“Are your phone conversations about to become less secure? A German encryption expert says he’s cracked the two-decade-old algorithm that protects most of the world’s cellphones: GSM (Global System for Mobile communication). Karsten Nohl says his intentions were noble; he wanted to show the world that though GSM protects 80 percent of the cellphones in the world, it’s far from invincible. ‘This shows that existing G.S.M. security is inadequate,’ Mr. Nohl, 28, told about 600 people attending the Chaos Communication Congress, a four-day conference of computer hackers that runs through Wednesday in Berlin. ‘We are trying to push operators to adopt better security measures for mobile phone calls.’ Nohl and a team of others had been working independently since August to hack the code. Developed in 1988, the system prevents the interception of calls by forcing phones and base stations to change frequencies constantly.”