What key sizes can be used with AES encryption?

The key sizes that can be used with AES (Advanced Encryption Standard) encryption are 128 bits, 192 bits, and 256 bits. AES is a symmetric encryption algorithm established by NIST, and it supports these three key lengths, which provide different levels of security.

Using a longer key length, such as 192 bits or 256 bits, increases the security of the encryption by making it more difficult for an attacker to perform a brute-force attack. The choice of key length allows an organization to balance the need for security against performance considerations, as longer keys require more computational power for both encryption and decryption.

Key sizes of 64 bits or 512 bits are not applicable to AES. A 64-bit key size is more characteristic of older encryption standards, like DES (Data Encryption Standard), while a 512-bit key is beyond what AES supports and generally involves other cryptographic systems that are not AES. Thus, the only valid key sizes for AES are indeed 128 bits, 192 bits, and 256 bits.