✨ File upload frontpage and download decryption

DysonNetwork.Drive/Client/src/views/secure.ts

@@ -0,0 +1,92 @@
+export async function downloadAndDecryptFile(
+  url: string,
+  password: string,
+  onProgress?: (progress: number) => void
+): Promise<void> {
+  const response = await fetch(url);
+  if (!response.ok) throw new Error(`Failed to fetch: ${response.status}`);
+
+  const contentLength = +(response.headers.get('Content-Length') || 0);
+  const reader = response.body!.getReader();
+  const chunks: Uint8Array[] = [];
+  let received = 0;
+
+  while (true) {
+    const { done, value } = await reader.read();
+    if (done) break;
+    if (value) {
+      chunks.push(value);
+      received += value.length;
+      if (contentLength && onProgress) {
+        onProgress(received / contentLength);
+      }
+    }
+  }
+
+  const fullBuffer = new Uint8Array(received);
+  let offset = 0;
+  for (const chunk of chunks) {
+    fullBuffer.set(chunk, offset);
+    offset += chunk.length;
+  }
+
+  const decryptedBytes = await decryptFile(fullBuffer, password);
+
+  // Create a blob and trigger a download
+  const blob = new Blob([decryptedBytes]);
+  const downloadUrl = URL.createObjectURL(blob);
+  const a = document.createElement('a');
+  a.href = downloadUrl;
+  a.download = 'decrypted_file'; // You may allow customization
+  document.body.appendChild(a);
+  a.click();
+  a.remove();
+  URL.revokeObjectURL(downloadUrl);
+}
+
+export async function decryptFile(
+  fileBuffer: Uint8Array,
+  password: string
+): Promise<Uint8Array> {
+  const salt = fileBuffer.slice(0, 16);
+  const nonce = fileBuffer.slice(16, 28);
+  const tag = fileBuffer.slice(28, 44);
+  const ciphertext = fileBuffer.slice(44);
+
+  const enc = new TextEncoder();
+  const keyMaterial = await crypto.subtle.importKey(
+    'raw', enc.encode(password), { name: 'PBKDF2' }, false, ['deriveKey']
+  );
+  const key = await crypto.subtle.deriveKey(
+    { name: 'PBKDF2', salt, iterations: 100000, hash: 'SHA-256' },
+    keyMaterial,
+    { name: 'AES-GCM', length: 256 },
+    false,
+    ['decrypt']
+  );
+
+  const fullCiphertext = new Uint8Array(ciphertext.length + tag.length);
+  fullCiphertext.set(ciphertext);
+  fullCiphertext.set(tag, ciphertext.length);
+
+  let decrypted: ArrayBuffer;
+  try {
+    decrypted = await crypto.subtle.decrypt(
+      { name: 'AES-GCM', iv: nonce, tagLength: 128 },
+      key,
+      fullCiphertext
+    );
+  } catch {
+    throw new Error("Incorrect password or corrupted file.");
+  }
+
+  const magic = new TextEncoder().encode("DYSON1");
+  const decryptedBytes = new Uint8Array(decrypted);
+  for (let i = 0; i < magic.length; i++) {
+    if (decryptedBytes[i] !== magic[i]) {
+      throw new Error("Incorrect password or corrupted file.");
+    }
+  }
+
+  return decryptedBytes.slice(magic.length);
+}