+					"UTF-8 encoding is required in a compatible JVM", e);
+		}
+	}
+}
diff --git a/StringUtils.java b/StringUtils.java
index b3c1071..be1c654 100644
--- a/StringUtils.java
+++ b/StringUtils.java
@@ -454,7 +454,10 @@ public class StringUtils {
 	 *            the input data
 	 * 
 	 * @return the hash
+	 * 
+	 * @deprecated please use {@link HashUtils}
 	 */
+	@Deprecated
 	static public String getMd5Hash(String input) {
 		try {
 			MessageDigest md = MessageDigest.getInstance("MD5");
-- 
2.27.0