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- var SEA = require('./root');
- var shim = require('./shim');
- var S = require('./settings');
- // Derive shared secret from other's pub and my epub/epriv
- SEA.secret = SEA.secret || (async (key, pair, cb, opt) => { try {
- opt = opt || {};
- if(!pair || !pair.epriv || !pair.epub){
- pair = await SEA.I(null, {what: key, how: 'secret', why: opt.why});
- }
- var pub = key.epub || key;
- var epub = pair.epub;
- var epriv = pair.epriv;
- var ecdhSubtle = shim.ossl || shim.subtle;
- var pubKeyData = keysToEcdhJwk(pub);
- var props = Object.assign({ public: await ecdhSubtle.importKey(...pubKeyData, true, []) },S.ecdh);
- var privKeyData = keysToEcdhJwk(epub, epriv);
- var derived = await ecdhSubtle.importKey(...privKeyData, false, ['deriveKey']).then(async (privKey) => {
- // privateKey scope doesn't leak out from here!
- var derivedKey = await ecdhSubtle.deriveKey(props, privKey, { name: 'AES-GCM', length: 256 }, true, [ 'encrypt', 'decrypt' ]);
- return ecdhSubtle.exportKey('jwk', derivedKey).then(({ k }) => k);
- })
- var r = derived;
- if(cb){ try{ cb(r) }catch(e){console.log(e)} }
- return r;
- } catch(e) {
- console.log(e);
- SEA.err = e;
- if(SEA.throw){ throw e }
- if(cb){ cb() }
- return;
- }});
- // can this be replaced with settings.jwk?
- var keysToEcdhJwk = (pub, d) => { // d === priv
- //var [ x, y ] = Buffer.from(pub, 'base64').toString('utf8').split(':') // old
- var [ x, y ] = pub.split('.') // new
- var jwk = d ? { d: d } : {}
- return [ // Use with spread returned value...
- 'jwk',
- Object.assign(
- jwk,
- { x: x, y: y, kty: 'EC', crv: 'P-256', ext: true }
- ), // ??? refactor
- S.ecdh
- ]
- }
- module.exports = SEA.secret;
-
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