Discrete mathematics : graph algorithms algebraic structures coding theory and cryptography Conveying ideas in a user friendly style this book has been designed for a course in Applied Algebra. The book covers graph algorithms basic algebraic structures coding theory and cryptography. It will be most suited for senior undergraduates and beginning graduate students in mathematics and computer science as also to individuals who want to have a knowledge of the below mentioned topics. Presents a description of private key cryptosystems as also a discussion on public key cryptosystems such as RSA ElGamal and Miller Rabin. Finally the Agrawal KayalSaxena algorithm (AKS Algorithm) for testing if a given positive integer is prime or not in polynomial time is presented the first time in a textbook.