@airgap/coinlib-core/utils/base64Check.js

The @airgap/coinlib-core is a protocol agnostic library to prepare, sign and broadcast cryptocurrency transactions.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var createHash = require("../dependencies/src/create-hash-1.2.0/index");
var errors_1 = require("../errors");
var coinlib_error_1 = require("../errors/coinlib-error");
var sha256hash = function (input) {
    var hash = createHash('sha256');
    hash.update(input);
    return hash.digest();
};
var checkSum = function (payload) {
    return sha256hash(sha256hash(payload)).slice(0, 4);
};
var bs64check = {
    encode: function (input) {
        if (!Buffer.isBuffer(input)) {
            input = Buffer.from(input);
        }
        var checksum = checkSum(input);
        var payloadWithChecksum = Buffer.concat([input, checksum], input.length + 4);
        return payloadWithChecksum.toString('base64');
    },
    decode: function (input) {
        if (!Buffer.isBuffer(input)) {
            input = Buffer.from(input, 'base64');
        }
        var payload = input.slice(0, -4);
        var checksum = input.slice(-4);
        var newChecksum = checkSum(payload);
        // tslint:disable-next-line:no-bitwise
        if ((checksum[0] ^ newChecksum[0]) | (checksum[1] ^ newChecksum[1]) | (checksum[2] ^ newChecksum[2]) | (checksum[3] ^ newChecksum[3])) {
            throw new errors_1.ConditionViolationError(coinlib_error_1.Domain.UTILS, 'bs64check checksum does not match');
        }
        return payload;
    },
    checkSum: checkSum
};
exports.default = bs64check;
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