Rcon : is it a constant if AES is implemented on an FPGA?

[hassanzia]

HI, I'm trying to implement a 128-bit AES encryptor on an FPGA. My question is regarding the Rcon table used in the Rijndael key schedule. Is it constant for any key provided or does it need to be calculated on the fly? ie whether its independent of the key supplied or not?

PS If it is independent, would it be possible to implement this portion as a look up table in an fpga?

 

[cntube]

I looked at a python implementation and it looks to be a constant. OK then to have a LUT in rom block or so.

 

[mohammadreza2013]

hello hassanzia
in each round that you want to product new key you should use rcon and rotword and subbyte...
rcon depend on that witch round you want use it...in each round it difficult...