51 lines
2.0 KiB
Rust
51 lines
2.0 KiB
Rust
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/*! A module for the protocol for the user to get promoted from
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untrusted (trust level 0) to trusted (trust level 1).
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They are allowed to do this as long as UNTRUSTED_INTERVAL days have
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passed since they obtained their level 0 Lox credential, and their
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bridge (level 0 users get put in a one-bridge bucket) has not been
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blocked. (Blocked bridges in one-bridge buckets will have their entries
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removed from the bridge authority's migration table.)
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The user presents their current Lox credential:
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- id: revealed
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- bucket: blinded
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- trust_level: revealed to be 0
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- level_since: blinded, but proved in ZK that it's at least
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UNTRUSTED_INTERVAL days ago
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- invites_remaining: revealed to be 0
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- invites_issued: revealed to be 0
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They will receive in return the encrypted MAC (Pk, EncQk) for their
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implicit Migration Key credential with attributes id and bucket,
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along with a HashMap of encrypted Migration credentials. For each
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(from_i, to_i) in the BA's migration list, there will be an entry in
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the HashMap with key H1(id, from_attr_i, Qk_i) and value
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Enc_{H2(id, from_attr_i, Qk_i)}(to_attr_i, P_i, Q_i). Here H1 and H2
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are the first 16 bytes and the second 16 bytes respectively of the
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SHA256 hash of the input, P_i and Q_i are a MAC on the Migration
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credential with attributes id, from_attr_i, and to_attr_i. Qk_i is the
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value EncQk would decrypt to if bucket were equal to from_attr_i. */
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use curve25519_dalek::ristretto::RistrettoBasepointTable;
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use curve25519_dalek::ristretto::RistrettoPoint;
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use curve25519_dalek::scalar::Scalar;
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use curve25519_dalek::traits::IsIdentity;
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use zkp::CompactProof;
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use zkp::ProofError;
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use zkp::Transcript;
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/// The minimum number of days a user has to be at trust level 0
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/// (untrusted) with their (single) bridge unblocked before they can
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/// move to level 1.
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///
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/// The implementation also puts an upper bound of UNTRUSTED_INTERVAL +
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/// 511 days, which is not unreasonable; we want users to be engaging
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/// with the system in order to move up trust levels.
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pub const UNTRUSTED_INTERVAL: u64 = 30;
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pub struct Request {
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id: Scalar,
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}
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