39 lines
1.3 KiB
JavaScript
39 lines
1.3 KiB
JavaScript
'use strict';
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const crypto = require('crypto');
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function b64url(input) {
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return Buffer.from(input).toString('base64url');
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}
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function signHS256(payload, secret, expiresInSec = 3600) {
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const now = Math.floor(Date.now() / 1000);
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const body = { ...payload, iat: now, exp: now + expiresInSec };
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const header = b64url(JSON.stringify({ alg: 'HS256', typ: 'JWT' }));
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const claims = b64url(JSON.stringify(body));
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const data = `${header}.${claims}`;
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const sig = crypto.createHmac('sha256', secret).update(data).digest('base64url');
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return `${data}.${sig}`;
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}
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function verifyHS256(token, secret) {
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if (!token || !secret) return null;
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const parts = String(token).split('.');
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if (parts.length !== 3) return null;
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const [header, claims, sig] = parts;
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const expected = crypto.createHmac('sha256', secret).update(`${header}.${claims}`).digest('base64url');
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const a = Buffer.from(sig);
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const b = Buffer.from(expected);
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if (a.length !== b.length || !crypto.timingSafeEqual(a, b)) return null;
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let payload;
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try {
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payload = JSON.parse(Buffer.from(claims, 'base64url').toString('utf8'));
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} catch {
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return null;
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}
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if (payload.exp && payload.exp < Math.floor(Date.now() / 1000)) return null;
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return payload;
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}
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module.exports = { signHS256, verifyHS256 };
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