Skip to content

WIP: allow overcontributing randomness #3

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 1 commit into from
Closed

WIP: allow overcontributing randomness #3

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
26 changes: 16 additions & 10 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -41,13 +41,13 @@ Also, SimplePedPop requires an interactive protocol `Eq` as described in section
While SimplPedPop is able to identify participants who are misbehaving in certain ways, it is easy for a participant to misbehave such that it will not be identified.

```python
def simplpedpop_setup(seed, t, ids):
def simplpedpop_setup(seed, t, signer_ids):
"""
Start SimplPedPop by generating messages to send to the other participants.

:param bytes seed: FRESH, UNIFORMLY RANDOM 32-byte string
:param int t: threshold
:param List[bytes] ids: 33-bytes that identify the participants, must be unique
:param List[bytes] signer_ids: 33-bytes that identify the future signers, must be unique
:return: a VSS commitment and shares
"""
f = polynomial_gen(seed)
Expand All @@ -58,30 +58,36 @@ def simplpedpop_setup(seed, t, ids):
assert(vss_commit[0] == pubkey_gen(sk))
sig = sign(sk, "")
vss_commit = vss_commit || sig
shares = [ f(hash_sometag(id)) for id in ids ]
shares = [ f(hash_sometag(id)) for id in signer_ids ]
return vss_commit, shares
```

In SimplPedPop every participant has secure channels to every other participant.
For every other participant `id[i]`, the participant sends `vss_commit` and `shares[i]` through the secure channel.

```python
def simplpedpop_finalize(ids, my_id, vss_commits, shares, eta = {}):
def simplpedpop_finalize(ids, n, my_id, vss_commits, shares, eta = {}):
"""
Take the messages received from the participants and finalize the DKG

:param List[bytes] ids: 33-bytes that identify the participants, must be unique
:param List[bytes] ids: 33-bytes that identify the future signers and input contributors
the first n ids are future signers, the rest are contributors, must be unique
:param integer n: number of signers
:param my_id bytes: 33-bytes that identify this participant, must be in ids
:param List[bytes] vss_commits: VSS commitments from all participants
(including myself, TODO: it's unnecessary that we verify our own vss_commit)
:param List[bytes] shares: shares from all participants (including this participant)
:param eta: Optional argument for extra data that goes into `Eq`
:return: a final share, the shared pubkey, the individual participants' pubkeys
"""
n = len(ids)
assert(n == len(share) and n == len(vss_commits))
for i in range(n):
if not verify_vss(my_id, vss_commits[i], shares[i]):
q = len(ids)
is_signer = ids.index(my_id) < n # TODO: deal with duplicates
assert(q >= n)
if is_signer:
assert(q == len(shares))
assert(q == len(vss_commits))
for i in range(q):
if is_signer and not verify_vss(my_id, vss_commits[i], shares[i]):
throw BadParticipant(ids[i])
if not verify_sig(vss_commits[i].sig, vss_commits[i][0], "")
throw BadParticipant(ids[i])
Expand All @@ -92,7 +98,7 @@ def simplpedpop_finalize(ids, my_id, vss_commits, shares, eta = {}):
return False
# helper_compute_pk computes the individual pubkey of participant with the given id
signer_pubkeys = [helper_compute_pk(vss_commits, t, ids[i]) for i in range(n)]
pubkey = sum([vss_commits[i][0] for i in range(n)])
pubkey = sum([vss_commits[i][0] for i in range(q)])
return sum(shares), pubkey, signer_pubkeys
```

Expand Down