Denis Periša (born July 23, 1983) is a political activist, whistle blower and computer hacker from Šibenik, Croatia. He founded the computer security website Jezgra.org in 1997. He was convicted and criminally charged in September 1999.Večernji list, September 17, 1999 "Sixteen-year-old hacker broke in to personal computer and network of Veselin Pejnović"Jutarnji list, September 18, 1999 "Hackers are thieves"Slobodna Dalmacija, September 18, 1999 "Break in program of Veselin Pejnović was accidental"Slobodna Dalmacija, September 19, 1999 "Šibenik hacker gets criminally charged" He was forbidden the use of any form of computer system or the internet for hacking the e-mail of politician Veselin Pejnović while planting a backdoor to his network. In 2005, he founded ŠI-WIFI Wireless, an organization that was formed for his town.Slobodna Dalmacija, May 23, 2014 "Šibenik city core covered by WIFI"Metro Express, March 15, 2007 (local) "They use WIFI to wirelessly network whole town of Šibenik"
Infrastructure in Šibenik Wireless network Periša was the founder and president of the ŠI-WIFI organization from 21 July 2005. In August 2010, Periša claimed that he blew the whistle on the Social Democratic Party (SDP) for overspending the local municipal budget on a wireless network."City gave money to their local Social Democratic Party member for nothing" Šibenski List, August 14, 2010 He informed the city mayor Mayor Ante Županović privately,Correspondence with city Mayor which Periša sent prior to building wireless network PDF who replied with little interest.Correspondence – city mayor replies to Denis Scanned letter Periša then publicly confronted Županović"Ante Županović – new city Mayor" T-portal, June 15, 2009 to accuse him of stealing public money."With 50.000kn I could network three towns, not just one" Slobodna Dalmacija, August 11, 2010
A local newspaper tested out the existing municipal wireless network in 2013 and concluded that Periša was right, and it was not working."City wireless is non-working" Novi Tjednik, September 25, 2013 After the Croatian Democratic Union (HDZ) took power, Periša was appointed to rebuild and maintain the city's wireless network, which he did using city funds in April 2014."Denis covers city core with wi-fi signal" Slobodna Dalmacija, May 22, 2014 The network was placed on 10 public nodes with 30 public antennas and access points."Mother of all networks" sibenskiportal.rtl.hr, April 27, 2014 (local) "City covered with wifi network" sibenskiportal.rtl.hr, May 23, 2014
On 20 November 2017, the ŠI-WIFI organization was closed and a new city network was established.official document
LoRaWAN In January 2019, Periša built and installed a new type of sensor network for Šibenik, using LoRaWAN technology, and based on an 868Mhz version. Šibenik was the first town in the region to use such a network."Sibenik just entered the future of the Internet" sibenik.in, March 17, 2019 "Sibensko Kninske Kronike 08" youtube.com, February 24, 2019"Sibenik and LoRaWAN future" sibenski.slobodnadalmacija.hr, March 03, 2019 (local)"Official The Things Network Sibenik Site" TTN Network, Jan, 2019
Activism Law and order Beginning in 2017, Periša worked on cases for local police and DORH (the state attorney) by coming across and prosecuting online bullies and people spreading hate with the possible use of physical violence towards others. He spoke about how to report such crimes on national television.HRT (Croatian National Television), about how to report hate speech HRT (national television), April 10, 2017Denis in Labirint on HRT about working with state attorney (available on demand) Labirint, HRT (national television) April 10, 2017"DarkMan files report on guy endorsing killing" Slobodna Dalmacija, March 30, 2017(local)Working with DORH 100posto.hr, March 29, 2017 Shortly after that, he was threatened and put under police protection."Day after reporting Denis ended up under police protection" prvi.hr March 30, 2017The following day, Periša needed and received police protection. republika.eu, March 30, 2017 Later on, he searched for fugitive Ivica Todorić and the servers Todorić used."In a few minutes I found the location of Todorić server" 100posto.hr, October 26, 2017
Anonymous group After a decade of claiming to lead hacking groups, Periša claims he finally joined the Anonymous group firstly fighting against ACTA and similar acts."Anonymous are modern Robin Hoods" sibenik.in, February 22, 2012 He encourages people to use the Linux OS for supposedly lower power consumption and better power savings."Savings: Denis advices switch to Linux" mok.hr, November 04, 2010 On June 4, 2015, Periša appeared on a Skype interview for the Alter EGO show talking about the internet and anonymously representing himself as one of the internet freedom fighters.Alter EGO 04.06.2015 Alter_EGO, June 04, 2015
COVID-19 pandemic During the COVID-19 pandemic, as part of a group, Periša made 3D-printed face shields for the local hospitals in Drniš and Knin."Denis plans to make face shields for the local hospital" sibenik.in, March 24, 2020 "Drniš hospital gets 3D-Printed face-shields donation" Radio Drniš, April 8, 2020"First 3D-Printed faceshields went to Murter" sibenik.in, March 26, 2020 "Denis plays his part in coronavirus outbreak" sibenik.in, March 24, 2020 "3D printers work day and night for hospitals" Slobodna Dalmacija, March 26, 2020"Computer experts and designers in fight against coronavirus" morski.hr, March, 2020
Public appearances In 2014, Periša began appearing at conferences, giving a guest lecture at the Split Film Festival (STFF) on the subject of "Hacking and (Privacy) Protection"."Denis Periša is giving lecture on hacking on Split Film Festival" sibenik.in, September 04, 2014 Organizer mentioning Denis Periša as a guest speaker of STFF in local newspaper Slobodna Dalmacija, September 13, 2014 He was interviewed about the same subject by H-Alter magazine with the subject "Table to table via smartphones", commenting on his previous work and the WikiLeaks arrests which had taken place shortly before that."Table to table via smartphones" H-Alter, September 19, 2014
In the summer of 2014, Periša was invited to do a video presentation on the island of Prvić on the subject of hacking and creative thinking."In search of lost communication" tris.com.hr, October 10, 2014
Periša conducted a live hack on the RTL television channel and did a demonstration of an MITM attack on 14 May 2019."DARKMAN shows how to hack mobile phone or some profile" RTL TELEVISION, May 14, 2019 "At 16 he hacked a politician and is now working for police" sibenik.in, May 14, 2019 "Croatian hacker showed how he can hack your mobile phone" POSLOVNI.hr, May 14, 2019
On 7 October 2019, Periša implanted an xNT NFC chip in his hand and discussed it on national television and other media."First Croatian Cyberfinger" Jutarnji.hr, Oct, 2019 (local)
In November 2019,"Udruga Zvonimir" Udruga Zvonimir, November 27, 2019. (local) Periša gave a live presentation and lecture on "Potrošači Digitalnog Doba" in Split, Croatia, on the subject of personal protection and Internet news, hacks and biohacking."Potrošači digitalnog doba conference" hup.hr, November 25, 2019"Famous hacker on lecture in Split" Slobodna Dalmacija, November 26, 2019"Central Consumers Portal Croatia" Središnji portal za potrošače, November 2019
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