Patent ID: 8340301

Claim:
Method for establishing a secret key between two nodes in a communication network, in particular in a wireless local area network (WLAN), comprising: first node (B) broadcasting one or more packets (P i ) that can be received by second node (A), wherein the packets (P i ) contain each a first key (K i ) and wherein the packets (P i ) are each encrypted with a second key (k i ) before being sent, the second node (A) randomly choosing one packet (P m ) from the packets (P i ) received and breaks the encryption of the chosen packet (P m ) in order to obtain the first key (K m ), and the second node (A) initiating a key exchange protocol, wherein the second node (A) encrypts the message to be sent for initiating the key exchange protocol with the revealed first key (K m ), wherein the encryption of the packets (P i ) with the second (k i ) is an encryption that is broken by a brute force attack comprising a multiplicity of decryption attempts, and wherein the second node (A) breaks the encryption of the chosen packet (P m ) in order to obtain the first key (K m ) without having the second key (k i ).