Class Decrypt

ZezeJava/ZezeJava/src/main/java/Zeze/Net/Decrypt.java:9–112

import org.jetbrains.annotations.NotNull;

public class Decrypt implements Codec {
	private final @NotNull Codec sink;
	private final @NotNull Cipher cipher;
	private final @NotNull ByteBuffer ivr;
	private final @NotNull ByteBuffer ivw;
	private final byte @NotNull [] iv;
	private final byte @NotNull [] in;
	private final byte @NotNull [] out;
	private int count = 0;

	public Decrypt(@NotNull Codec sink, byte @NotNull [] key) throws CodecException {
		this.sink = sink;
		iv = new byte[16];
		in = new byte[16];
		out = new byte[16];
		System.arraycopy(Digest.md5(key), 0, iv, 0, 16);
		ivr = ByteBuffer.wrap(iv);
		ivw = ByteBuffer.wrap(iv);
		try {
			cipher = Cipher.getInstance("AES/ECB/NoPadding");
			cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(iv, "AES"));
		} catch (Exception e) {
			throw new CodecException(e);
		}
	}

	private void succeed() {
		try {
			cipher.update(ivr, ivw);
			ivr.clear();
			ivw.clear();
		} catch (ShortBufferException e) {
			// skip
		}
	}

	@Override
	public void update(byte c) throws CodecException {
		if (count < 0) {
			sink.update((byte)(iv[count + 16] ^ c));
			iv[count++ + 16] = c;
			return;
		}
		in[count++] = c;
		if (count < 16)
			return;
		succeed();
		for (int i = 0; i < 16; i++) {
			out[i] = (byte)(iv[i] ^ in[i]);
			iv[i] = in[i];
		}
		sink.update(out, 0, 16);
		count = 0;
	}

	@Override
	public void update(byte @NotNull [] data, int off, int len) throws CodecException {
		int i = off;