ZK Credentials Preparator

Zero Knowledge Credentials (ZKC) Preparator is a library designed to assist developers in getting Zero Knowledge Credentials ready for use with Zero Knowledge Proof (ZKP) functions according to ZKC protocol (see ZK Credential: Preparation & Transformation Graphsections ).

API

Prepare ZK Credential

const zkCredential: ZKCredential = {
  isr: {
    id: { t: 1, k: "123456" }
  },
  sch: 1,
  isd: new Date().getTime(),
  exd: new Date().getTime(),
  sbj: {
    id: { k: "2345678", t: 2, },
    eth: "0x2...3",
    alias: "Test",
  }
};

const transSchema: TransCredSchema = {
  isr: {
    id: {
      t: ["uint32-bytes", "bytes-uint32", "uint32-boolean"],
      k: ["utf8-bytes"]
    },
  },
  sch: ["uint32-bytes", "bytes-base16"],
  isd: ["uint64-bytes", "bytes-base32"],
  exd: ["uint64-bytes", "bytes-utf8"],
  sbj: {
    id: {
      t: ["uint32-bytes"],
      k: ["utf8-bytes", "bytes-base16"]
    },
    alias: ["ascii-bytes", "bytes-uint128"],
    eth: ["utf8-bytes", "bytes-uint256"]
  }
};

const preparator = new Preparator();
const [
  isr_id_t, // boolean type
  isr_id_k, // Uint8Array
  sch,      // string as base16
  isd,      // string as base32
  exd,      // string as utf8
  sbj_id_t, // Uint8Array
  sbj_id_k, // string as base16
  alias,    // bigint
  eth       // bigint
] = preparator.prepare(zkCredential, transSchema);

Extend transformation graph

const preparator = new Preparator();
preparator.extendGraph([{ // extend transformation nodes
  name: "newNode",
  isType: (value: any) => value === "hello ZKCredentials"
}], [{ // extend transformation links
  inputType: "bytes",
  outputType: "bytes",
  name: "bytes.reverse",
  transform: (bytes: Uint8Array) => bytes.reverse()
}]);

Match between Transformation Graph types (nodes) and JS types

| Name | Description | JS Types | |-----------|-------------------------------------------------------------------------------------------------|---------------------------------------------------------------------| | utf8 | UTF-8 encoded string, according to https://datatracker.ietf.org/doc/html/rfc3629 | string | | base64 | Base64 encoded string, according to https://datatracker.ietf.org/doc/html/rfc3629 | string | | base32 | Base32 encoded string, according to https://datatracker.ietf.org/doc/html/rfc3629 | string | | base16 | Base16 encoded string, according to https://datatracker.ietf.org/doc/html/rfc3629 | string | | base64url | Base64url encoded string, according to https://datatracker.ietf.org/doc/html/rfc7515#appendix-C | string | | base58 | Base58 encoded string, according to https://en.bitcoin.it/wiki/Base58Check_encoding | string | | ascii | ACSII encoded string, according to https://datatracker.ietf.org/doc/html/rfc20 | string | | int16 | Integer 16 bits size | number or bigint as input type for link, only bigint as output type | | int32 | Integer 32 bits size | number or bigint as input type for link, only bigint as output type | | int64 | Integer 64 bits size | number or bigint as input type for link, only bigint as output type | | int128 | Integer 128 bits size | number or bigint as input type for link, only bigint as output type | | int256 | Integer 256 bits size | number or bigint as input type for link, only bigint as output type | | uint16 | Unsigned integer 16 bits size | number or bigint as input type for link, only bigint as output type | | uint32 | Unsigned integer 32 bits size | number or bigint as input type for link, only bigint as output type | | uint64 | Unsigned integer 64 bits size | number or bigint as input type for link, only bigint as output type | | uint128 | Unsigned integer 128 bits size | number or bigint as input type for link, only bigint as output type | | uint256 | Unsigned integer 256 bits size | number or bigint as input type for link, only bigint as output type | | uint | Unsigned integer withoout limits | number or bigint as input type for link, only bigint as output type | | float32 | Float according to IEEE 754 | number | | boolean | Boolean | boolean | | bytes | bytes array | Uint8Array |