CoreLibs add Security\SymmetricEncryption

src/Security/SymmetricEncryption.php

@@ -0,0 +1,96 @@
+<?php
+
+/**
+ * very simple symmetric encryption
+ * Better use: https://paragonie.com/project/halite
+ *
+ * current code is just to encrypt and decrypt
+ *
+ * must use a valid encryption key created with
+ * Secruty\CreateKey class
+ */
+
+declare(strict_types=1);
+
+namespace CoreLibs\Security;
+
+use CoreLibs\Security\CreateKey;
+use SodiumException;
+
+class SymmetricEncryption
+{
+	/**
+	 * Encrypt a message
+	 *
+	 * @param  string $message Message to encrypt
+	 * @param  string $key     Encryption key (as hex string)
+	 * @return string
+	 * @throws \RangeException
+	 */
+	public static function encrypt(string $message, string $key): string
+	{
+		try {
+			$key = CreateKey::hex2bin($key);
+		} catch (SodiumException $e) {
+			throw new \Exception('Invalid hex key');
+		}
+		if (mb_strlen($key, '8bit') !== SODIUM_CRYPTO_SECRETBOX_KEYBYTES) {
+			throw new \RangeException(
+				'Key is not the correct size (must be '
+					. 'SODIUM_CRYPTO_SECRETBOX_KEYBYTES bytes long).'
+			);
+		}
+		$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
+
+		$cipher = base64_encode(
+			$nonce
+			. sodium_crypto_secretbox(
+				$message,
+				$nonce,
+				$key
+			)
+		);
+		sodium_memzero($message);
+		sodium_memzero($key);
+		return $cipher;
+	}
+
+	/**
+	 * Decrypt a message
+	 *
+	 * @param  string $encrypted Message encrypted with safeEncrypt()
+	 * @param  string $key       Encryption key (as hex string)
+	 * @return string
+	 * @throws \Exception
+	 */
+	public static function decrypt(string $encrypted, string $key): string
+	{
+		try {
+			$key = CreateKey::hex2bin($key);
+		} catch (SodiumException $e) {
+			throw new \Exception('Invalid hex key');
+		}
+		$decoded = base64_decode($encrypted);
+		$nonce = mb_substr($decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, '8bit');
+		$ciphertext = mb_substr($decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, null, '8bit');
+
+		$plain = false;
+		try {
+			$plain = sodium_crypto_secretbox_open(
+				$ciphertext,
+				$nonce,
+				$key
+			);
+		} catch (SodiumException $e) {
+			throw new \Exception('Invalid ciphertext (too short)');
+		}
+		if (!is_string($plain)) {
+			throw new \Exception('Invalid Key');
+		}
+		sodium_memzero($ciphertext);
+		sodium_memzero($key);
+		return $plain;
+	}
+}
+
+// __END__