Denis Periša

Early Life and Introduction to Hacking

Denis Periša was born on July 23, 1983, in Šibenik, Croatia. At the age of fourteen, he founded Jezgra.org, a computer security website, in 1997. In September 1999, he was criminally convicted and charged for hacking the email account of politician Veselin Pejnović and planting a backdoor on his network. As a result of the conviction, Periša was forbidden from using any form of computer system or the internet.

Civic Infrastructure Work

Wireless Network

In 2005, Periša founded ŠI-WIFI, a wireless network organization established to serve his hometown of Šibenik. He served as founder and president of the organization from July 21, 2005. In August 2010, Periša publicly accused the Social Democratic Party (SDP) of overspending the local municipal budget on a wireless network project. After initially raising the matter privately with Mayor Ante Županović and receiving little response, Periša publicly confronted the mayor, accusing him of misappropriating public funds.

A local newspaper tested the municipal wireless network in 2013 and concluded that Periša's claims were accurate — the network was not functioning. Following a change in local government, with the Croatian Democratic Union (HDZ) taking power, Periša was appointed to rebuild and maintain the city's wireless network. In April 2014, using city funds, he oversaw the deployment of a network spanning 10 public nodes with 30 public antennas and access points. The ŠI-WIFI organization was formally closed on November 20, 2017, when a new city network was established.

LoRaWAN Sensor Network

In January 2019, Periša built and installed a LoRaWAN sensor network for Šibenik, operating on an 868 MHz frequency. Šibenik was reported to be the first town in the region to adopt such a network.

Activism

Law and Order

Beginning in 2017, Periša worked alongside local police and DORH, the Croatian state attorney's office, identifying and helping prosecute individuals engaged in online harassment and hate speech with potential for physical violence. He discussed methods for reporting such crimes on national television. Following this public activity, Periša received threats and was placed under police protection. He also conducted searches related to fugitive Ivica Todorić and the servers Todorić had used.

Anonymous and Internet Freedom

Periša has claimed affiliation with the Anonymous collective, stating he joined the group in part to oppose legislation such as ACTA. He advocates for the use of the Linux operating system, citing lower power consumption as a benefit. On June 4, 2015, he appeared in a Skype interview on the Alter EGO show, discussing internet freedom while representing himself anonymously.

COVID-19 Response

During the COVID-19 pandemic, Periša participated in a group effort to 3D-print face shields for local hospitals in Drniš and Knin.

Public Appearances

From 2014 onward, Periša became an active presence at public events and conferences. He delivered a guest lecture at the Split Film Festival (STFF) on the subject of hacking and privacy protection, and was interviewed by H-Alter magazine on related topics, including commentary on WikiLeaks-related arrests. In the summer of 2014, he was invited to give a video presentation on the island of Prvić covering hacking and creative thinking.

On May 14, 2019, Periša conducted a live demonstration of a man-in-the-middle (MITM) attack on the RTL television channel. On October 7, 2019, he had an xNT NFC chip implanted in his hand and discussed the procedure on national television and in other media. In November 2019, he delivered a live lecture in Split titled "Potrošači Digitalnog Doba" (Consumers of the Digital Age), covering personal protection, internet news, hacking, and biohacking.