INFORMATION SECURITY AND AUDIT
1. Overview of information security
2. Information and Network Security Policies
3. Cryptography and PKI
4. Network security applications
5. Design Principles
6. Compliance, Evaluation system and Law
7. Malicious logic and attacks
8. Vulnerability analysis and IT Audit
9. Intrusion detection and log analysis
LAB WORK -ISA
SOLVED PRACTICE QUESTIONS
PREV NEXT

SESSION KEY AND INTERCHANGE KEY

Session Key

A session key is a symmetric encryption key that is used for a single session of communication between two parties. It is typically generated for a specific session and discarded afterwards.

Characteristics:

  • Temporary: Only valid for the duration of a communication session.
  • Symmetric Key: Same key is used for both encryption and decryption.
  • High-Speed: Symmetric encryption with session keys is computationally efficient, suitable for encrypting large amounts of data.

Usage:

  1. Efficiency: Due to its symmetric nature, session keys enable fast encryption and decryption, making them suitable for encrypting the actual data transmitted during a session.
  2. Security: Limiting the key’s lifespan to a single session reduces the risk of key compromise affecting multiple sessions.

Example:

  • In a secure web communication using HTTPS, a session key is generated for encrypting data transferred between a client and a server during a single browsing session.

Interchange Key (Key Exchange Key)

An interchange key, often called a key exchange key, is used specifically for securely exchanging session keys between parties. These are usually asymmetric keys.

Characteristics:

  • Longer Lifespan: Typically, interchange keys are valid for longer periods than session keys.
  • Asymmetric Key: Uses a pair of public and private keys for encryption and decryption.
  • Security: Ensures that session keys can be exchanged securely over an insecure channel.

Usage:

  1. Key Exchange: The primary purpose is to securely distribute session keys. The public key of the recipient is used to encrypt the session key, and the recipient’s private key is used to decrypt it.
  2. Initial Authentication: Used in protocols to establish an initial secure connection, after which session keys take over for bulk data encryption.

Example:

  • In the SSL/TLS protocol, RSA or Diffie-Hellman keys are used as interchange keys to securely exchange the session keys that will be used for encrypting data during the session.

Working of Session Key and Interchange Key

  1. Key Exchange Phase:

    • The sender generates a session key for symmetric encryption.
    • The session key is encrypted using the recipient’s public interchange key.
    • The encrypted session key is sent to the recipient.

  2. Data Transfer Phase:

    • The recipient uses their private interchange key to decrypt and obtain the session key.
    • Both parties now have the same session key and use it for encrypting and decrypting the actual data exchanged during the session.
PREV NEXT