Hi guys,
I have big question. How to change this C# code to Apex. I tried but it didn't work. It always give me APEX_ERROR : System.InvalidParameterValueException: Invalid private key. Must be 16 bytes. Can somebody  help me, please. 

@RestResource(urlMapping='/API_test/*')
global class API_test{

    global class clsrecords{   	
        global String endpoint{get;set;}
        global String decrypt{get;set;}
    }
    //Get
    @HttpGet
    global static List<clsrecords> getrecords(){
        
        Date dToday = System.Today();
        Datetime myDateTime = Datetime.now();
        Datetime datetimee = myDateTime.addDays(277);
        String datee = datetimee.format('yyyyMMdd');
        
        String d = EncodingUtil.urlDecode('8806165303', 'utf8');
        string key = EncodingUtil.urlDecode(datee,'utf8');
        string iv = EncodingUtil.urlDecode('WGXVRMNU', 'utf8');
        
        Blob data = blob.valueof(d);
        Blob token_key = blob.valueof(key);
        Blob token_iv = blob.valueof(iv);
        
        //Blob decrypt = Crypto.decryptWithManagedIV('AES128', token_key, token_key);
        //Blob decrypt = Crypto.decrypt('AES256',token_key,token_iv,data);
        //Blob encrypt = Crypto.encrypt('AES128',data2,token_key,token_iv); 
        Blob encrypt = Crypto.encryptWithManagedIV('AES128', token_key, token_iv ); 
        
        List<clsrecords> lstcls = new List<clsrecords>();
        clsrecords cls = new clsrecords();
        cls.decrypt = String.valueof(encrypt);
        //cls.decrypt = String.valueof(data.size())+String.valueof(token_key.size())+String.valueof(token_iv.size());
        lstcls.add(cls);
        return lstcls;
    }
}