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I am working on Ciphertext-Policy Attribute based Encryption (CP-ABE) and I need to understand how a secret key looks like.

For example, assume that the universe of attributes is defined to be {A,B,C,D} and user 1 receives a secret key (SK) to attributes {A,B} such that: A="NY" and B="Computer". My question is: Does SK have a certain structure or is it a bit-string? More specifically: - Does it leak the name of attributes the user have (in this case A and B)? - Does it leak information about "NY" and "Computer"? - If I generate another secret key for attributes A, B and C, can I distinguish between the two secret keys by just looking at them?

Dukefleed
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  • Are you talking about a specific implementation of CP-ABE? Generally the secret key contains the name of the attribute and its corresponding value in a retrievable format. Regarding your last question, yes because of the above. – Artjom B. Nov 20 '14 at 17:07
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    Keep in mind that you generally cannot determine who is the owner of those keys, because they may have been delegated and re-randomized, if that is what you're after. You would need some kind of traceability for that. – Artjom B. Nov 20 '14 at 17:10
  • The attribute owner knows his attributes but doesn't know the attributes of other users. Furthermore, in ABE any secret key for an attribute is especial for one user. In other words, the amount of secret key for two users that have attribute "A" isn't equal. – Mahdi Mahdavi Dec 01 '20 at 18:54

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