Mina Credentials

This is where we implement Private Credentials: MinaFoundation/Core-Grants#35 (comment)

mina-credentials/dynamic

Under the import mina-credentials/dynamic, we export an entire library of dynamic data types and hashes with o1js.

Features:

• DynamicSHA2 for hashing dynamic-length inputs with SHA2-256, -224, -384 or -512
• DynamicString and DynamicBytes for representing strings and bytes
• DynamicArray, a generalization of the above types to an arbitrary element type
• StaticArray, which provides an API consistent with DynamicArray but for fixed-length arrays (which aren't well-supported in o1js either)
• DynamicRecord, a wrapper for objects that you don't necessarily know the exact layout of, but can be hashed and accessed properties of inside a circuit
• hashDynamic(), for Poseidon-hashing pretty much any input (including plain strings, records, o1js types etc) in a way which is compatible to in-circuit hashing of padded data types like DynamicRecord and DynamicArray

The library is intended to help with importing real-world credentials into the Mina ecosystem: For example, to "import" your passport, you have to verify the passport authority's signature on your passport data. The signature relies one of several hashing and signature schemes such as ECDSA, RSA and SHA2-256, SHA2-384, SHA2-512. Also, the signature will be over a dynamic-length string.

Example of SHA-512-hashing a dynamic-length string:

import { Bytes, ZkProgram } from 'o1js';
import { DynamicSHA2, DynamicString } from 'mina-credentials/dynamic';

// allow strings up to length 100 as input
const String = DynamicString({ maxLength: 100 });

let sha512Program = ZkProgram({
  name: 'sha512',
  publicOutput: Bytes(64); // 64 bytes == 512 bits

  methods: {
    run: {
      privateInputs: [String],
      async method(string: DynamicString) {
        let publicOutput = DynamicSHA2.hash(512, string);
        return { publicOutput };
      },
    },
  },
});

await sha512Program.compile();

let result = await sha512Program.run(String.from('Hello, world!'));
let provenHash: Bytes = result.proof.publicOutput;

console.log(provenHash.toHex());

License

Apache-2.0

Copyright 2024 zkSecurity

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.