Hi frenz Many of u must be using smartphonez and while usin u get a problem certificate error or certificate expiredwhile downloadin any content from other third party .So here iz ur solution to the problem as it would be d best solutuion because I too suffered this prob so as who know itz k but u need to know that smart phonez need a valid cer for using any app .And mostly the apps are old so they have a old certificate which matnot work with ur new phone so u need a certificate file and I will provide u all thiz merely for a word thankz what u need to do iz just email me ur name and ur imei no and model thiz is because every phone has a definite certificate so u need a certificate and a app called free signer which will sign ur filez as many people anyhow manage to get the certificate but itz damn hard to install thefree signer which itself posses a problem of cer error so if any of u need a workin certificate for ur phone and the app free signer just email me the following things imei no, model no and ur name to gopeabhijit85@gmail.com and within 3 dayz u will get the app free signer with ur phonez cer and key file if u donot believe jst try downloading the app free signer and install it u wont be ever sucessful u need my help i will definitely help u