# ORYX (encryption algorithm)

(Redirected from ORYX)

ORYX is an encryption algorithm used in cellular communications in order to protect data traffic. It is a stream cipher designed to have a very strong 96-bit key strength with a way to reduce the strength to 32-bits for export. However, due to mistakes the actual strength is a trivial 16-bits and any signal can be cracked after the first 25-27 bytes.[1]

## Algorithm Description

ORYX is a simple stream cipher based on binary linear feedback shift registers (LFSRs) to protect cellular data transmissions(for wireless data services). The cipher ORYX has four components: three 32-bit LFSRs which labeled as LFSRA, LFSRB and LFSRK, and an S-box containing a known permutation P of the integer values 0 to 255.

•The feedback function for LFSRK is defined as:

Lt+32= Lt+28⊕Lt+19⊕Lt+18⊕Lt+16⊕Lt+14⊕Lt+11⊕Lt+10⊕Lt+9⊕Lt+6⊕Lt+5⊕Lt+1⊕Lt

•The feedback functions for LFSRA are defined as:

Lt+32=Lt+26⊕Lt+23⊕Lt+22⊕Lt+16⊕Lt+12⊕Lt+11⊕Lt+10⊕Lt+8⊕Lt+7⊕Lt+5⊕Lt+4⊕Lt+2⊕Lt+1⊕Lt

and

Lt+32=Lt+27⊕Lt+26⊕Lt+25⊕Lt+24⊕Lt+23⊕Lt+22⊕Lt+17⊕Lt+13⊕Lt+11⊕Lt+10⊕Lt+9⊕Lt+8⊕Lt+7⊕Lt+2⊕Lt+1⊕Lt

•The feedback function for LFSRB is:

Lt+32=Lt+31⊕Lt+21⊕Lt+20⊕Lt+16⊕Lt+15⊕Lt+6⊕Lt+3⊕Lt+1⊕Lt