const crypto = require("crypto"); function decryptString(dataKey, cipherText) { const buffer = decrypt(dataKey, cipherText); if (buffer === null) { return null; } const str = buffer.toString('utf-8'); if (str === 'false') { throw new Error("Could not decrypt string."); } return str; } function decrypt(key, cipherText, ivLength = 13) { if (cipherText === null) { return null; } if (!key) { return "[protected]"; } try { const cipherTextBufferWithIv = Buffer.from(cipherText.toString(), 'base64'); const iv = cipherTextBufferWithIv.slice(0, ivLength); const cipherTextBuffer = cipherTextBufferWithIv.slice(ivLength); const decipher = crypto.createDecipheriv('aes-128-cbc', pad(key), pad(iv)); const decryptedBytes = Buffer.concat([decipher.update(cipherTextBuffer), decipher.final()]); const digest = decryptedBytes.slice(0, 4); const payload = decryptedBytes.slice(4); const computedDigest = shaArray(payload).slice(0, 4); if (!arraysIdentical(digest, computedDigest)) { return false; } return payload; } catch (e) { // recovery from https://github.com/zadam/trilium/issues/510 if (e.message?.includes("WRONG_FINAL_BLOCK_LENGTH") || e.message?.includes("wrong final block length")) { log.info("Caught WRONG_FINAL_BLOCK_LENGTH, returning cipherText instead"); return cipherText; } else { throw e; } } } function pad(data) { if (data.length > 16) { data = data.slice(0, 16); } else if (data.length < 16) { const zeros = Array(16 - data.length).fill(0); data = Buffer.concat([data, Buffer.from(zeros)]); } return Buffer.from(data); } function arraysIdentical(a, b) { let i = a.length; if (i !== b.length) return false; while (i--) { if (a[i] !== b[i]) return false; } return true; } function shaArray(content) { // we use this as simple checksum and don't rely on its security so SHA-1 is good enough return crypto.createHash('sha1').update(content).digest(); } module.exports = { decrypt, decryptString };