(Yicai Global) Jan. 15 -- Fingerprint technology is becoming ever more popular in smartphones, but one Chinese executive claims the system is fundamentally flawed.

Li Yangyuan, chief technical officer of a Suzhou-based firm, demonstrated the issue to the Ministry of Industry and Information Technology, the Ministry of Public Security and the Cyberspace Administration of China on Jan. 12, Yangtse Evening Post, an affiliate of state-owned Xinhua News Agency, reported.

The report did not disclose Li's company, but several online sources name a Li Yangyuan as chairman and CTO of Mindray Microelectronics Co., which is based in Suzhou.

Li used a capacitive stylus to draw patterns on a piece of tape, which he then attached to a smartphone's fingerprint sensor, successfully unlocking it. He then used the tape to register a new fingerprint on the handset, and showed that even a piece of sponge could be used to unlock the phone.

Smartphone fingerprint sensors work by saving an image of a pre-registered fingerprint in a database. When a matching finger presses or touches the button, the phone will compare the new information with the registry and if they match, will unlock the phone. However, the boundaries for what constitutes a match appear to be insufficient.

"Contrary to what we assumed, mobile fingerprint recognition doesn't require 100 percent accuracy to pass the verification," Li said. "It probably only requires around 20 percent." He did not out any specific smartphone makers but said it should apply to most devices using fingerprint technology.