US 2003/0190043 A1 · Protection of software against use without permit

Abstract

An arrangement to protect software, particularly freely distributed application software, against utilization without permission of the copyright holder. By encrypting the software employing a key (k1) which is different from that key (k2) which is employed in the decryption, better protection is obtained against unauthorized utilization when the decryption key is kept secret to the user. Further improved security is achieved by additionally executing scrambling-descrambling of the communication between the computer in which the software is utilized and the external unit in which the decryption key is stored. Also, the external unit is arranged such that it returns to the host computer, the result from its processing of data received from the host, the result then being utilized in the further execution of the respective program.

Claims27

Dependent claims

A method of preventing unauthorized utilization of software in a computer, the method comprising the steps of:

encrypting at least a part of said software in accordance with a first algorithm, and
decrypting the encrypted part of the software in accordance with a second algorithm, the second algorithm together with a key to be employed in the decryption of the encrypted part of the software being stored in an external unit adapted to be connected to said computer, the external unit comprising at least a computer readable storage medium and a processor of its own,
characterized in that said decryption in accordance with the second algorithm (g2) is executed by employing a second key (k2) stored in said external unit, the second key being different from a first key (k1) employed in the execution of the encryption of said part of the software in accordance with the first algorithm (g1).

A method of preparing software, particularly software intended for free distribution, for the utilization in a computer only with a corresponding authorization, the method comprising encrypting in accordance with a first algorithm at least a part of said software which by the utilization in said computer is decrypted in accordance with a second algorithm,

characterized in that a key which is employed for said encryption in accordance with the first algorithm (g1), is a first key (k1) which is different from a second key (k2) which is employed in the execution of the decryption in accordance with the second algorithm (g2) of that part of the software which is encrypted in accordance with the first algorithm and first key.

A device for the preparation of software, particularly software intended for free distribution, to be utilized in a computer only with a corresponding authorization, the device comprising:

crypto means effecting the encryption of at least a part of said software in accordance with a first algorithm and a first key, and
an external unit adapted to be connected to said computer, the external unit at least comprising a processor of its own and a computer readable storage medium for storing a second algorithm and a key, and being disposed to execute decryption of the encrypted part of the software in accordance with said second algorithm and key,
characterized in that the device further comprises generator means to provide said second algorithm (g2) and a second key (k2) intended to be employed in said decryption in accordance with the second algorithm (g2), the second key being different from the first key (k1) employed by said crypto means in the execution of the encryption of said part of the software in accordance with the first algorithm (g1).

Dependencies are inferred from the claim text.

Protection of software against use without permit

Life of this patent

Protection of software against use without permit

Life of this patent

Abstract

Claims27