# max-dpd-max-v1: key ceremony transcript

Everything below is also in `circuit.json` (field `ceremony`). Times are UTC.

| | |
|---|---|
| Circuit | `max-dpd-max-v1` = zk-kit `range_b16_n` (range, {"bits":16,"nonce":true}), 321 constraints |
| circuitId | `0x58085a5840732bbf24e7a82543ba464aadd09b7f8016fd72090b70e55f7ddb1e` = keccak256("max-dpd-max-v1") |
| Public signals | `commitment`, `min`, `max`, `nonce` |
| vkHash | `0xfd89182dca732a03c56fe579a68e69d0abf4baee13fa87fa26f44904d7bf7989` = keccak256(JCS(verification_key.json)) |
| ceremonyContributions (registry) | 1 |

## Phase 1: public Powers of Tau

The PSE Perpetual Powers of Tau (80 participants, closed with a pre-announced Ethereum randao
beacon), response 0080 prepared for phase 2 and truncated to 2^9.

| | |
|---|---|
| URL | https://pse-trusted-setup-ppot.s3.eu-central-1.amazonaws.com/pot28_0080/ppot_0080_09.ptau |
| Size | 683,154 bytes |
| blake2b-512 | `33ccbcacd7c43238b540f8dd7f68b4acac6be3a1fe2e695d55aea291172d30ddc8056c2851f5660b5e795550f300660042072254813d1558dc4d5a7192eae9b6` |
| sha256 | `67e59e346767e179a5bd88b4789a56ce376708244c01a32b520ee208dbfb2595` |
| Header power | 2^9 (read from the file header) |
| S3 ETag | `69d89d14fb047514a1eb6c82ffd5a718` (last modified Tue, 09 Apr 2024 07:02:55 GMT); md5 matches |
| Downloaded | 2026-09-27T06:12:41.730Z |

PSE publishes no hash list for the prepared files, so the checks above are what could be made: the
header, the byte count, and the S3 multipart ETag recomputed from the bytes (a transport check, not
an authenticity check). snarkjs's full powers-of-tau verification was not run: it did not finish in
10 minutes even for the 2^8 file on the build machine. Download the file yourself and compare the
blake2b-512 before you rely on it.

## Phase 2

1. **Initial key** `_0000` = snarkjs `zkey new` of `max-dpd-max-v1.r1cs` on the phase-1 file. It is
   deterministic; anyone can recreate it (196,384 bytes, blake2b-512
   `b8527be6b115bb67ebb735f2c43abeb0925abaa2951064876a888f76a1ec041fa09c06410e1ba7f1c8426aba20da116519e355892f43cab8607cc8bc60a875bb`).
2. **Contribution #1: Super Wallet (SeoulLabs) phase-2 contribution**, 2026-09-27T06:12:57.038Z to 2026-09-27T06:12:57.118Z.
   Contribution hash:

   ```
   caa0bb78c2d11f2a66dce7e616f97c44c1028e0cc94277c0ca0ef139fc915bc9c4a09e3dc7957d81f97748cc74c1350b9c35978c377116bb6d4b2d58cae9628f
   ```

   Entropy: 64 bytes from the operating system CSPRNG (`node:crypto` randomBytes), passed in
   memory to snarkjs, which mixes in its own random bytes. It was not written to disk, a log or a
   terminal, and the process has exited. All seven circuits of ceremony batch 2 were contributed in one
   run that finished at 2026-09-27T06:13:03.218Z.
3. **Beacon.** The rule, fixed in `zk-kit/scripts/production-ceremony.ts` before the run: after
   every contribution has finished, take the latest Xphere mainnet block whose timestamp is later
   than that moment, and apply its hash with 2^10 iterations (snarkjs `zkey beacon`).

   | | |
   |---|---|
   | Chain | Xphere mainnet, chain id 20250217 (read from https://en-hkg.x-phere.com) |
   | Block | 49689564 |
   | Block hash | `0xf881b8862fb95d63b2269b5a6e6ae228156d78250e72c9c7129901b460d820de` |
   | Block time | 2026-09-27T06:13:14.000Z (fetched 2026-09-27T06:13:13.528Z) |
   | Iterations | 2^10 |
   | Beacon contribution hash | `ad27c4d0e4f6d112c81e752886291b989f0b220e4d2756d1e710932d32afb99f4a498585067457bb4e374d55b0ebcba0138c3e9f7ed0758fdc10b0c1e2fbb01a` |

   Check the block: `curl -s -X POST -H 'content-type: application/json' --data '{"jsonrpc":"2.0","id":1,"method":"eth_getBlockByNumber","params":["0x2f633dc",false]}' https://en-hkg.x-phere.com`
   and compare `hash`, or open https://xp.tamsa.io/block/49689564.

## What this ceremony does and does not give you

A Groth16 phase 2 is sound if **at least one** contributor destroyed their randomness. This key has
**one** contributor, Super Wallet, so its soundness rests on Super Wallet having done so. The public
beacon makes the final key depend on a value nobody knew when the contribution was made, but it is
public and adds no secret: it does not replace a second, independent contributor. The block number
was not announced in advance; the rule for picking it was fixed in the script, and the block came
after the contribution. The registry records `ceremonyContributions = 1` as it is.

**An institution that wants to add its own contribution** takes `max-dpd-max-v1.zkey` (this key; the
contribution chain inside it continues), checks it with `zk-kit verify-ceremony`, runs
`zk-kit contribute`, and hands the result back; Super Wallet then applies a new, pre-announced
beacon with `zk-kit finalize`. The result is a new key and therefore a new circuit id,
`max-dpd-max-v2`, registered alongside this one with ceremonyContributions = 2. A
key is never swapped in under an existing circuit id.

## Result

| | |
|---|---|
| verifyFromR1cs (r1cs + phase-1 file + zkey) | OK |
| Circuit hash (snarkjs) | `1f343a85bbfb48a1bbd86c2600a15cc5998deb02082bb1063f209405d3be8665e38105daea204dda1a26871ab42f2a6022e15f850d9ac4d29e296d89c17a6e52` |
| `max-dpd-max-v1.zkey` | 197,289 bytes, sha256 `2047eff05cc54c5a96adecf0cdf1d6339e408d26bfb24de431f2115b427a3eb3`, blake2b-512 `48f3205b208dfe8e83b7fcd130d762e4ea92ed68861501927345adb82cd3a1cffc71c72d8629d4ab4d2edce3a7677e4b6c611047eb8ffdb698a3aecf4b611ec8` |
| `max-dpd-max-v1.r1cs` | 130,344 bytes, sha256 `2f32f5d7bb3c5f53396cce353362f0c5e2da5fda9455ada783bdaa6c8b6f3694` |
| `max-dpd-max-v1.wasm` | 1,753,948 bytes, sha256 `951cf295d2d3a5e67743d39d8dc72d7e17e7b241880174c6b6e2d24301a6bf0a` |
| vkHash | `0xfd89182dca732a03c56fe579a68e69d0abf4baee13fa87fa26f44904d7bf7989` |
| Verifier.sol runtime keccak256 (solc 0.8.24, optimizer 200, paris) | `0x3d7c467e0cb6eb841aada84d45fc143b8735f44c3cc16cb277d0e48b8aa29d3b` |

## Check it yourself

```sh
npm install /path/to/zk-kit          # or: npm install snarkjs@0.7.6 and use snarkjs directly
npx zk-kit ptau --power 9 --public --out ppot_0080_9.ptau   # compare blake2b512 above
npx zk-kit verify-ceremony --r1cs max-dpd-max-v1.r1cs --ptau ppot_0080_9.ptau --zkey max-dpd-max-v1.zkey
# prints: zkey VALID, then #1 Super Wallet (SeoulLabs) phase-2 contribution: caa0bb78c2d11f2a...
#                             #2 Xphere mainnet block 49689564 beacon [beacon f881b8862fb95d63..., 2^10 iterations]
```