Patent ID: 8001378

Claim:
A method for protecting data of a mobile agent (MA) from a first server(A) which are intended for at least one second server(B) within a network system against an attack and an unauthorized access, wherein the first server(A) as well as the at least one second server (B) have a pair of a public key (KA, KB) and a private key (PKA, PKB) associated therewith, respectively, the method comprising: choosing a unique number (r0) and assigning it to the mobile agent (MA); choosing a secret symmetric key (SKo) and assigning it to data (mB) to be protected; encoding the secret key (SKo) with the public key (KB) of the second server (B); encrypting the secret key (SKo) and the public key (KA) of the first server via a wrapping function (h), thus forming a data authentication code (h(KA, SKo)); encoding the data (mB) with the secret key (SKo); combining the unique number (r0), the encoded data ({mB}SKo), the encoded secret key({SKo}KB) and the data authentication code (h(KA, SKo)); and encoding that combination with the private key (PKA) of the first server (A) to form a nested structure to be decoded successively for access to the data (mB).