JSEncrypt

1.0.4 verified Sat Apr 25 auth: no javascript

JSEncrypt for node & browser. Version 1.0.4 provides RSA encryption/decryption using the JSEncrypt library, compatible with both Node.js and browser environments. It is a fork of the original JSEncrypt by Apipost. The library allows setting public/private keys in PEM format and uses the RSA algorithm. It is suitable for basic RSA operations but note it is a thin wrapper around the original JSEncrypt. No recent updates; release cadence is low.

Common errors

error Error: JSEncrypt is not a constructor ↓

cause Using CommonJS require without .default

fix

Use const JSEncrypt = require('jsencrypt-node').default;

error TypeError: this.key is undefined ↓

cause setPublicKey or setPrivateKey called with invalid PEM or not called at all

fix

Ensure the PEM string is correct and includes BEGIN/END lines with no extra whitespace.

error false ↓

cause Decrypt method returns false when decryption fails (e.g., wrong key, corrupted ciphertext)

fix

Verify the key matches the encryption key and the ciphertext is valid Base64.

Warnings

gotcha Private key must be in PKCS#1 PEM format (RSA PRIVATE KEY), not PKCS#8 (PRIVATE KEY). ↓

fix Convert PKCS#8 keys to PKCS#1 using openssl rsa -in key.pem -out pkcs1.pem

gotcha Decrypt method may return false if the encrypted string is invalid or key does not match. ↓

fix Check the return value: if (decrypted === false) { /* handle error */ }

gotcha Encrypted output is Base64-encoded, not raw binary. Do not assume hex. ↓

fix Use ciphertext as-is for Base64; if you need hex, convert via Buffer.

Install

npm install jsencrypt-node

yarn add jsencrypt-node

pnpm add jsencrypt-node

Imports

JSEncrypt

wrong

const JSEncrypt = require('jsencrypt-node')

correct

import JSEncrypt from 'jsencrypt-node'

ESM default import works; CommonJS requires default import style.

JSEncrypt

wrong

const JSEncrypt = require('jsencrypt-node')

correct

const JSEncrypt = require('jsencrypt-node').default

In CommonJS, default export is under .default.

JSEncrypt

const { JSEncrypt } = require('jsencrypt-node')

Named export works in CommonJS.

Quickstart

Demonstrates RSA encryption and decryption using JSEncrypt with public and private PEM keys.

import JSEncrypt from 'jsencrypt-node';

const encrypt = new JSEncrypt();
encrypt.setPublicKey('-----BEGIN PUBLIC KEY-----MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC1QQRl0HlrVv6kGqhgonD6A9SU6ZJpnEN+Q0blT/ue6Ndt97WRfxtSAs0QoquTreaDtfC4RRX4o+CU6BTuHLUm+eSvxZS9TzbwoYZq7ObbQAZAY+SYDgAA5PHf1wNN20dGMFFgVS/y0ZWvv1UNa2laEz0I8Vmr5ZlzIn88GkmSiQIDAQAB-----END PUBLIC KEY-----');
const cipher = encrypt.encrypt('Hello, world!');
console.log(cipher);

const decrypt = new JSEncrypt();
decrypt.setPrivateKey('-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----');
const plain = decrypt.decrypt(cipher);
console.log(plain);