Method of accessing a shared subroutine of computer system

Method of accessing a shared subroutine (4a, 4b, 4c) being part of a shared library (4) of a computer system (100), characterized by the following steps:

• generating (40) a first security information in an authorized application (1, 3),
• calling said shared subroutine (4a, 4b, 4c) and passing said first security information to said shared subroutine (4a, 4b, 4c),
• executing (60) said shared subroutine (4a, 4b, 4c) by
• generating (62) a second security information in said shared subroutine (4i a, 4b, 4c),
• comparing (64) said first security information to said second security information,
• deriving (66) a security level from the result of the comparison (64)
• processing (68) said shared subroutine in a mode that depends on said security level.

Computer system (100) comprising at least one shared subroutine (4a, 4b, 4c), characterized by being capable of performing the method of:

• encrypting (10) an original parameter list to obtain an encrypted parameter list,
• calling (20) said shared subroutine (4a, 4b, 4c) with said encrypted parameter list,
• executing (30) said shared subroutine (4a, 4b, 4c) by
• decrypting (31) said encrypted parameter list in said shared subroutine (4a, 4b, 4c) to obtain a decrypted parameter list corresponding to said original parameter list, and by
• processing (32) said decrypted parameter list.

Computer system (100) comprising at least one shared subroutine (4a, 4b, 4c), characterized by being capable of performing the method of:

• generating (40) a first security information in an authorized application (1, 3),
• calling said shared subroutine (4a, 4b, 4c) and passing said first security information to said shared subroutine (4a, 4b, 4c),
• executing (60) said shared subroutine (4a, 4b, 4c) by
• generating (62) a second security information in said shared subroutine (4a, 4b, 4c),
• comparing (64) said first security information to said second security information,
• deriving (66) a security level from the result of the comparison (64)
• processing (68) said shared subroutine in a mode that depends on said security level.

Computer program product on a computer usable medium having computer readable program code means comprising at least one shared subroutine (4a, 4b, 4c) and at least one application (1), characterized by being capable of performing:

• encrypting (10) an original parameter list to obtain an encrypted parameter list,
• calling (20) said shared subroutine (4a, 4b, 4c) with said encrypted parameter list,
• executing (30) said shared subroutine (4a, 4b, 4c) by
• decrypting (31) said encrypted parameter list in said shared subroutine (4a, 4b, 4c) to obtain a decrypted parameter list corresponding to said original parameter list, and by
• processing (32) said decrypted parameter list.

Computer program product on a computer usable medium having computer readable program code means comprising at least one shared subroutine (4a, 4b, 4c) and at least one application (1), characterized by being capable of performing:

• generating (40) a first security information in an authorized application (1, 3),
• calling said shared subroutine (4a, 4b, 4c) and passing said first security information to said shared subroutine (4a, 4b, 4c),
• executing (60) said shared subroutine (4a, 4b, 4c) by
• generating (62) a second security information in said shared subroutine (4a, 4b, 4c),
• comparing (64) said first security information to said second security information,
• deriving (66) a security level from the result of the comparison (64)
• processing (68) said shared subroutine in a mode that depends on said security level.