Java AES Cipher

AESCipher.java

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;
import java.security.SecureRandom;
import java.security.MessageDigest;
import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.security.InvalidKeyException;
import javax.crypto.BadPaddingException;
import java.security.InvalidAlgorithmParameterException;

public class AESCipher {
    private static final int IV_SIZE = 16;
    private SecretKeySpec secretKeySpec;
    public AESCipher(String key) throws UnsupportedEncodingException, NoSuchAlgorithmException {
        // Hashing key.
        MessageDigest digest = MessageDigest.getInstance("SHA-256");
        digest.update(key.getBytes("UTF-8"));
        byte[] keyBytes = new byte[32];
        System.arraycopy(digest.digest(), 0, keyBytes, 0, keyBytes.length);
        secretKeySpec = new SecretKeySpec(keyBytes, "AES");
    }

    public String encrypt(String plainText) throws IllegalBlockSizeException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, BadPaddingException, InvalidAlgorithmParameterException{
        byte[] clean = plainText.getBytes();

        // Generating IV.
        byte[] iv = new byte[IV_SIZE];
        SecureRandom random = new SecureRandom();
        random.nextBytes(iv);
        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);

        // Encrypt.
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
        byte[] encrypted = cipher.doFinal(clean);

        // Combine IV and encrypted part.
        byte[] encryptedIVAndText = new byte[IV_SIZE + encrypted.length];
        System.arraycopy(iv, 0, encryptedIVAndText, 0, IV_SIZE);
        System.arraycopy(encrypted, 0, encryptedIVAndText, IV_SIZE, encrypted.length);

        return new String(Base64.getEncoder().encode(encryptedIVAndText));
    }

    public String decrypt(String inputText) throws InvalidKeyException, IllegalBlockSizeException, NoSuchAlgorithmException, InvalidAlgorithmParameterException, BadPaddingException, NoSuchPaddingException{
        // Extract IV.
        byte[] iv = new byte[IV_SIZE];
        byte[] encryptedIvTextBytes = Base64.getDecoder().decode(inputText);
        System.arraycopy(encryptedIvTextBytes, 0, iv, 0, iv.length);
        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);

        // Extract encrypted part.
        int encryptedSize = encryptedIvTextBytes.length - IV_SIZE;
        byte[] encryptedBytes = new byte[encryptedSize];
        System.arraycopy(encryptedIvTextBytes, IV_SIZE, encryptedBytes, 0, encryptedSize);

        // Decrypt.
        Cipher cipherDecrypt = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipherDecrypt.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);
        byte[] decrypted = cipherDecrypt.doFinal(encryptedBytes);

        return new String(decrypted);
    }
}

Example of use

public class Main {


    public static void main(String[] args) throws Exception {
        AESCipher c = new AESCipher("123456789qwerty$");
        System.out.println(c.encrypt("FOO"));
        System.out.println(c.decrypt(c.encrypt("FOO")));

    }
}

Python counterpart https://gist.github.com/maxpowel/c5fdac919528e36f553732b507420408