zk-email-light/sha.js

ZkEmail only for Header

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.sha256Pad = exports.shaCircuitInputs = exports.sha256 = void 0;
const crypto_1 = require("crypto");
const dkim_verifier_1 = require("dkim-verifier");
const input_1 = require("./input");
const sha256 = (input) => (0, crypto_1.createHash)("sha256").update(input).digest("hex");
exports.sha256 = sha256;
const shaCircuitInputs = (emailRaw) => {
    const { canonicalizedHeaders } = (0, dkim_verifier_1.parseEmailToCanonicalized)(emailRaw);
    const bufferMessage = Buffer.from(canonicalizedHeaders, "ascii");
    const { paddedInput, paddedInLength } = (0, exports.sha256Pad)(bufferMessage, input_1.SHA_PADDED_MESSAGE_LENGTH);
    return {
        paddedIn: Array.from(paddedInput).map(Number),
        paddedInLength,
    };
};
exports.shaCircuitInputs = shaCircuitInputs;
// Copy from https://github.com/zkemail/zk-email-verify/tree/main/packages/helpers
// Works only on 32 bit sha text lengths
const int64toBytes = (num) => {
    const arr = new ArrayBuffer(8); // an Int32 takes 4 bytes
    const view = new DataView(arr);
    view.setInt32(4, num, false); // byteOffset = 0; litteEndian = false
    return new Uint8Array(arr);
};
const mergeUInt8Arrays = (a1, a2) => {
    // sum of individual array lengths
    const mergedArray = new Uint8Array(a1.length + a2.length);
    mergedArray.set(a1);
    mergedArray.set(a2, a1.length);
    return mergedArray;
};
// Works only on 32 bit sha text lengths
const int8toBytes = (num) => {
    const arr = new ArrayBuffer(1); // an Int8 takes 4 bytes
    const view = new DataView(arr);
    view.setUint8(0, num); // byteOffset = 0; litteEndian = false
    return new Uint8Array(arr);
};
// Puts an end selector, a bunch of 0s, then the length, then fill the rest with 0s.
const sha256Pad = (message, maxShaBytes) => {
    const msgLen = message.length * 8; // bytes to bits
    const msgLenBytes = int64toBytes(msgLen);
    let res = mergeUInt8Arrays(message, int8toBytes(2 ** 7)); // Add the 1 on the end, length 505
    // while ((prehash_prepad_m.length * 8 + length_in_bytes.length * 8) % 512 !== 0) {
    while ((res.length * 8 + msgLenBytes.length * 8) % 512 !== 0) {
        res = mergeUInt8Arrays(res, int8toBytes(0));
    }
    res = mergeUInt8Arrays(res, msgLenBytes);
    if ((res.length * 8) % 512 !== 0)
        throw new Error("Padding did not complete properly!");
    const messageLen = res.length;
    while (res.length < maxShaBytes) {
        res = mergeUInt8Arrays(res, int64toBytes(0));
    }
    if (res.length !== maxShaBytes)
        throw new Error(`Padding to max length did not complete properly! Your padded message is ${res.length} long but max is ${maxShaBytes}!`);
    return {
        paddedInput: res,
        paddedInLength: messageLen,
    };
};
exports.sha256Pad = sha256Pad;
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