@sybil-center/zkc-preparator

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