This book, based on the author's Ph.D. thesis, was selected during the 1995 GI Doctoral Dissertation Competition as the winning thesis in the foundations-of-informatics track. Securing integrity for digital communications in the age of global electronic information exchange and electronic commerce is vital to democratic societies and a central technical challenge for cryptologists. As core contribution to advancing the state of the art, the author develops the new class of digital fail-stop signatures. This monograph is self-contained regarding the historical background and cryptographic primitives used. For the first time, a general and sophisticated framework is introduced in which innovative fail-stop signatures are systematically presented and evaluated, from theoretical foundations to engineering aspects.