Original: AES has a fixed block size of 128 bits and a key size of 128 , 192 , or 256 bits , whereas Rijndael can be specified with block and key sizes in any multiple of 32 bits , with a minimum of 128 bits and a maximum of 256 bits .
Simplified: AES has a fixed block sizes of 128 bits and three values of key size 128 , 192 , or 256 bits .