Definition
A key schedule is an algorithm that generates subkeys from the original encryption key for symmetric encryption algorithms. Subkeys are a segment of the encryption and decryption procedure in block ciphers.
The key schedule concept has been a fundamental aspect of symmetric encryption since its inception. For example, it has been widely used in Data Encryption Standard (DES) since the 1970s.
Benefits of Using a Key Schedule
- Protection: A sophisticated key schedule generates distinct keys for every round, making it harder for hackers to comprehend the initial key.
- Effectiveness: Key schedules often produce subkeys in advance, resulting in faster encryption speed.
Drawbacks of Using a Key Schedule
- Complexity: A key schedule must balance computing efficacy with cryptographic strength. As a result, developing a safe key schedule needs advanced technical knowledge.
- Vulnerabilities: A poor key schedule might introduce recognizable patterns that cybercriminals can exploit to crack the encryption.
