1 files changed, 32 insertions, 0 deletions
diff --git a/library/sodium-plus/lib/backend.js b/library/sodium-plus/lib/backend.js
new file mode 100644
index 000000000..84466bf25
--- /dev/null
+++ b/library/sodium-plus/lib/backend.js
@@ -0,0 +1,32 @@
+const CryptographyKey = require('./cryptography-key');
+/* istanbul ignore if */
+if (typeof (Buffer) === 'undefined') {
+    let Buffer = require('buffer/').Buffer;
+}
+
+module.exports = class Backend {
+    constructor() {
+        // NOP
+        this.backendName = 'UndefinedBackend';
+    }
+
+    /**
+     * @param {CryptographyKey} sKey
+     * @param {CryptographyKey} pKey
+     * @return {Promise<CryptographyKey>}
+     */
+    async crypto_box_keypair_from_secretkey_and_publickey(sKey, pKey) {
+        /* istanbul ignore if */
+        if (sKey.getLength() !== 32) {
+            throw new Error('Secret key must be 32 bytes');
+        }
+        /* istanbul ignore if */
+        if (pKey.getLength() !== 32) {
+            throw new Error('Public key must be 32 bytes');
+        }
+        const keypair = Buffer.alloc(64);
+        sKey.getBuffer().copy(keypair, 0, 0, 32);
+        pKey.getBuffer().copy(keypair, 32, 0, 32);
+        return new CryptographyKey(Buffer.from(keypair));
+    }
+};