What is the key size and IV value for the lightweight symmetric stream cipher Rabbit?

The Rabbit cipher is designed as a lightweight symmetric stream cipher with a specific key size and initialization vector (IV). The key size for Rabbit is 128 bits, which provides a strong level of security suitable for various applications, particularly in constrained environments where performance is crucial. The initialization vector (IV) used with Rabbit is 64 bits, which is utilized during the encryption process to ensure that even if the same plaintext is encrypted multiple times with the same key, the resulting ciphertext will vary, enhancing security against certain types of cryptographic attacks.

This combination of 128-bit key size and 64-bit IV is optimal for maintaining a balance between security and performance in the intended contexts where Rabbit is deployed, such as in embedded systems and applications requiring lightweight cryptographic solutions.