Cryptography, which translates as "secret writing," refers to the science of concealing the meaning of data so only specified parties understand a transmission's contents. Cryptography has existed for thousands of years; for most of history, however, the users of cryptography were associated with a government or organized group and were working to conceal secret messages from enemies. These days, millions upon millions of secure, encoded transmissions happen online each day -- and cryptographic standards are used to protect banking data, health information, and much more. Without cryptography, e-commerce as we know it would be impossible. Since online security threats evolve so quickly, there are dozens of different schools of thought on how best to use encryption to enhance network security -- not just for governments, but for businesses and end users, too.
Classical Encryption Techniques
- Classical Encryption Techniques Explained at Purdue University (PDF): These lecture notes describe historical encryption methods and how they are used today.
- Analysis and Elements of Various Classical Encryption Techniques (PDF): This presentation provides detailed historical information on various forms of encryption.
- Introduction to Classical Cryptography by Noted Textbook Author: This overview includes information on how classical cryptography techniques relate to the modern day.
- Integration of Classical and Modern Encryption Techniques (PDF): This research report seeks to discover and discuss effective ways to integrate classical and new encryption.
- Basic Introduction to Cryptographic Finite Fields: This detailed inquiry discusses both finite fields and alternative ways of implementing the same forms of cryptography.
- Storing Cryptographic Data in the Galois Field (PDF): This report discusses the Galois Field, an important evolution on the concept of cryptographic finite fields.
- Comparing Finite Fields to Elliptic Curve Encryption (PDF): This essay focuses on how elliptic curve encryption could be used to build on and enhance finite fields.
- Finite Field Arithmetic for Cryptography (PDF): This essay describes advanced methods of using finite field arithmetic to develop algorithms for cryptographic purposes.
Advanced Encryption Standard
- Overview and Presentation on the History of AES (PDF): This series of presentation slides serves as an introduction to the very powerful AES encryption standard.
- Detailed Technical Review of the Advanced Encryption Standard: This page provides a historical background of AES and summary of how the different components work.
- Research Report Reviewing AES and Different Implementations (PDF): This illustrated guide demonstrates one conventional method of implementing AES in programming.
- Technical Guide to Intel's Implementation of AES (PDF): This official Intel white paper discusses how AES is implemented within modern Intel technology.
Confidentiality Using Symmetric Encryption
- Symmetric Versus Asymmetric Encryption Discussed (PDF): This set of lecture notes discusses the pros and cons of "secret key" versus "public key" encryption.
- Detailed Discussion of Symmetric Encryption and RSA Algorithms (PDF): This technical review of symmetric encryption implementation discusses algorithms in detail.
Number Theory and Hash Algorithms
- Hash Functions in Cryptography (PDF): These detailed, illustrated notes meant for college students introduce hash algorithms and their function in data security.
- Number Theory and Cryptography at Cornell (PDF): This set of notes and problems introduces advanced number theory concepts and tests comprehension.
- Applied Number Theory in Cryptography (PDF): This introduction to number theory goes into great depth about its many applications in the cryptographic world.
- Report on Hash Function Theory, Attacks, and Applications (PDF): This research report examines and compares cryptographic hash functions like MD5 and SHA-1.
- Hash Functions and Cryptography in Business: This article specifically discusses the importance and applications of hash functions in the business world.
- Verifiable Encryption of Digital Signatures (PDF): This scholarly essay reports on the current methods of digital signature verification and offers one new potential alternative.
- Overview of Digital Signatures: This page includes a straightforward introduction to digital signatures, their usage, and the various aspects of making them work.
- Discussion of Digital Signature Implementation and Issues (PDF): These notes approach the problems of digital signatures in terms of replicating the authenticity of "real" ones.
- Overview of Public Key Encryption: This discussion of public key encryption and the RSA algorithm draws from classic digital signature literature and theories.
- Basics of Understanding Digital Signatures: This overview from the U.S. federal government's "US-CERT" security team provides accessible information for consumers.
- Future Applications of Quantum Digital Signatures (PDF): This essay is an interpretation of how advanced digital signatures can be implemented with current technology.
- Authentication Applications: Kerberos and Public Key Infrastructure (PDF): This report discusses two of the most powerful authentication applications and how they can be implemented to enhance security.
- Information on Kerberos Protocol from MIT: This detailed overview of the Kerberos protocol provides information on its various releases and how to implement it.
- The Official Kerberos Consortium: This is the official "watchdog" organization that develops and publishes standards for the authentication application named Kerberos.
- Public Key Infrastructure Defined and Described at PC Magazine: This is an overview of Public Key Infrastructure (PKI) and how it is used to secure information.
- Public Key Infrastructure Approaches to Security: This documentation from Oracle discusses the elements of PKI and how they can be used in different technical scenarios.
- Auditing and Certification of a Public Key Infrastructure: This report defines the structure and process of using PKI and delves into some of its historical issues.
Electronic Mail Security
- The OpenPGP Alliance for Electronic Mail Encryption: This is the site of a nonprofit organization that maintains OpenPGP, a popular email encryption standard.
- Berkeley Lab Recommendations on Implementing Electronic Mail Security: These recommendations from the Lawrence Berkeley National Laboratory can be adapted for use by consumers and enterprises by using the cryptographic resources suggested.
- GnuPG Nonprofit Privacy Application for Linux-Based Systems: Based on the PGP concept, GnuPG is a nonprofit method of implementing email encryption in Linux-based systems.
- Basic Primer on Email Security for Consumers from CNBC: This report from news network CNBC discusses the issues around email encryption and security as they relate to consumers in a world of ever-increasing electronic spying.
IP Security and Web Security
- IP Security and Encryption Overview from Cisco Systems: This detailed information on the IPSec protocol and related security matters comes from Cisco, one of the top brands in hardware and software for online security.
- HTTP vs. HTTPS Comparison: This page is an introduction to "secure" HTTP connections (HTTPS) and how they differ from basic HTTP connections.
- What is SSL and What Are Certificates?: This page expands further on the concept of SSL and how "security certificates" work to authenticate the transfer of sensitive data.
- Summary Overview of SSL and How Related Protocols Work Together (PDF): This illustrated guide goes a step further by describing how SSL interacts with other protocols.
- What is a Firewall and What Types of Firewalls Are There?: This introduction serves to define and compare the different kinds of firewalls and how they operate.
- Basic Concepts for Managing a Firewall: Aimed at network administrators, this guide digs deep into the fundamental concepts to master in order to make a firewall effective.
- How Firewalls Work and How to Use Them: This introduction summarizes the basics of firewalls, some specialized types, and how a firewall "rule" should be designed.
- Basic Firewall Information and Use for Consumers: This overview from the nonprofit "Get Safe Online" helps consumers understand fundamental firewall concepts and use.