Cryptographic Systems

Cryptographic Systems

1. Securing Communications

   • Authentication, Integrity, and Confidentiality
     • To ensure secure communications across both the public and private infrastructure, the network administrator’s first goal is to secure
   • Authentication
     • Authentication guarantees that a message comes from the source that it claims to come from. Authentication is similar to entering a secure personal identification number
   • Data Integrity
   • ensures that messages are not altered in transit. With data integrity, the receiver can verify that the received message is identical to the sent message and that no manipulation occurred.
   • Cryptanalysis
     • Cryptanalysis is the practice and study of determining the meaning of encrypted information (cracking the code), without access to the shared secret key.

2. Basic Integrity and Authenticity

   • Cryptographic Hash Function
     • Hashes are used for integrity assurance. As shown in the figure, a hash function takes binary data, called the message
   • Well-Known Hash Functions
     • Hash functions are helpful when ensuring data is not changed accidentally, such as by a communication error.
   • Integrity with MD5, SHA-1, and SHA-2
   • HMAC Operation
     • the sending device inputs data (such as Terry Smith’s pay of $100 and the secret key)

3. Confidentiality

   • Two Classes of Encryption Algorithms
     • here are two approaches to ensuring the security of data when using encryption.
   • Symmetric and Asymmetric Encryption
     • To help understand the differences between the two types of algorithms,
   • Data Encryption Standard
     • Data Encryption Standard (DES) is a legacy symmetric encryption algorithm that usually operates in block mode by encrypting data in
   • Alternate Encryption Algorithms
   • RC Algorithms

4. Public Key Cryptography

   • Symmetric Versus Asymmetric Encryption
     • Asymmetric Key Algorithms
       • Internet Key Exchange (IKE), which is a fundamental component of IPsec VPNs. Secure Socket Layer (SSL), which is now implemented as IETF standard TLS.
     • Public Key + Private Key = Confidentiality
     • Private Key + Public Key = Authentication
   • Asymmetric Algorithms
     • Phase 1 - Confidentiality
     • Phase 2 - Authentication and Integrity
     • Types of Asymmetric Algorithms
       • Although the mathematics differ, these algorithms all have one thing in common;