# level-over-v1: key ceremony transcript

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

| | |
|---|---|
| Circuit | `level-over-v1` = zk-kit `threshold_b2_n` (threshold, {"bits":2,"nonce":true}), 247 constraints |
| circuitId | `0x51be11404773e5e731808a6a67a1b894a61794e54f1711d206b3970ed9df9a60` = keccak256("level-over-v1") |
| Public signals | `commitment`, `threshold`, `nonce` |
| vkHash | `0xef9d72749e3ddad09ac797e8c67ba94168a53640c21f4db3a7bedd7ab05b1aa8` = 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 `level-over-v1.r1cs` on the phase-1 file. It is
   deterministic; anyone can recreate it (140,360 bytes, blake2b-512
   `704cfb3588961ebee1d5ccd43211e637257676cbafb1684651e9e3c2985a801a7bded3a062d53f9705c4802265c7597f23cfde9cabe37bc68401cae1ad17598e`).
2. **Contribution #1: Super Wallet (SeoulLabs) phase-2 contribution**, 2026-09-27T06:12:47.584Z to 2026-09-27T06:12:47.634Z.
   Contribution hash:

   ```
   be1cbd80a3c7d921d21ba49aa538d77dbc9e5da55ea508a9d2f45a2b5602b54fb58e5e7aa3909faff21f9f15bdd4fd6a0ca9e525b7b48d62ba563bf470b98cc1
   ```

   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 | `e26677f95d5a731ad101077196d6833935c053a9060780b04ae985485c799917422f9295389bc977381c69bfce84d4e503c93598ed5f3e3bf1810e72cbc9d896` |

   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 `level-over-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,
`level-over-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) | `e7d42745e2f15ba67f4e4ba11fc8ed328027da68d1cd00b86ad75dd82fa3a4b12bd39931d30b6547710b9f8d3edec30bb6fcf7791bc0436d99502778147e1577` |
| `level-over-v1.zkey` | 141,265 bytes, sha256 `1396c60ed0df567ac910bfb87b93ce577fad26540d6bd1706f5667506f1af959`, blake2b-512 `2ba73ee49254d6304065df5b10aeb5b2a441c81314e7fd0c70b1a7b08fabf3fcf86c2cf098ff01429a22b8b89cfdeadbb73336f5441f3458993b594a3869e4e6` |
| `level-over-v1.r1cs` | 115,588 bytes, sha256 `6f4bae33604bda12386555bab3c239ffe522db15bdbe08523f6f94c9d75ca8ff` |
| `level-over-v1.wasm` | 1,752,406 bytes, sha256 `893c16bba48cfd00f24f8b6eea141e86b16449a106a2630f7feac0336740f1f5` |
| vkHash | `0xef9d72749e3ddad09ac797e8c67ba94168a53640c21f4db3a7bedd7ab05b1aa8` |
| Verifier.sol runtime keccak256 (solc 0.8.24, optimizer 200, paris) | `0x8b1ef443b8713dc87ab604610fb27efcfde95fed362e50cc2349093f8244171c` |

## 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 level-over-v1.r1cs --ptau ppot_0080_9.ptau --zkey level-over-v1.zkey
# prints: zkey VALID, then #1 Super Wallet (SeoulLabs) phase-2 contribution: be1cbd80a3c7d921...
#                             #2 Xphere mainnet block 49689564 beacon [beacon f881b8862fb95d63..., 2^10 iterations]
```