Understanding Rijndael With AES for the CISSP Exam

Rijndael can use different block sizes, but AES uses a fixed block size of 128-bits.

So for AES, the block size must always be 128-bits!!!

Key Size Block Size

128 128

192 128

256 128

Basic Information for Rijndael

• Official NIST standard

• Won first place out of 15 other AES contestants

• Pronounced “Rhine Dall”

• Named after its developers Vincent Rijmen and Joan Daemen

• Rijndael is the actual name of the algorithm, AES is the standard

• Symmetric block cipher

• Proved to have the best security, speed, and scalability

• Stronger than DES and 3DES

• Supports 128, 192, 256-bit keys

Can be used by the government to protect sensitive but unclassified data as well as secret and top secret. Rijndael allows the use of block size same as key size.

Real-World Usage Examples (Added Section)

Where Rijndael / AES Is Actually Used

• Full Disk Encryption AES is used in BitLocker (Windows), FileVault (macOS), and LUKS (Linux) to encrypt entire hard drives and SSDs.

• VPNs and Secure Tunnels IPSec VPNs commonly use AES-128 or AES-256 for bulk data encryption after key exchange is completed.

• Cloud Data Protection Major cloud providers use AES to encrypt data at rest in object storage, block storage, and managed databases.

• TLS Encrypted Traffic Once the TLS handshake completes, symmetric encryption such as AES is used for fast, ongoing session encryption.

• Government and Regulated Environments AES is approved for protecting sensitive but unclassified, secret, and top secret information depending on key size.