Electronic signatures, also known as e-signatures, are electronic representations of signatures used to signify approval in documents or other digital agreements. The rise of e-commerce on the Internet has led to an increase in the use of online agreements or other electronic documents which require an electronic signature. How an electronic signature is used and implemented depends on the type of agreement. An electronic signature may be an image based representation of an actual handwritten signature which is inserted at the end of a document to take the place of a physical signature. In other cases, an electronic signature may be captured by having a person sign an electronic signature pad or tablet. Electronic signatures may also be as simple as clicking an "agree" button on an online form or click through agreement. More complex electronic signatures may use digital encryption in order to protect the document from being changed or altered.