The complete blockage migration protocol
This commit is contained in:
Ian Goldberg
parent
4bb77d16e4
commit
596cf10ea5
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@ -536,6 +536,7 @@ pub fn pt_dbl(P: &RistrettoPoint) -> RistrettoPoint {
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/// Response. It also adds a handle_* function to the BridgeAuth struct
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/// that consumes a Request and produces a Result<Response, ProofError>.
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pub mod proto {
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pub mod blockage_migration;
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pub mod check_blockage;
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pub mod issue_invite;
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pub mod level_up;
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@ -0,0 +1,682 @@
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/*! A module for the protocol for the user of trust level 3 or higher to
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migrate from one bucket to another because their current bucket has been
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blocked. Their trust level will go down by 2.
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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 3 or higher
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- level_since: blinded
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- invites_remaining: blinded
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- blockages: blinded
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and a Migration credential:
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- id: revealed as the same as the Lox credential id above
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- from_bucket: blinded, but proved in ZK that it's the same as the
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bucket in the Lox credential above
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- to_bucket: blinded
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and a new Lox credential to be issued:
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- id: jointly chosen by the user and BA
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- bucket: blinded, but proved in ZK that it's the same as the to_bucket
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in the Migration credential above
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- trust_level: revealed to be 2 less than the trust_level above
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- level_since: today
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- invites_remaining: revealed to be LEVEL_INVITATIONS for the new trust
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level [Actually, there's a bug in the zkp crate that's triggered when
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a public value is 0 (the identity element of the Ristretto group), so
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we treat this field as blinded, but the _server_ encrypts the value.]
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- blockages: blinded, but proved in ZK that it's one more than the
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blockages above
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*/
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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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use super::super::cred;
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use super::super::dup_filter::SeenType;
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use super::super::migration_table::MigrationType;
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use super::super::scalar_u32;
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use super::super::{BridgeAuth, IssuerPubKey};
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use super::super::{CMZ_A, CMZ_A_TABLE, CMZ_B, CMZ_B_TABLE};
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use super::check_blockage::MIN_TRUST_LEVEL;
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use super::level_up::LEVEL_INVITATIONS;
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pub struct Request {
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// Fields for blind showing the Lox credential
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P_lox: RistrettoPoint,
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id: Scalar,
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CBucket: RistrettoPoint,
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trust_level: Scalar,
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CSince: RistrettoPoint,
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CInvRemain: RistrettoPoint,
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CBlockages: RistrettoPoint,
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CQ_lox: RistrettoPoint,
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// Fields for blind showing the Migration credential
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P_mig: RistrettoPoint,
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CFromBucket: RistrettoPoint,
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CToBucket: RistrettoPoint,
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CQ_mig: RistrettoPoint,
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// Fields for user blinding of the Lox credential to be issued
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D: RistrettoPoint,
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EncIdClient: (RistrettoPoint, RistrettoPoint),
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EncBucket: (RistrettoPoint, RistrettoPoint),
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EncBlockages: (RistrettoPoint, RistrettoPoint),
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// The combined ZKP
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piUser: CompactProof,
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}
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#[derive(Debug)]
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pub struct State {
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d: Scalar,
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D: RistrettoPoint,
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EncIdClient: (RistrettoPoint, RistrettoPoint),
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EncBucket: (RistrettoPoint, RistrettoPoint),
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EncBlockages: (RistrettoPoint, RistrettoPoint),
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id_client: Scalar,
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to_bucket: Scalar,
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trust_level: Scalar,
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blockages: Scalar,
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}
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pub struct Response {
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// The new attributes; the trust_level and invites_remaining are
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// implicit
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level_since: Scalar,
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// The fields for the new Lox credential
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P: RistrettoPoint,
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EncQ: (RistrettoPoint, RistrettoPoint),
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EncInvRemain: (RistrettoPoint, RistrettoPoint),
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id_server: Scalar,
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TId: RistrettoPoint,
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TBucket: RistrettoPoint,
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TInvRemain: RistrettoPoint,
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TBlockages: RistrettoPoint,
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// The ZKP
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piBlindIssue: CompactProof,
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}
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define_proof! {
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requestproof,
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"Blockage Migration Request",
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(bucket, since, invremain, blockages, zbucket, zsince, zinvremain,
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zblockages, negzQ_lox,
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tobucket, zfrombucket, ztobucket, negzQ_mig,
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d, eid_client, ebucket, eblockages, id_client),
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(P_lox, CBucket, CSince, CInvRemain, CBlockages, V_lox, Xbucket,
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Xsince, Xinvremain, Xblockages,
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P_mig, CFromBucket, CToBucket, V_mig, Xfrombucket, Xtobucket,
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D, EncIdClient0, EncIdClient1, EncBucket0, EncBucket1,
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EncBlockages0, EncBlockages1_minus_B),
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(A, B):
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// Blind showing of the Lox credential
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CBucket = (bucket*P_lox + zbucket*A),
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CSince = (since*P_lox + zsince*A),
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CInvRemain = (invremain*P_lox + zinvremain*A),
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CBlockages = (blockages*P_lox + zblockages*A),
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V_lox = (zbucket*Xbucket + zsince*Xsince + zinvremain*Xinvremain
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+ zblockages*Xblockages + negzQ_lox*A),
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// Blind showing of the Migration credential; note the use of the
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// same "bucket" secret variable
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CFromBucket = (bucket*P_mig + zfrombucket*A),
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CToBucket = (tobucket*P_mig + ztobucket*A),
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V_mig = (zfrombucket*Xfrombucket + ztobucket*Xtobucket + negzQ_mig*A),
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// User blinding of the Lox credential to be issued; note the use of
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// the same "tobucket" secret variable
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D = (d*B),
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EncIdClient0 = (eid_client*B),
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EncIdClient1 = (id_client*B + eid_client*D),
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EncBucket0 = (ebucket*B),
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EncBucket1 = (tobucket*B + ebucket*D),
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EncBlockages0 = (eblockages*B),
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EncBlockages1_minus_B = (blockages*B + eblockages*D)
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}
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define_proof! {
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blindissue,
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"Blockage Migration Blind Issuing",
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(x0, x0tilde, xid, xbucket, xlevel, xsince, xinvremain, xblockages,
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s, b, tid, tbucket, tinvremain, tblockages),
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(P, EncQ0, EncQ1, X0, Xid, Xbucket, Xlevel, Xsince, Xinvremain,
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Xblockages, Plevel, Psince, TId, TBucket, TInvRemain, TBlockages,
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D, EncId0, EncId1, EncBucket0, EncBucket1, EncInvRemain0,
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EncInvRemain1, EncBlockages0, EncBlockages1),
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(A, B):
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Xid = (xid*A),
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Xlevel = (xlevel*A),
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Xbucket = (xbucket*A),
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Xsince = (xsince*A),
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Xinvremain = (xinvremain*A),
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Xblockages = (xblockages*A),
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X0 = (x0*B + x0tilde*A),
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P = (b*B),
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TId = (b*Xid),
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TId = (tid*A),
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TBucket = (b*Xbucket),
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TBucket = (tbucket*A),
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TInvRemain = (b*Xinvremain),
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TInvRemain = (tinvremain*A),
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TBlockages = (b*Xblockages),
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TBlockages = (tblockages*A),
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EncQ0 = (s*B + tid*EncId0 + tbucket*EncBucket0
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+ tinvremain*EncInvRemain0 + tblockages*EncBlockages0),
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EncQ1 = (s*D + tid*EncId1 + tbucket*EncBucket1
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+ tinvremain*EncInvRemain1 + tblockages*EncBlockages1
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+ x0*P + xlevel*Plevel + xsince*Psince)
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}
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pub fn request(
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lox_cred: &cred::Lox,
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migration_cred: &cred::Migration,
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lox_pub: &IssuerPubKey,
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migration_pub: &IssuerPubKey,
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) -> Result<(Request, State), ProofError> {
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let A: &RistrettoPoint = &CMZ_A;
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let B: &RistrettoPoint = &CMZ_B;
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let Atable: &RistrettoBasepointTable = &CMZ_A_TABLE;
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let Btable: &RistrettoBasepointTable = &CMZ_B_TABLE;
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// Ensure that the credenials can be correctly shown; that is, the
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// ids match and the Lox credential bucket matches the Migration
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// credential from_bucket
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if lox_cred.id != migration_cred.lox_id || lox_cred.bucket != migration_cred.from_bucket {
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return Err(ProofError::VerificationFailure);
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}
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// The trust level must be at least MIN_TRUST_LEVEL
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let level: u32 = match scalar_u32(&lox_cred.trust_level) {
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Some(v) => v,
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None => return Err(ProofError::VerificationFailure),
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};
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if level < MIN_TRUST_LEVEL {
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return Err(ProofError::VerificationFailure);
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}
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// Blind showing the Lox credential
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// Reblind P and Q
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let mut rng = rand::thread_rng();
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let t_lox = Scalar::random(&mut rng);
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let P_lox = t_lox * lox_cred.P;
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let Q_lox = t_lox * lox_cred.Q;
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// Form Pedersen commitments to the blinded attributes
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let zbucket = Scalar::random(&mut rng);
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let zsince = Scalar::random(&mut rng);
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let zinvremain = Scalar::random(&mut rng);
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let zblockages = Scalar::random(&mut rng);
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let CBucket = lox_cred.bucket * P_lox + &zbucket * Atable;
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let CSince = lox_cred.level_since * P_lox + &zsince * Atable;
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let CInvRemain = lox_cred.invites_remaining * P_lox + &zinvremain * Atable;
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let CBlockages = lox_cred.blockages * P_lox + &zblockages * Atable;
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// Form a Pedersen commitment to the MAC Q
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// We flip the sign of zQ from that of the Hyphae paper so that
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// the ZKP has a "+" instead of a "-", as that's what the zkp
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// macro supports.
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let negzQ_lox = Scalar::random(&mut rng);
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let CQ_lox = Q_lox - &negzQ_lox * Atable;
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// Compute the "error factor"
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let V_lox = zbucket * lox_pub.X[2]
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+ zsince * lox_pub.X[4]
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+ zinvremain * lox_pub.X[5]
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+ zblockages * lox_pub.X[6]
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+ &negzQ_lox * Atable;
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// Blind showing the Migration credential
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// Reblind P and Q
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let t_mig = Scalar::random(&mut rng);
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let P_mig = t_mig * migration_cred.P;
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let Q_mig = t_mig * migration_cred.Q;
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// Form Pedersen commitments to the blinded attributes
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let zfrombucket = Scalar::random(&mut rng);
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let ztobucket = Scalar::random(&mut rng);
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let CFromBucket = migration_cred.from_bucket * P_mig + &zfrombucket * Atable;
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let CToBucket = migration_cred.to_bucket * P_mig + &ztobucket * Atable;
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// Form a Pedersen commitment to the MAC Q
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// We flip the sign of zQ from that of the Hyphae paper so that
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// the ZKP has a "+" instead of a "-", as that's what the zkp
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// macro supports.
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let negzQ_mig = Scalar::random(&mut rng);
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let CQ_mig = Q_mig - &negzQ_mig * Atable;
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// Compute the "error factor"
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let V_mig =
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zfrombucket * migration_pub.X[2] + ztobucket * migration_pub.X[3] + &negzQ_mig * Atable;
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// User blinding for the Lox certificate to be issued
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// Pick an ElGamal keypair
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let d = Scalar::random(&mut rng);
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let D = &d * Btable;
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// Pick a random client component of the id
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let id_client = Scalar::random(&mut rng);
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// Encrypt it (times the basepoint B) to the ElGamal public key D we
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// just created
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let eid_client = Scalar::random(&mut rng);
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let EncIdClient = (&eid_client * Btable, &id_client * Btable + eid_client * D);
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// Encrypt the other blinded attributes (times B) to D as well
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let ebucket = Scalar::random(&mut rng);
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let EncBucket = (
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&ebucket * Btable,
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&migration_cred.to_bucket * Btable + ebucket * D,
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);
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let eblockages = Scalar::random(&mut rng);
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let new_blockages = lox_cred.blockages + Scalar::one();
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let EncBlockages = (
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&eblockages * Btable,
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&new_blockages * Btable + eblockages * D,
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);
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// Construct the proof
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let mut transcript = Transcript::new(b"blockage migration request");
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let piUser = requestproof::prove_compact(
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&mut transcript,
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requestproof::ProveAssignments {
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A: &A,
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B: &B,
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P_lox: &P_lox,
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CBucket: &CBucket,
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CSince: &CSince,
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CInvRemain: &CInvRemain,
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CBlockages: &CBlockages,
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V_lox: &V_lox,
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Xbucket: &lox_pub.X[2],
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Xsince: &lox_pub.X[4],
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Xinvremain: &lox_pub.X[5],
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Xblockages: &lox_pub.X[6],
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P_mig: &P_mig,
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CFromBucket: &CFromBucket,
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CToBucket: &CToBucket,
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V_mig: &V_mig,
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Xfrombucket: &migration_pub.X[2],
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Xtobucket: &migration_pub.X[3],
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D: &D,
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EncIdClient0: &EncIdClient.0,
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EncIdClient1: &EncIdClient.1,
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EncBucket0: &EncBucket.0,
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EncBucket1: &EncBucket.1,
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EncBlockages0: &EncBlockages.0,
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EncBlockages1_minus_B: &(EncBlockages.1 - B),
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bucket: &lox_cred.bucket,
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since: &lox_cred.level_since,
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invremain: &lox_cred.invites_remaining,
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blockages: &lox_cred.blockages,
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zbucket: &zbucket,
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zsince: &zsince,
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zinvremain: &zinvremain,
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zblockages: &zblockages,
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negzQ_lox: &negzQ_lox,
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tobucket: &migration_cred.to_bucket,
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zfrombucket: &zfrombucket,
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ztobucket: &ztobucket,
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negzQ_mig: &negzQ_mig,
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d: &d,
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eid_client: &eid_client,
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ebucket: &ebucket,
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eblockages: &eblockages,
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id_client: &id_client,
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},
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)
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.0;
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Ok((
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Request {
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P_lox,
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id: lox_cred.id,
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CBucket,
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trust_level: lox_cred.trust_level,
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CSince,
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CInvRemain,
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CBlockages,
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CQ_lox,
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P_mig,
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CFromBucket,
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CToBucket,
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CQ_mig,
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D,
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EncIdClient,
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EncBucket,
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EncBlockages,
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piUser,
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},
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State {
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d,
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D,
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EncIdClient,
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EncBucket,
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EncBlockages,
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id_client,
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to_bucket: migration_cred.to_bucket,
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trust_level: (level - 2).into(),
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blockages: new_blockages,
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},
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))
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}
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impl BridgeAuth {
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/// Receive a blockage migration request
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pub fn handle_blockage_migration(&mut self, req: Request) -> Result<Response, ProofError> {
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let A: &RistrettoPoint = &CMZ_A;
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let B: &RistrettoPoint = &CMZ_B;
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let Atable: &RistrettoBasepointTable = &CMZ_A_TABLE;
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let Btable: &RistrettoBasepointTable = &CMZ_B_TABLE;
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if req.P_lox.is_identity() || req.P_mig.is_identity() {
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return Err(ProofError::VerificationFailure);
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}
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// The trust level must be at least MIN_TRUST_LEVEL
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let level: u32 = match scalar_u32(&req.trust_level) {
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Some(v) => v,
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None => return Err(ProofError::VerificationFailure),
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};
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if level < MIN_TRUST_LEVEL {
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return Err(ProofError::VerificationFailure);
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}
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// Recompute the "error factors" using knowledge of our own
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// (the issuer's) private key instead of knowledge of the
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// hidden attributes
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let Vprime_lox = (self.lox_priv.x[0]
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+ self.lox_priv.x[1] * req.id
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+ self.lox_priv.x[3] * req.trust_level)
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* req.P_lox
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+ self.lox_priv.x[2] * req.CBucket
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+ self.lox_priv.x[4] * req.CSince
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+ self.lox_priv.x[5] * req.CInvRemain
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+ self.lox_priv.x[6] * req.CBlockages
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- req.CQ_lox;
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let migration_type: Scalar = MigrationType::Blockage.into();
|
||||
let Vprime_mig = (self.migration_priv.x[0]
|
||||
+ self.migration_priv.x[1] * req.id
|
||||
+ self.migration_priv.x[4] * migration_type)
|
||||
* req.P_mig
|
||||
+ self.migration_priv.x[2] * req.CFromBucket
|
||||
+ self.migration_priv.x[3] * req.CToBucket
|
||||
- req.CQ_mig;
|
||||
|
||||
// Verify the ZKP
|
||||
let mut transcript = Transcript::new(b"blockage migration request");
|
||||
requestproof::verify_compact(
|
||||
&req.piUser,
|
||||
&mut transcript,
|
||||
requestproof::VerifyAssignments {
|
||||
A: &A.compress(),
|
||||
B: &B.compress(),
|
||||
P_lox: &req.P_lox.compress(),
|
||||
CBucket: &req.CBucket.compress(),
|
||||
CSince: &req.CSince.compress(),
|
||||
CInvRemain: &req.CInvRemain.compress(),
|
||||
CBlockages: &req.CBlockages.compress(),
|
||||
V_lox: &Vprime_lox.compress(),
|
||||
Xbucket: &self.lox_pub.X[2].compress(),
|
||||
Xsince: &self.lox_pub.X[4].compress(),
|
||||
Xinvremain: &self.lox_pub.X[5].compress(),
|
||||
Xblockages: &self.lox_pub.X[6].compress(),
|
||||
P_mig: &req.P_mig.compress(),
|
||||
CFromBucket: &req.CFromBucket.compress(),
|
||||
CToBucket: &req.CToBucket.compress(),
|
||||
V_mig: &Vprime_mig.compress(),
|
||||
Xfrombucket: &self.migration_pub.X[2].compress(),
|
||||
Xtobucket: &self.migration_pub.X[3].compress(),
|
||||
D: &req.D.compress(),
|
||||
EncIdClient0: &req.EncIdClient.0.compress(),
|
||||
EncIdClient1: &req.EncIdClient.1.compress(),
|
||||
EncBucket0: &req.EncBucket.0.compress(),
|
||||
EncBucket1: &req.EncBucket.1.compress(),
|
||||
EncBlockages0: &req.EncBlockages.0.compress(),
|
||||
EncBlockages1_minus_B: &(req.EncBlockages.1 - B).compress(),
|
||||
},
|
||||
)?;
|
||||
|
||||
// Ensure the id has not been seen before, and add it to the
|
||||
// seen list.
|
||||
if self.id_filter.filter(&req.id) == SeenType::Seen {
|
||||
return Err(ProofError::VerificationFailure);
|
||||
}
|
||||
|
||||
// Blind issuing of the new Lox credential
|
||||
|
||||
// Choose a random server id component to add to the client's
|
||||
// (blinded) id component
|
||||
let mut rng = rand::thread_rng();
|
||||
let id_server = Scalar::random(&mut rng);
|
||||
let EncId = (req.EncIdClient.0, req.EncIdClient.1 + &id_server * Btable);
|
||||
|
||||
// Create the trust_level attrubute (Scalar), which will be
|
||||
// 2 levels down from the one in the provided credential
|
||||
let trust_level: Scalar = (level - 2).into();
|
||||
|
||||
// Create the level_since attribute (Scalar), which is today's
|
||||
// Julian date
|
||||
let level_since: Scalar = self.today().into();
|
||||
|
||||
// The invites remaining is the appropriate number for the new
|
||||
// level (note that LEVEL_INVITATIONS[i] is the number of
|
||||
// invitations for moving from level i to level i+1)
|
||||
let invremain: Scalar = LEVEL_INVITATIONS[(level - 3) as usize].into();
|
||||
|
||||
// Because of the bug in the zkp crate, encrypt the invites
|
||||
// remaining instead of sending it in the clear
|
||||
let sinvremain = Scalar::random(&mut rng);
|
||||
let EncInvRemain = (
|
||||
&sinvremain * Btable,
|
||||
&invremain * Btable + sinvremain * req.D,
|
||||
);
|
||||
|
||||
// Compute the MAC on the visible attributes
|
||||
let b = Scalar::random(&mut rng);
|
||||
let P = &b * Btable;
|
||||
let QHc = (self.lox_priv.x[0]
|
||||
+ self.lox_priv.x[3] * trust_level
|
||||
+ self.lox_priv.x[4] * level_since)
|
||||
* P;
|
||||
|
||||
// El Gamal encrypt it to the public key req.D
|
||||
let s = Scalar::random(&mut rng);
|
||||
let EncQHc = (&s * Btable, QHc + s * req.D);
|
||||
|
||||
// Homomorphically compute the part of the MAC corresponding to
|
||||
// the blinded attributes
|
||||
let tid = self.lox_priv.x[1] * b;
|
||||
let TId = &tid * Atable;
|
||||
let EncQId = (tid * EncId.0, tid * EncId.1);
|
||||
let tbucket = self.lox_priv.x[2] * b;
|
||||
let TBucket = &tbucket * Atable;
|
||||
let EncQBucket = (tbucket * req.EncBucket.0, tbucket * req.EncBucket.1);
|
||||
let tinvremain = self.lox_priv.x[5] * b;
|
||||
let TInvRemain = &tinvremain * Atable;
|
||||
let EncQInvRemain = (tinvremain * EncInvRemain.0, tinvremain * EncInvRemain.1);
|
||||
let tblockages = self.lox_priv.x[6] * b;
|
||||
let TBlockages = &tblockages * Atable;
|
||||
let EncQBlockages = (
|
||||
tblockages * req.EncBlockages.0,
|
||||
tblockages * req.EncBlockages.1,
|
||||
);
|
||||
|
||||
let EncQ = (
|
||||
EncQHc.0 + EncQId.0 + EncQBucket.0 + EncQInvRemain.0 + EncQBlockages.0,
|
||||
EncQHc.1 + EncQId.1 + EncQBucket.1 + EncQInvRemain.1 + EncQBlockages.1,
|
||||
);
|
||||
|
||||
let mut transcript = Transcript::new(b"blockage migration issuing");
|
||||
let piBlindIssue = blindissue::prove_compact(
|
||||
&mut transcript,
|
||||
blindissue::ProveAssignments {
|
||||
A: &A,
|
||||
B: &B,
|
||||
P: &P,
|
||||
EncQ0: &EncQ.0,
|
||||
EncQ1: &EncQ.1,
|
||||
X0: &self.lox_pub.X[0],
|
||||
Xid: &self.lox_pub.X[1],
|
||||
Xbucket: &self.lox_pub.X[2],
|
||||
Xlevel: &self.lox_pub.X[3],
|
||||
Xsince: &self.lox_pub.X[4],
|
||||
Xinvremain: &self.lox_pub.X[5],
|
||||
Xblockages: &self.lox_pub.X[6],
|
||||
Plevel: &(trust_level * P),
|
||||
Psince: &(level_since * P),
|
||||
TId: &TId,
|
||||
TBucket: &TBucket,
|
||||
TInvRemain: &TInvRemain,
|
||||
TBlockages: &TBlockages,
|
||||
D: &req.D,
|
||||
EncId0: &EncId.0,
|
||||
EncId1: &EncId.1,
|
||||
EncBucket0: &req.EncBucket.0,
|
||||
EncBucket1: &req.EncBucket.1,
|
||||
EncInvRemain0: &EncInvRemain.0,
|
||||
EncInvRemain1: &EncInvRemain.1,
|
||||
EncBlockages0: &req.EncBlockages.0,
|
||||
EncBlockages1: &req.EncBlockages.1,
|
||||
x0: &self.lox_priv.x[0],
|
||||
x0tilde: &self.lox_priv.x0tilde,
|
||||
xid: &self.lox_priv.x[1],
|
||||
xbucket: &self.lox_priv.x[2],
|
||||
xlevel: &self.lox_priv.x[3],
|
||||
xsince: &self.lox_priv.x[4],
|
||||
xinvremain: &self.lox_priv.x[5],
|
||||
xblockages: &self.lox_priv.x[6],
|
||||
s: &s,
|
||||
b: &b,
|
||||
tid: &tid,
|
||||
tbucket: &tbucket,
|
||||
tinvremain: &tinvremain,
|
||||
tblockages: &tblockages,
|
||||
},
|
||||
)
|
||||
.0;
|
||||
|
||||
Ok(Response {
|
||||
level_since,
|
||||
P,
|
||||
EncQ,
|
||||
EncInvRemain,
|
||||
id_server,
|
||||
TId,
|
||||
TBucket,
|
||||
TInvRemain,
|
||||
TBlockages,
|
||||
piBlindIssue,
|
||||
})
|
||||
}
|
||||
}
|
||||
|
||||
/// Handle the response to the request, producing the new Lox credential
|
||||
/// if successful.
|
||||
pub fn handle_response(
|
||||
state: State,
|
||||
resp: Response,
|
||||
lox_pub: &IssuerPubKey,
|
||||
) -> Result<cred::Lox, ProofError> {
|
||||
let A: &RistrettoPoint = &CMZ_A;
|
||||
let B: &RistrettoPoint = &CMZ_B;
|
||||
let Btable: &RistrettoBasepointTable = &CMZ_B_TABLE;
|
||||
|
||||
if resp.P.is_identity() {
|
||||
return Err(ProofError::VerificationFailure);
|
||||
}
|
||||
|
||||
// Add the server's contribution to the id to our own, both in plain
|
||||
// and encrypted form
|
||||
let id = state.id_client + resp.id_server;
|
||||
let EncId = (
|
||||
state.EncIdClient.0,
|
||||
state.EncIdClient.1 + &resp.id_server * Btable,
|
||||
);
|
||||
|
||||
let new_level: u32 = match scalar_u32(&state.trust_level) {
|
||||
Some(v) => v,
|
||||
None => return Err(ProofError::VerificationFailure),
|
||||
};
|
||||
if new_level < 1 {
|
||||
return Err(ProofError::VerificationFailure);
|
||||
}
|
||||
|
||||
// The invites remaining is the appropriate number for the new level
|
||||
// (note that LEVEL_INVITATIONS[i] is the number of invitations for
|
||||
// moving from level i to level i+1)
|
||||
let invremain: Scalar = LEVEL_INVITATIONS[(new_level - 1) as usize].into();
|
||||
|
||||
// Decrypt EncInvRemain
|
||||
let recv_invremain = resp.EncInvRemain.1 - (state.d * resp.EncInvRemain.0);
|
||||
|
||||
if recv_invremain != &invremain * Btable {
|
||||
return Err(ProofError::VerificationFailure);
|
||||
}
|
||||
|
||||
// Verify the proof
|
||||
let mut transcript = Transcript::new(b"blockage migration issuing");
|
||||
blindissue::verify_compact(
|
||||
&resp.piBlindIssue,
|
||||
&mut transcript,
|
||||
blindissue::VerifyAssignments {
|
||||
A: &A.compress(),
|
||||
B: &B.compress(),
|
||||
P: &resp.P.compress(),
|
||||
EncQ0: &resp.EncQ.0.compress(),
|
||||
EncQ1: &resp.EncQ.1.compress(),
|
||||
X0: &lox_pub.X[0].compress(),
|
||||
Xid: &lox_pub.X[1].compress(),
|
||||
Xbucket: &lox_pub.X[2].compress(),
|
||||
Xlevel: &lox_pub.X[3].compress(),
|
||||
Xsince: &lox_pub.X[4].compress(),
|
||||
Xinvremain: &lox_pub.X[5].compress(),
|
||||
Xblockages: &lox_pub.X[6].compress(),
|
||||
Plevel: &(state.trust_level * resp.P).compress(),
|
||||
Psince: &(resp.level_since * resp.P).compress(),
|
||||
TId: &resp.TId.compress(),
|
||||
TBucket: &resp.TBucket.compress(),
|
||||
TInvRemain: &resp.TInvRemain.compress(),
|
||||
TBlockages: &resp.TBlockages.compress(),
|
||||
D: &state.D.compress(),
|
||||
EncId0: &EncId.0.compress(),
|
||||
EncId1: &EncId.1.compress(),
|
||||
EncBucket0: &state.EncBucket.0.compress(),
|
||||
EncBucket1: &state.EncBucket.1.compress(),
|
||||
EncInvRemain0: &resp.EncInvRemain.0.compress(),
|
||||
EncInvRemain1: &resp.EncInvRemain.1.compress(),
|
||||
EncBlockages0: &state.EncBlockages.0.compress(),
|
||||
EncBlockages1: &state.EncBlockages.1.compress(),
|
||||
},
|
||||
)?;
|
||||
|
||||
// Decrypt EncQ
|
||||
let Q = resp.EncQ.1 - (state.d * resp.EncQ.0);
|
||||
|
||||
Ok(cred::Lox {
|
||||
P: resp.P,
|
||||
Q,
|
||||
id,
|
||||
bucket: state.to_bucket,
|
||||
trust_level: new_level.into(),
|
||||
level_since: resp.level_since,
|
||||
invites_remaining: invremain,
|
||||
blockages: state.blockages,
|
||||
})
|
||||
}
|
||||
|
|
@ -1,9 +1,8 @@
|
|||
/*! A module for the protocol for the user to migrate from one bucket to
|
||||
another (and possibly also change trust level).
|
||||
another and change trust level from untrusted (trust level 0) to trusted
|
||||
(trust level 1).
|
||||
|
||||
For the case of migrating from trust level 0 (a one-bridge bucket) to
|
||||
trust level 1 (a three-bridge bucket), the user presents their current
|
||||
Lox credential:
|
||||
The user presents their current Lox credential:
|
||||
|
||||
- id: revealed
|
||||
- bucket: blinded
|
||||
|
|
@ -163,8 +162,8 @@ pub fn request(
|
|||
return Err(ProofError::VerificationFailure);
|
||||
}
|
||||
|
||||
// We only support migrating from trust level 0 to trust level 1
|
||||
// right now
|
||||
// This protocol only allows migrating from trust level 0 to trust
|
||||
// level 1
|
||||
if lox_cred.trust_level != Scalar::zero() {
|
||||
return Err(ProofError::VerificationFailure);
|
||||
}
|
||||
|
|
|
|||
|
|
@ -126,6 +126,14 @@ impl TestHarness {
|
|||
let resp = self.ba.handle_check_blockage(req).unwrap();
|
||||
check_blockage::handle_response(state, resp).unwrap()
|
||||
}
|
||||
|
||||
fn blockage_migration(&mut self, cred: &cred::Lox, mig: &cred::Migration) -> cred::Lox {
|
||||
let (req, state) =
|
||||
blockage_migration::request(&cred, &mig, &self.ba.lox_pub, &self.ba.migration_pub)
|
||||
.unwrap();
|
||||
let resp = self.ba.handle_blockage_migration(req).unwrap();
|
||||
blockage_migration::handle_response(state, resp, &self.ba.lox_pub).unwrap()
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
|
|
@ -358,7 +366,7 @@ fn test_mark_unreachable() {
|
|||
}
|
||||
|
||||
#[test]
|
||||
fn test_check_blockage() {
|
||||
fn test_blockage_migration() {
|
||||
let mut th = TestHarness::new();
|
||||
|
||||
// Join an untrusted user
|
||||
|
|
@ -420,4 +428,10 @@ fn test_check_blockage() {
|
|||
let migration = th.check_blockage(&cred3);
|
||||
|
||||
println!("migration = {:?}", migration);
|
||||
|
||||
// Migrate
|
||||
let cred4 = th.blockage_migration(&cred3, &migration);
|
||||
|
||||
println!("cred4 = {:?}", cred4);
|
||||
assert!(th.ba.verify_lox(&cred4));
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue