Advanced Encryption Standard (AES) IP core implements Rijndael encryption and decryption algorithm as specified in Federal Information Processing Standard (FIPS) 197 from the National Institute of Standards and Technology (NIST). The parameterized cores can be compiled for either encryption or decryption or both encryption and decryption function and key expansion, supporting any or all proposed key sizes (128/192/256-bit). Core provide user the greatest possible flexibility due to the option of compile time parameters for configuring the core. These cores are designed to be simple to use and can be integrated into any AES design with minimum effort. Verilog source code or ASIC/FPGA netlist is available for the fully functional synchronous AES core. They support all cipher modes (ECB, CBC, CFB1, CFB8, CFB128, OCB and CTR) of AES defined in SP800-38A with or without key expander.