1 files changed, 51 insertions, 0 deletions
diff --git a/pkg/encryption.ts b/pkg/encryption.ts
new file mode 100644
index 0000000..c9f0e9d
--- /dev/null
+++ b/pkg/encryption.ts
@@ -0,0 +1,51 @@
+import { fromBase58 } from "../util/base58";
+
+export async function generateKey() {
+  return await crypto.subtle.generateKey(
+    {
+      name: "AES-GCM",
+      length: 128,
+    },
+    true,
+    ["encrypt", "decrypt"],
+  );
+}
+
+export async function encrypt(text: string): Promise<{ encrypted: Uint8Array; iv: Uint8Array; key: Uint8Array }> {
+  const key = await generateKey();
+
+  const iv = crypto.getRandomValues(new Uint8Array(16));
+
+  const encryptedBuffer = await crypto.subtle.encrypt(
+    {
+      name: "AES-GCM",
+      iv,
+    },
+    key,
+    new TextEncoder().encode(text),
+  );
+
+  const exportedKey = await crypto.subtle.exportKey("raw", key);
+  return {
+    encrypted: new Uint8Array(encryptedBuffer),
+    key: new Uint8Array(exportedKey),
+    iv,
+  };
+}
+
+export async function decrypt(encrypted: string, keyData: Uint8Array, iv: string, keyVersion: number): Promise<string> {
+  const algorithm = keyVersion === 1 ? "AES-CBC" : "AES-GCM";
+
+  const key = await crypto.subtle.importKey("raw", keyData, { name: algorithm, length: 128 }, false, ["decrypt"]);
+
+  const decrypted = await crypto.subtle.decrypt(
+    {
+      name: algorithm,
+      iv: fromBase58(iv),
+    },
+    key,
+    fromBase58(encrypted),
+  );
+
+  return new TextDecoder().decode(decrypted);
+}