An electronic signature is a type of electronic script, similar to a seal, used for signing electronic documents. Contracts and other legal forms as well as email messages commonly include an electronic signature. Word documents, such as those created with Microsoft Word or similar programs, also commonly include electronic signatures. Electronic signatures may be inserted into word documents as image files, such as jpg files. The image file is a digital representation of a person's handwritten signature. Electronic signatures can be simple images and text, or they can also be more secure encrypted digital signatures, which are harder to forge or fake. Due to the growth of e-commerce on the Internet, paper documents are often replaced with digital documents, requiring electronic signatures. United States federal and state laws, such as the Federal E-Sign Act of 2000, give legal validity to electronic signatures, making them just as valid under the law as handwritten signatures.