加密求助

还是以前的那一帖的问题
某类lua脚本中有一行代码：
local ckey =SecretKey({httpkey,rndsalt,actb.AllowUse,string.format("%.2f",actb.Dayleft),actb.DoTime});
找了很久经过虎友提醒得知SecretKey是软件里面自定义的函数并非lua函数

反编译软件得到以下关键代码：
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

public class ao implements ar {
protected Mac a;
protected int b;
protected String c;

public ao(String str) {
    this.c = str;
    try {
        this.a = Mac.getInstance(str);
        this.b = this.a.getMacLength();
    } catch (Throwable e) {
        throw new RuntimeException(e);
    }
}

public void a(byte[] bArr, int i, int i2) {
    try {
        this.a.update(bArr, i, i2);
    } catch (Throwable e) {
        throw new RuntimeException(e);
    }
}

public byte[] a() {
    return this.a.doFinal();
}

public byte[] a(byte[] bArr) {
    return this.a.doFinal(bArr);
}

public int b() {
    return this.b;
}

public void b(byte[] bArr) {
    try {
        this.a.init(new SecretKeySpec(bArr, this.c));
    } catch (Throwable e) {
        throw new RuntimeException(e);
    }
}

}

请问这个加密算法能否解密
我悄悄的走开正如我悄悄的来