The Elliptic Curve Digital Signature Algorithm (ECDSA) is a public key cryptosystem used for creation and verification of digital signatures in electronic documents. In this thesis, we created a Java applet that provides the functionality of the ECDSA using all of the NIST elliptic curves over GF(p). This applet was embedded into a website and tailored for public use across an online network. We show that Java can provide an effective platform for the ECDSA in combination with imported packages and classes. The implementation details of our ECDSA applet are discussed, followed by an analysis of the code functions.