Danni-Tech

Making the Complicated Simple

Security Plus PKI - SYMMETRIC ENCRYPTION

  • Key Points from This Video on Symmetric Encryption:

    • What is Encryption?

      • Encryption provides confidentiality, ensuring that only the intended party can access and read the data.
      • The process involves converting plaintext (e.g., “friend”) into ciphertext using an encryption algorithm.
      • To return the ciphertext to its original form, a decryption algorithm is applied.

    • Why Simple Encryption Isn’t Enough:

      • Basic encryption without additional security can be vulnerable because anyone with access to the algorithm could potentially decrypt the data.
      • Key-based encryption introduces a secret key to ensure only authorized parties can decrypt the ciphertext.

    • The Role of the Secret Key:

      • A secret key is a random set of ones and zeros.
      • Even if multiple people encrypt the same word using the same algorithm, different keys will produce different ciphertexts.
      • This randomness helps maintain data confidentiality.

    • Types of Key-Based Encryption:

      1. Symmetric Encryption: Uses the same key for both encryption and decryption.
      2. Asymmetric Encryption: Uses different keys for encryption and decryption (covered in the next video).

    • How Symmetric Encryption Works (Example):

      • Encrypting the word “friend” using a simple substitution cipher (shifting each letter forward by 4 spaces):
        • F → J
        • R → V
        • I → M
        • E → I
        • N → R
        • D → H
      • The ciphertext becomes “JVMIRH.”
      • To decrypt, the same key is used, shifting letters backward by 4 spaces to return to “friend.”

    • Pros and Cons of Symmetric Encryption:

      • Advantages:
        1. Faster than asymmetric encryption due to simpler mathematics and smaller key sizes.
        2. The ciphertext size is the same as the plaintext, making it efficient.
        3. Ideal for bulk data transfer, especially when securing large amounts of data quickly.
      • Drawbacks:
        1. Requires sharing the same key between parties, increasing the risk of key exposure.
        2. Less secure than asymmetric encryption when it comes to key distribution.

    • Common Symmetric Encryption Algorithms:

      • DES and RC4: Use small key sizes, making them vulnerable to attacks (deprecated).
      • 3DES: Uses a 168-bit key, offering more security than DES/RC4 but is only considered somewhat secure today.
      • AES and ChaCha20: Highly secure and efficient, considered the standard for modern encryption.