113 lines
3.2 KiB
JavaScript
113 lines
3.2 KiB
JavaScript
/*global Promise*/
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(function (exports) {
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'use strict';
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var EC = exports.Eckles = {};
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if ('undefined' !== typeof module) { module.exports = EC; }
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var Enc = {};
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var textEncoder = new TextEncoder();
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EC._stance = "We take the stance that if you're knowledgeable enough to"
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+ " properly and securely use non-standard crypto then you shouldn't need Bluecrypt anyway.";
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EC._universal = "Bluecrypt only supports crypto with standard cross-browser and cross-platform support.";
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EC.generate = function (opts) {
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var wcOpts = {};
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if (!opts) { opts = {}; }
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if (!opts.kty) { opts.kty = 'EC'; }
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// ECDSA has only the P curves and an associated bitlength
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wcOpts.name = 'ECDSA';
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if (!opts.namedCurve) {
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opts.namedCurve = 'P-256';
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}
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wcOpts.namedCurve = opts.namedCurve; // true for supported curves
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if (/256/.test(wcOpts.namedCurve)) {
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wcOpts.namedCurve = 'P-256';
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wcOpts.hash = { name: "SHA-256" };
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} else if (/384/.test(wcOpts.namedCurve)) {
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wcOpts.namedCurve = 'P-384';
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wcOpts.hash = { name: "SHA-384" };
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} else {
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return Promise.Reject(new Error("'" + wcOpts.namedCurve + "' is not an NIST approved ECDSA namedCurve. "
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+ " Please choose either 'P-256' or 'P-384'. "
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+ EC._stance));
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}
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var extractable = true;
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return window.crypto.subtle.generateKey(
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wcOpts
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, extractable
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, [ 'sign', 'verify' ]
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).then(function (result) {
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return window.crypto.subtle.exportKey(
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"jwk"
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, result.privateKey
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).then(function (privJwk) {
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return {
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private: privJwk
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, public: EC.neuter({ jwk: privJwk })
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};
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});
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});
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};
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// Chopping off the private parts is now part of the public API.
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// I thought it sounded a little too crude at first, but it really is the best name in every possible way.
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EC.neuter = function (opts) {
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// trying to find the best balance of an immutable copy with custom attributes
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var jwk = {};
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Object.keys(opts.jwk).forEach(function (k) {
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if ('undefined' === typeof opts.jwk[k]) { return; }
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// ignore EC private parts
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if ('d' === k) { return; }
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jwk[k] = JSON.parse(JSON.stringify(opts.jwk[k]));
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});
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return jwk;
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};
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// https://stackoverflow.com/questions/42588786/how-to-fingerprint-a-jwk
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EC.__thumbprint = function (jwk) {
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// Use the same entropy for SHA as for key
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var alg = 'SHA-256';
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if (/384/.test(jwk.crv)) {
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alg = 'SHA-384';
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}
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return window.crypto.subtle.digest(
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{ name: alg }
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, textEncoder.encode('{"crv":"' + jwk.crv + '","kty":"EC","x":"' + jwk.x + '","y":"' + jwk.y + '"}')
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).then(function (hash) {
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return Enc.bufToUrlBase64(new Uint8Array(hash));
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});
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};
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EC.thumbprint = function (opts) {
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return Promise.resolve().then(function () {
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var jwk;
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if ('EC' === opts.kty) {
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jwk = opts;
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} else if (opts.jwk) {
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jwk = opts.jwk;
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} else {
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return EC.import(opts).then(function (jwk) {
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return EC.__thumbprint(jwk);
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});
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}
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return EC.__thumbprint(jwk);
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});
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};
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Enc.bufToUrlBase64 = function (u8) {
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return Enc.bufToBase64(u8)
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.replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');
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};
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Enc.bufToBase64 = function (u8) {
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var bin = '';
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u8.forEach(function (i) {
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bin += String.fromCharCode(i);
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});
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return btoa(bin);
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};
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}('undefined' !== typeof module ? module.exports : window));
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