Function gcmEncrypt

gcmEncrypt(
    key: ArrayBuffer | Uint8Array<ArrayBufferLike>,
    iv: ArrayBuffer | Uint8Array<ArrayBufferLike>,
    plaintext: ArrayBuffer | Uint8Array<ArrayBufferLike>,
    aad?: ArrayBuffer | Uint8Array<ArrayBufferLike>,
    tagLength?: number,
): GcmEncryptResult
Encrypt data using AES-GCM with optional AAD (Additional Authenticated Data)
Parameters
- key: ArrayBuffer | Uint8Array<ArrayBufferLike>
  Encryption key (16/24/32 bytes for AES-128/192/256)
- iv: ArrayBuffer | Uint8Array<ArrayBufferLike>
  Initialization vector (recommended 12 bytes)
- plaintext: ArrayBuffer | Uint8Array<ArrayBufferLike>
  Data to encrypt
- Optionalaad: ArrayBuffer | Uint8Array<ArrayBufferLike>
  Optional additional authenticated data (authenticated but not encrypted)
- OptionaltagLength: number
  Optional authentication tag length in bytes (default: 16, range: 4-16)
Returns GcmEncryptResult
Object containing ciphertext and authentication tag
Example
```
const crypto = import.meta.use('crypto');

const key = crypto.randomBytes(32);  // AES-256
const iv = crypto.randomBytes(12);   // 12 bytes IV for GCM
const plaintext = new TextEncoder().encode('Hello, World!');
const aad = new TextEncoder().encode('Additional authenticated data');

// Without AAD
const encrypted1 = crypto.gcmEncrypt(key, iv, plaintext);

// With AAD
const encrypted2 = crypto.gcmEncrypt(key, iv, plaintext, aad);

// With custom tag length
const encrypted3 = crypto.gcmEncrypt(key, iv, plaintext, aad, 12);
```