11. A computer-implemented authorization method performed at an authorization node executing an authorization policy, comprising: receiving, by a hardware processor, an assertion from a first entity comprising a credential statement, wherein the first entity consents to import a fact from a further entity; and using the authorization policy, the authorization policy being a SecPAL policy, to evaluate the assertion, the assertion being validated in the case that each of the following are met: i) the first entity consents to import the fact from the further entity, consent comprising a SecPAL “can say” statement; ii) the further entity consents to export the fact to the first entity, consent comprising a SecPAL “can listen to” statement; and iii) the further entity asserts the fact.
11. A computer-implemented authorization method performed at an authorization node executing an authorization policy, comprising: receiving, by a hardware processor, an assertion from a first entity comprising a credential statement, wherein the first entity consents to import a fact from a further entity; and using the authorization policy, the authorization policy being a SecPAL policy, to evaluate the assertion, the assertion being validated in the case that each of the following are met: i) the first entity consents to import the fact from the further entity, consent comprising a SecPAL “can say” statement; ii) the further entity consents to export the fact to the first entity, consent comprising a SecPAL “can listen to” statement; and iii) the further entity asserts the fact. 12. A method according to claim 11 , further comprising the step of, subsequent to receiving the assertion, detecting the credential statement delegating authority and automatically inserting condition ii) into the statement delegating authority.