Digital signature is widely used to implement many secure protocols. A digital signature has three parameters. They are the message, the key pair, and the signature. In general, the message is given. The key pair is chosen randomly by the signer. The signature is computed from the message and the key pair. But in some cases, we can choose the value of one of the parameters, this may make it possible to other applications such as blind signatures or subliminal channels. There are some researches to discuss the relations between the parameters and the applications of the digital signatures. In this research, we will propose three new schemes as examples of this technique. The first one is a fair blind signature scheme. The other two are subliminal channel schemes. These three new schemes have some important properties. The concept of this research may help the future researches to find new applications of the digital signature. Meanwhile, these new schemes can show that how the concept can help us to develop or improve applications.