Project Summary: This is a little introduction about the subject. In public of real word, signatures are very widespread in use of tie certifier to something that you are the signatory. Using digital signatures in contracts and e-commerce are very common and has the same purpose as the handwriting signatures. The legal purpose of digital signatures is approving the person who signs the documents, shows which documents will be signed in a manner that could not change and in e-commerce to guarantee both the customer and the seller can be guaranty to the identity of the other also encrypts a message that you want only the recipient of the message to see. The digital signature is not as a written signature is difficult to penetrate, and in written signatures, you can cut off part of the document as opposed to digital signatures. This paper will discuss the case of abusing stolen trusted digital code certificates.