Invalid argument(s): Initialization vector must be the same length as block size

[NaarGes]

Hi, when I run the below code it causes error: Invalid argument(s): Initialization vector must be the same length as block size
but if I replace 32 with 16 in both key and iv it gives me result without error. why is that?

final plainText = data.toString();
    final key = Key.fromLength(32);
    final iv = IV.fromLength(32);
    final aesEncrypter = Encrypter(AES(key, mode: AESMode.cbc));
    final encryptedJson = aesEncrypter.encrypt(plainText, iv: iv);

I'm using encrypt: ^5.0.3 version

full error log

 [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Invalid argument(s): Initialization vector must be the same length as block size
E/flutter ( 8817): #0      CBCBlockCipher.init (package:pointycastle/block/modes/cbc.dart:52:7)
E/flutter ( 8817): #1      PaddedBlockCipherImpl.init (package:pointycastle/padded_block_cipher/padded_block_cipher_impl.dart:47:12)
E/flutter ( 8817): #2      AES.encrypt (package:encrypt/src/algorithms/aes.dart:40:9)
E/flutter ( 8817): #3      Encrypter.encryptBytes (package:encrypt/src/encrypter.dart:12:19)
E/flutter ( 8817): #4      Encrypter.encrypt (package:encrypt/src/encrypter.dart:28:12)
E/flutter ( 8817): #5      KonectPlateEncrypter.getEncryptedData (package:marginal_parking_app/data/encrypter.dart:20:40)