Implementacija algoritma LZP3 za kompresiju

undergraduate thesis

• Title (english): Implementation of the LZP3 compression algorithm
• Author: Lovro Grgurić Mileusnić
• Mentor: Stjepan Groš (mentor)
• Committee member: Stjepan Groš (predsjednik povjerenstva)
• Committee member: Mihael Marović (član povjerenstva)
• Committee member: Adrian Komadina (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2022-07-04, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing

Abstract

Tvrtka Siemens firmware za svoje logičke kontrolere isporučuje komprimiran izmijenjenom varijantom LZP3 algoritma. Opskurnost ove varijante predstavlja prepreku u sigurnosnom istraživanju i analizi jer je firmware nemoguće dekomprimirati standardnim alatima. Stoga istraživačima preostaje samo analiza pristupom crne kutije, za koji je potrebno imati pristup PLC sklopovlju na koje će se firmware učitati.
U ovom radu analiziran je općeniti LZP algoritam, njegove četiri izvorne varijante te teorijski model na kojem se algoritam zasniva. Opisana je specifikacija Siemens varijante LZP3 algoritma, odgovarajuća implementacija dekompresora te popratni modul za dekompresiju napisan u programskom jeziku Python.

Abstract (english)

Siemens provides compressed firmware with a modified version of the LZP3 algorithm for its programmable logic controllers. The obscurity of this variant presents an obstacle in security research and analysis because the firmware is impossible to decompress with standard decompression tools. Therefore, researchers can only apply a black box approach to analysis, which requires access to the PLC hardware on which the firmware will be loaded.
In this paper, the general LZP algorithm its variants and the underlying theoretical model are analysed. The specification of the Siemens variant of the LZP3 algorithm is described and a Python implementation of the decompressor was developed along with the accompanying decompression module.

• Keywords: programirljiv logički kontorleri; PLC; SCADA; kompresijski algoritmi; LZP3; sigurnost
• Keywords (english): programmable logic controllers; PLC; SCADA; compression algorithms; LZP3; security
• Language: croatian
• URN:NBN: urn:nbn:hr:168:410798
• Study programme: Title: Computing; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka računarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka računarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-01-15 10:14:43