1 files changed, 74 insertions, 0 deletions
diff --git a/library/sodium-plus/lib/polyfill.js b/library/sodium-plus/lib/polyfill.js
new file mode 100644
index 000000000..faf6d75e5
--- /dev/null
+++ b/library/sodium-plus/lib/polyfill.js
@@ -0,0 +1,74 @@
+"use strict";
+const crypto = require('crypto');
+const Poly1305 = require('poly1305-js');
+const Util = require('./util');
+const XSalsa20 = require('xsalsa20');
+
+/* istanbul ignore if */
+if (typeof (Buffer) === 'undefined') {
+    let Buffer = require('buffer/').Buffer;
+}
+
+module.exports = class SodiumPolyfill {
+
+    /**
+     * @param {string|Buffer} message
+     * @param {CryptographyKey} key
+     * @return {Promise<Buffer>}
+     */
+    static async crypto_onetimeauth(message, key) {
+        return Poly1305.onetimeauth(
+            await Util.toBuffer(message),
+            key.getBuffer()
+        );
+    }
+
+    /**
+     * @param {string|Buffer} message
+     * @param {CryptographyKey} key
+     * @param {Buffer} tag
+     * @return {Promise<boolean>}
+     */
+    static async crypto_onetimeauth_verify(message, key, tag) {
+        return Poly1305.onetimeauth_verify(
+            await Util.toBuffer(message),
+            key.getBuffer(),
+            await Util.toBuffer(tag)
+        );
+    }
+
+    /**
+     * @param {string|Buffer} plaintext
+     * @param {Buffer} nonce
+     * @param {CryptographyKey} key
+     * @return {Promise<Buffer>}
+     */
+    static async crypto_stream_xor(plaintext, nonce, key) {
+        const stream = XSalsa20(nonce, key.getBuffer());
+        const output = stream.update(plaintext);
+        stream.finalize();
+        return Util.toBuffer(output);
+    }
+
+    /**
+     * Polyfill crypto_pwhash_str_needs_rehash() for bindings that don't
+     * include this (somewhat new) helper function.
+     *
+     * @param {string|Buffer} hash
+     * @param {number} opslimit
+     * @param {number} memlimit
+     * @return {Promise<boolean>}
+     */
+    static async crypto_pwhash_str_needs_rehash(hash, opslimit, memlimit) {
+        const pwhash = (await Util.toBuffer(hash)).toString('utf-8');
+        const pieces = pwhash.split('$');
+        const expect = 'm=' + (memlimit >> 10) + ',t=' + opslimit + ',p=1';
+        if (expect.length !== pieces[3].length) {
+            return true;
+        }
+        return !crypto.timingSafeEqual(
+            await Util.toBuffer(expect),
+            await Util.toBuffer(pieces[3])
+        );
+    }
+};