Re: [IPsec] IV in ESP packets for AES-CBC and AES-CTR methods

[Dan McDonald <danmcd at sun.com>]

On Mon, May 11, 2009 at 07:40:22PM +0530, ss murthy nittala wrote:
> Hi,
> Is it required for IV to be randomly generated for each ESP packet in  
> case of AES-CTR and AES-CBC methods?

I don't know about AES-CTR, but definitely in AES-CBC.

> AES-CBC:Is it required for IV to be randomly generated for each of the 
> outgoing ESP packets?In any case i think the packet shall include IV.

The AES-CBC packets include an IV of 16 bytes (i.e. one AES block) which must
be randomly generated.

Dan