Asymmetric vs Symmetric Cryptography 🔑🔒

Asymmetric Encryption:
- Strengths: Allows secure communication over untrusted channels.
- Weaknesses: Computationally expensive and complex.
- Use Case: Ideal for securely exchanging keys.
Symmetric Encryption:
- Strengths: Faster and more efficient for encrypting large amounts of data.
- Weaknesses: Requires a secure method to share the secret key.
- Use Case: Suitable for efficient data encryption once the key is securely exchanged.

Combination: Many secure communication systems use both types of encryption to leverage their strengths.
- Key Exchange: Asymmetric encryption is used to securely transmit the symmetric key.
- Data Encryption: Symmetric encryption is used for fast and efficient data encryption.

Purpose: Authenticate received messages and ensure data integrity.
- Difference from Digital Signatures: Uses a shared secret key for both generating and verifying the MAC.
- Example: HMAC (Keyed Hash Message Authentication Code).

Function: Uses a cryptographic hash function and a secret key.
- Hash Functions: SHA-1, MD5, etc.
- Process: Generate MAC, send with message, and verify by comparing computed MAC with received MAC.

Function: Uses a symmetric cipher and a shared key to generate a MAC.
- Block or Stream Ciphers: DES, AES.
- Process: Encrypt message using a block cipher in a specific mode.

Mechanism: Builds MACs using block ciphers in CBC mode.
- CBC Mode: Incorporates previously encrypted blocks into subsequent blocks.
- Integrity: Any modification to the plaintext results in a different final output, ensuring message integrity.

Asymmetric Encryption: Secure key exchange, but slower.
Symmetric Encryption: Fast data encryption, requires secure key sharing.
MACs: Ensure message authenticity and integrity.
- HMAC: Uses hash functions and a secret key.
- CMAC: Uses symmetric ciphers for MAC generation.
- CBC-MAC: Uses CBC mode to ensure data integrity.

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Last updated 3 months ago