Method and apparatus for providing an adaptable security level in an electronic communication

1. A method of communicating between a first correspondent and a second correspondent in a data communication system, the method performed on a frame-by-frame basis and comprising:

assembling a data stream at said first correspondent, said data stream having at least one frame, said frame having a header and data;

determining a security level for a frame type of said frame based on a policy, wherein the policy identifies a minimum security level for the frame type;

incorporating in said header, an indication of said frame type and an indication of said security level;

forwarding said frame to said second correspondent to enable said second correspondent to determine the acceptability of said frame according to said frame type;

receiving, from said second correspondent, a frame including security bits that identify a security level for said received frame;

determining a minimum security level based on a frame type of said received frame and the policy;

if said security level for said received frame meets said minimum security level for said received frame, accept said received frame; and

if said security level for said received frame does no meet the minimum security level for said received frame, reject said received frame.

2. The method according to claim 1 further comprising said second correspondent:

receiving said frame;

determining said frame type from said header; and

correlating said frame type to said policy to determine if said frame type is acceptable for at least one attribute of said frame.

3. The method according to claim 2 further comprising accepting said frame is said policy is met, and rejecting said frame otherwise.

4. The method according to claim 2 wherein said header includes a representation of a key and said policy indicates an acceptable frame type for said key.

5. The method according to claim 2 wherein said header includes an indication of a security level and said policy indicates an acceptable frame type for said security level.

6. The method according to claim 2 wherein said policy indicates frame types vulnerable to an attack where one or more combinations of security features of said frame are present, said method comprising rejecting said frame if one of said combinations is found.

7. The method according to claim 2 wherein said frame includes one or more security bits indicative of a security level, and said method comprises said second correspondent extracting said security bits to determine said security level wherein said policy indicates whether or not said frame type is acceptable for said security level.

8. The method according to claim 2 wherein said policy comprises a look up table correlating said frame type to said at least one attribute.

9. The method according to claim 1 comprising anyone or both of encrypting said data and signing said data according to said security level.

10. The method according to claim 1 wherein said security level is a minimum acceptable security level and said minimum acceptable security level is independent of said data.

11. The method according to claim 1 wherein said security level is a minimum acceptable security level and said minimum acceptable security level is dependent on said data.

12. The method according to claim 11 wherein said data is anyone or both of encrypted and signed, said method comprising said second correspondent decrypting said data and/or authenticating said data according to said security bits.

13. The method according to claim 1 wherein said security level is a minimum acceptable security level and said minimum acceptable security level is partially data dependent such that said minimum acceptable security level differs according to said frame type.

14. The method according to claim 1 wherein said frame further comprises a footer comprising one or more bits representing an error code.

15. The method according to claim 1 wherein said header comprises a key identifier, a representation of a key corresponding to said key identifier, a security level, and an originator for determining the acceptability of said frame type.

16. A method of verifying a communication on a frame-by-frame basis between a first correspondent and a second correspondent in a data communication system comprising said second correspondent:

receiving from said first correspondent, a frame having a header and data, said header including an indication of a frame type and an indication of a security level for the frame;

determining said frame type from said header; and

determining a minimum security level for said frame type based on a policy;

if said security level meets said minimum security level for said frame, accept said frame; and

if said security level for said frame does not meet the minimum security level for said frame, reject said frame.

17. The method according to claim 16 further comprising accepting said frame is said policy is met, and rejecting said frame otherwise.

18. The method according to claim 16 wherein said header includes a representation of a key and said policy indicates an acceptable frame type for said key.