Function aes256cbcDecrypt

aes256cbcDecrypt(
    fileKey: ByteArray,
    ciphertext: ByteArray,
    iv?: ByteArray,
): Promise<ByteArray>
Decrypts data using AES-256-CBC mode.
Parameters
- fileKey: ByteArray
  The 32-byte decryption key.
- ciphertext: ByteArray
  The encrypted data to decrypt.
- iv: ByteArray = ...
  The 16-byte initialization vector. Defaults to zero IV.
Returns Promise<ByteArray>
A promise that resolves to the decrypted data.
Example
```
const decrypted = await aes256cbcDecrypt(key, ciphertext, iv)
```
- Defined in packages/pdf-lite/src/utils/algos.ts:240