finalize multi-device

WASignalGroup/sender_message_key.js

@@ -0,0 +1,39 @@
+const { deriveSecrets } = require('libsignal/src/crypto');
+class SenderMessageKey {
+    iteration = 0;
+
+    iv = Buffer.alloc(0);
+
+    cipherKey = Buffer.alloc(0);
+
+    seed = Buffer.alloc(0);
+
+    constructor(iteration, seed) {
+        const derivative = deriveSecrets(seed, Buffer.alloc(32), Buffer.from('WhisperGroup'));
+        const keys = new Uint8Array(32);
+        keys.set(new Uint8Array(derivative[0].slice(16)));
+        keys.set(new Uint8Array(derivative[1].slice(0, 16)), 16);
+        this.iv = Buffer.from(derivative[0].slice(0, 16));
+        this.cipherKey = Buffer.from(keys.buffer);
+
+        this.iteration = iteration;
+        this.seed = seed;
+    }
+
+    getIteration() {
+        return this.iteration;
+    }
+
+    getIv() {
+        return this.iv;
+    }
+
+    getCipherKey() {
+        return this.cipherKey;
+    }
+
+    getSeed() {
+        return this.seed;
+    }
+}
+module.exports = SenderMessageKey;