Cryptography, the science of secret writing, is the biggest, baddest security tool in the application
programmer's arsenal. Cryptography provides three services that are crucial in secure programming.
These include a cryptographic cipher that protects the secrecy of your data; cryptographic certificates,
which prove identity (authentication); and digital signatures, which ensure your data has not been damaged or tampered with
Bạn cần tạo một khóa đối xứng từ một password để người dùng chỉ cần nhớ password và không cần lưu trữ khóa. Sử dụng lớp System.Security.Cryptography.PasswordDeriveBytes để tạo khóa đối xứng từ chuỗi password.
William Stallings' Cryptography and Network Security: Principles and Practice, 5e is a practical survey of cryptography and network security with unmatched support for instructors and students.
In this age of universal electronic connectivity, viruses and hackers, electronic eavesdropping, and electronic fraud, security is paramount. This text provides a practical survey of both the principles and practice of cryptography and network security.
As a companion book of Vaudenay's A Classical Introduction to Cryptography,
this exercise book contains a carefully revised version of most
of the material used in teaching by the authors or given as examinations
to the undergraduate students of the Cryptography and Security lecture
at EPFL from 2000 to mid-2005. It covers a majority of the subjects that
make up today's cryptology, such as symmetric or public-key cryptography,
cryptographic protocols, design, cryptanalysis, and implementation
During the last three decades, public academic research in cryptography has exploded.
While classical cryptography has been long used by ordinary people, computer
cryptography was the exclusive domain of the world’s militaries since the World War
II. Today, state-of the-art computer cryptography is practiced outside the secured
walls of the military agencies. The laypersons can now employ security practices that
can protect against the most powerful adversaries.
As technology progresses and as more and more personal data is digitized, there is even more of an emphasis required
on data security today than there has ever been. Protecting this data in a safe and secure way which does not impede the
access of an authorized authority is an immensely difficult and very interesting research problem. Many attempts have
been made to solve this problem within the cryptographic community.
In this book, we present one of these data security methods known as visual cryptography (VC).
Cryptography (or cryptology; from Greek κρυπτός, "hidden, secret"; and γράφειν, graphein, "writing", or -λογία, -logia, "study", respectively) is the practice and study of techniques for secure communication in the presence of third parties (called adversaries). More generally, it is about constructing and analyzing protocols that overcome the influence of adversaries
Chương 7 - Cryptography basics and methods (Mật mã và các phương pháp). Nội dung chính trình bày trong chương này gồm có: Tổng quan về mật mã, các thuật giải mã hóa, các hệ thống mã hóa, kiến trúc hạ tầng khóa công cộng, đối phó với các tấn công mã hóa.
This paper presents an approach related to authenticate mutually a RFID (Radio Frequency Identification) tag from a RFID reader by using the cryptography based on Elliptic curve. Our proposal mutual authentication lies on the Elliptic curve discrete logarithm problem, which is considered the core in order to fight against all of attacks like replay attack, forgery attack and man-in-the-middle attack. Scientifically, we prove not only the accuracy and the security of our approach, but also its performance in the mutual authentication between a RFID tag and a reader. ...
To use data encryption algorithms in network communications, all parities must first agree on using the same secret keys
Rely on couriers
Set up a meeting to determine a secret key
Use postal service, email service, phone service
However, these conventional methods are inflexible for network communication applications
Public-key cryptography (PKC)
Invented in the 1970’s
Without the need of sharing prior secrets to distribute secret keys securely
Can also be used for authentication
traditional private/secret/single key cryptography uses one key
Key is shared by both sender and receiver
if the key is disclosed communications are compromised
also known as symmetric, both parties are equal
hence does not protect sender from receiver forging a message & claiming is sent by sender
Objectives of Chapter 7: To distinguish between two cryptosystems; to introduce trapdoor one-way functions and their use in asymmetric-key cryptosystems; to introduce the knapsack cryptosystem as one of the first ideas in asymmetric-key cryptography; to discuss the RSA cryptosystem.
(BQ) Appropriate for undergraduate and graduate level courses in Cryptography and Computer security. Best-selling author and two-time winner of the TEXTY award for the best Computer Science and Engineering text, William Stallings provides a practical survey of both the principles and practice of cryptography and network security. This text, which won the 1999 TAA Award for the best computer science and engineering textbook of the year, has been completely updated to reflect the latest developments in the field.
Cryptography – science of encrypting information.
“scrambles” data so only authorized parties can “unscramble” and read data using two methods
Can substitute – change one letter with a different letter
Can transpose – scramble the order of letters, without actually changing one for another.
The best cryptosystems both substitute and transpose.
Visual next slide