Function aes256cbcEncrypt

aes256cbcEncrypt(
    fileKey: ByteArray,
    block: ByteArray,
    iv?: ByteArray,
): Promise<ByteArray>
Encrypts data using AES-256-CBC mode.
Parameters
- fileKey: ByteArray
  The 32-byte encryption key.
- block: ByteArray
  The data to encrypt.
- iv: ByteArray = ...
  The 16-byte initialization vector. Defaults to zero IV.
Returns Promise<ByteArray>
A promise that resolves to the encrypted data.
Example
```
const encrypted = await aes256cbcEncrypt(key, plaintext, iv)
```
- Defined in packages/pdf-lite/src/utils/algos.ts:214