Specifying security protocols and policy constraints in distributed systems
First Claim
Patent Images
1. A method for system security in distributed systems, said method comprising the steps of:
- a) making authentic statements by trusted intermediaries;
b) deriving freshness constraints from initial policy assumptions and the authentic statements; and
c) imposing freshness constraints by employing recent-secure authenticating principals to effect revocation;
wherein said step b) comprises the substep I) of normalizing suffix constraints of the freshness constraint prior to applying other rules; and
wherein said substep I) comprises applying the following axiom, (A→
B notbefore t1 notafter t2)⊃
(((t1≦
t3)Λ
(t4≦
t2))⊃
A→
B notbefore t3 notafter t4).
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Abstract
A recent secure authentication service enforcing revocation in distributed systems is provided. Authenticity entities impose freshness constraints, derived from initial policy assumptions and authentic statements made by trusted intermediaries, in authenticated statements made by intermediaries. If freshness constraints are not presented, authentication is questionable. The freshness constraints can be adjusted. The delay for revocation can be arbitrarily bounded. The freshness constraints within certificates results in a secure and highly available revocation service such that less trust is required of the service.
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Citations
46 Claims
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1. A method for system security in distributed systems, said method comprising the steps of:
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a) making authentic statements by trusted intermediaries;
b) deriving freshness constraints from initial policy assumptions and the authentic statements; and
c) imposing freshness constraints by employing recent-secure authenticating principals to effect revocation;
wherein said step b) comprises the substep I) of normalizing suffix constraints of the freshness constraint prior to applying other rules; and
wherein said substep I) comprises applying the following axiom, (A→
B notbefore t1 notafter t2)⊃
(((t1≦
t3)Λ
(t4≦
t2))⊃
A→
B notbefore t3 notafter t4).
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2. A method for system security in distributed systems, said method comprising the steps of:
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a) making authentic statements by trusted intermediaries;
b) deriving freshness constraints from initial policy assumptions and the authentic statements; and
c) imposing freshness constraints by employing recent-secure authenticating principals to effect revocation;
wherein said step c) comprises specifying the time of revocation;
wherein said step c) includes trusting principals not to lie when specifying the time of revocation certificates;
wherein said step c) further comprises the substep I) of arbitrarily bounding certain revocation by adjusting the freshness constraints;
wherein said substep I) comprises applying the following axioms, (A→
B notbefore t1 notafter t2)⊃
(((A says s at t3)(t1≦
tnow, t3≦
t2))⊃
(B says s at t3)); and
(A says (B→
A notbefore t1 notafter t2) at t3)⊃
(B→
A notbefore t1 notafter t2).
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3. A method for enforcing revocation in distributed systems, said method comprising the steps of:
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a) issuing one or more initial assertions by one or more distinguished principals;
b) asserting, by the distinguished principals, one or more principals with authority for asserting a time stamped validity assertion pertaining to the validity of each initial assertion;
c) asserting the time stamped validity assertion to none or more initial assertions indicating their validity at the time of the time stamp;
d) asserting freshness constraints indicating a length of time and the initial assertions that the freshness constraints relate; and
f) verifying that a relation |tnow−
ttime stamp|≦
δ
is satisfied for each particular assertion necessary for verification of a secure channel, where ttime stamp is a time of a time stamp pertaining to the validity assertion of a particular assertion, δ
being a minimum necessary freshness constraint pertaining to the particular assertion and tnow being the time of verification.- View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
g) distributing the time stamped certificates to storage systems and communication networks.
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18. A method according to claim 17, wherein said step g) includes addressing the distribution of the time stamped certificates to one or more multicast addresses.
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19. A method according to claim 17, wherein in said step t) distribution occurs at periodic intervals.
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20. A method according to claim 3 wherein said step d) includes asserting the freshness constraints within the initial assertions.
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21. A method according to claim 3, wherein said step d) includes asserting the freshness constraints by a risk taker.
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22. A method according to claim 21, wherein the risk taker is a verifier.
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23. A method according to claim 3, wherein in said step d) includes cryptographically certifying the freshness constraint and the initial assertions using a signing key.
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24. A method according to claim 3, wherein said step d) comprises the substep of storing the freshness constraints and the initial assertions in trusted storage systems trusted by other entities as being an assertion of the principals making the assertion.
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25. A method according to claim 3, wherein said step f) includes dynamically changing the time of verification.
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26. A method according to claim 23, wherein said step d) further comprises including an assertion on behalf of a parent distinguished principal due to the delegated authority obtained by said steps a)-c), and wherein said step e) further comprises making a freshness constraint in assertions made by a child distinguished principal in said steps a)-d) more restrictive than freshness constraints made by the parent distinguished principal.
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27. A method for protecting an authority of one or more distinguished principals and enforcing revocation when the authority is compromised, said method comprising the steps of:
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a) issuing one or more initial assertions delegating authority by a first one of the distinguished principals to a second one of the distinguished principals;
b) issuing one or more secondary assertions delegating authority by the second one of the distinguished principals to a third one of the distinguished principals;
c) repeating said step b) none or more times;
d) issuing one or more authoritative assertions by one or more of the distinguished principals;
e) asserting freshness constraints on assertions;
f) asserting a time stamped validity assertion to the assertions in said steps a)-e) indicating the validity of the assertions in said steps a)-e) at the time of the time stamp;
g) verifying that a relation |tnow−
ttime stamp|≦
δ
is satisfied for each particular assertion necessary for verification of a secure channel, where ttime stamp being the time of a time stamp pertaining to the validity assertion of the particular assertion, δ
being the minimum necessary freshness constraint pertaining to the particular assertion, and tnow being the time of verification.- View Dependent Claims (28, 29, 30, 31)
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32. A method for issuing certificates in a system for enforcing revocation in distributed systems, said method comprising the steps of:
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a) designating a policy authority for dictating policy to subordinates;
b) asserting an organization subject to a policy of a policy authority;
c) issuing certificates for subordinate principals within the organization by the organization;
d) asserting, by the organization, a principal authorized as an authority for issuing time stamped certificates;
e) delegating authority for issuing time stamped certificates;
f) asserting freshness constraints on assertions; and
g) verifying that a relation |tnow−
ttime stamp|≦
δ
is satisfied for each particular assertion necessary for verification of a secure channel, where ttime stamp being a time of a time stamp pertaining to the validity assertion of a particular assertion, δ
being a minimum necessary freshness constraint pertaining to the particular assertion and tnow being the time of verification.- View Dependent Claims (33, 34, 35, 36, 37)
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38. A method for system security in a distributed system network, comprising the steps of:
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a) receiving a policy in the distributed system network;
b) preparing an initial statement in the distributed system network in response to said policy;
c) preparing a second statement of an assigned revocation authority in the distributed system network in response to said policy, said second statement being associated with said initial statement;
d) preparing a third statement of a freshness constraint period in the distributed system network in response to said policy, said third statement being associated with said initial statement;
e) preparing a validity statement at said assigned revocation authority in the distributed system network in response to said policy, said validity statement including a verification status at some temporal reference;
f) providing said initial statement, said second statement, said third statement, and said validity statement to a verification authority in the distributed system network; and
g) selectively verifying said initial statement at said verification authority in response to said initial statement, said second statement, said third statement, and said validity statement. - View Dependent Claims (39, 40, 41)
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42. A method for system security in a distributed system network, comprising the steps of:
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a) receiving a first term policy in the distributed system network;
b) preparing an initial statement in the distributed system network in response to said first term policy;
c) preparing a second statement of an assigned revocation authority pointer in the distributed system network in response to said first term policy, said second statement being associated with said initial statement;
d) preparing a third statement delegating a freshness constraint period to said assigned revocation authority pointer in the distributed system network in response to said first term policy;
e) providing a medium term policy to said revocation authority pointer in the distributed system network;
f) preparing a fourth statement of medium term delegation at said revocation authority pointer in response to said medium term policy, said medium term delegation naming an assigned revocation authority;
g) preparing a fifth statement of a particular freshness constraint period at said revocation authority pointer in response to said medium term policy;
h) providing a third term policy to said revocation authority in the distributed system network;
I) preparing a validity statement at said assigned revocation authority in the distributed system network in response to said third term policy, said validity statement including a verification status at some temporal reference;
j) providing said initial statement, said second, third, fourth, and fifth statements, and said validity statement to a verification authority in the distributed system network; and
k) selectively verifying said initial statement at said verification authority in response to said initial statement, said second, third, fourth, and fifth statements, and said validity statement. - View Dependent Claims (43, 44, 45, 46)
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Specification