German software engineer Karsten Nohl said at the Chaos Communication Congress hacker expo today that he and a group have cracked and published the primary encryption code for GSM, the protocol that handles most non-3G cellphone calls. The team says it has used legal methods to break the A5/1 standard, which prevents easy snooping, and has made available a 'code book' of binary data that could theoretically be used to decipher the content of a call within hours or even minutes rather than weeks.
