From 9e226414252e02eb1340fdaf75f76f00d6ded77c Mon Sep 17 00:00:00 2001
From: Mario Vavti <mario@mariovavti.com>
Date: Thu, 4 Feb 2021 22:20:55 +0100
Subject: add Lib/Keyutils

---
 Zotlabs/Lib/Keyutils.php | 99 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 Zotlabs/Lib/Keyutils.php

diff --git a/Zotlabs/Lib/Keyutils.php b/Zotlabs/Lib/Keyutils.php
new file mode 100644
index 000000000..d4b660c04
--- /dev/null
+++ b/Zotlabs/Lib/Keyutils.php
@@ -0,0 +1,99 @@
+<?php
+
+namespace Zotlabs\Lib;
+
+use phpseclib\Crypt\RSA;
+use phpseclib\Math\BigInteger;
+
+/**
+ * Keyutils
+ * Convert RSA keys between various formats
+ */
+class Keyutils {
+
+	/**
+	 * @param string $m modulo
+	 * @param string $e exponent
+	 * @return string
+	 */
+	public static function meToPem($m, $e) {
+
+		$rsa = new RSA();
+		$rsa->loadKey([
+			'e' => new BigInteger($e, 256),
+			'n' => new BigInteger($m, 256)
+		]);
+		return $rsa->getPublicKey();
+
+	}
+
+	/**
+	 * @param string key
+	 * @return string
+	 */
+	public static function rsaToPem($key) {
+
+		$rsa = new RSA();
+		$rsa->setPublicKey($key);
+
+		return $rsa->getPublicKey(RSA::PUBLIC_FORMAT_PKCS8);
+
+	}
+
+	/**
+	 * @param string key
+	 * @return string
+	 */
+	public static function pemToRsa($key) {
+
+		$rsa = new RSA();
+		$rsa->setPublicKey($key);
+
+		return $rsa->getPublicKey(RSA::PUBLIC_FORMAT_PKCS1);
+
+	}
+
+	/**
+	 * @param string $key key
+	 * @param string $m reference modulo
+	 * @param string $e reference exponent
+	 */
+	public static function pemToMe($key, &$m, &$e) {
+
+		$rsa = new RSA();
+		$rsa->loadKey($key);
+		$rsa->setPublicKey();
+
+		$e = $rsa->modulus->toBytes();
+		$m = $rsa->exponent->toBytes();
+
+	}
+
+	/**
+	 * @param string $pubkey
+	 * @return string
+	 */
+	public static function salmonKey($pubkey) {
+		self::pemToMe($pubkey, $m, $e);
+		return 'RSA' . '.' . base64url_encode($m, true) . '.' . base64url_encode($e, true);
+	}
+
+	/**
+	 * @param string $key
+	 * @return string
+	 */
+	public static function convertSalmonKey($key) {
+		if (strstr($key, ','))
+			$rawkey = substr($key, strpos($key, ',') + 1);
+		else
+			$rawkey = substr($key, 5);
+
+		$key_info = explode('.', $rawkey);
+
+		$m = base64url_decode($key_info[1]);
+		$e = base64url_decode($key_info[2]);
+
+		return self::meToPem($m, $e);
+	}
+
+}
\ No newline at end of file
-- 
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