Patent ID: 7134024

Claim:
Method of establishing a trustworthiness level (TL) of a participant ( 2 ) in a communication connection between a first communication partner ( 1 ) and a second communication partner ( 3 ) and for adapting communication behaviour to the established trustworthiness level (TL), whereby said participant ( 2 ) is equipped with a trustworthiness certificate ( 6 ) and a therefrom separated securely stored participant private key ( 8 ) and that said first communication partner ( 1 ) receives said trustworthiness certificate ( 6 ) from said participant ( 2 ), wherefrom said trustworthiness level (TL) is derived and established and said first communication partner ( 1 ) tests whether said trustworthiness certificate ( 6 ) belongs to said participant ( 2 ) using said participant private key ( 8 ) and that in case said trustworthiness certificate ( 6 ) is confirmed by said test to belong to said participant ( 2 ), said first communication partner ( 1 ) communicates said established trustworthiness level (TL) to said second communication partner ( 3 ) and that at least one parameter of said communication behaviour is chosen in dependence of said established trustworthiness level (TL), characterized in that the first communication partner ( 1 ) communicates the established trustworthiness level (TL) to the second communication partner ( 2 ) by piggybacking a trustworthiness level information (TLT) onto a communication message, signing said communication message with a first-partner private key ( 13 ) and sending it to said second communication partner ( 3 ).