Скачать или смотреть How to Read Public and Private Keys from Files in Node.js

Learn how to encrypt and decrypt messages in Node.js by effectively reading public and private keys from stored files. Find different solutions to handle PEM and DER formats easily.
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This video is based on the question https://stackoverflow.com/q/64003676/ asked by the user 'Ritvik Joshi' ( https://stackoverflow.com/u/12797819/ ) and on the answer https://stackoverflow.com/a/64006113/ provided by the user 'Michael Fehr' ( https://stackoverflow.com/u/8166854/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Reading Public and Private Keys in Node.js

When working with encryption in Node.js, a common requirement is the ability to read public and private keys from files on your system. This task becomes especially pertinent if you're migrating from another programming language, like Java, where reading keys may be more straightforward. In this guide, we're going to explore how to effectively read these keys in Node.js and address common errors you may encounter, particularly when dealing with different file formats such as PEM and DER.

The Problem at Hand

You've probably encountered an issue while trying to read RSA public and private keys stored in files. In Java, it’s quite simple to read these keys, as demonstrated in the code below:

[[See Video to Reveal this Text or Code Snippet]]

However, when translating this into Node.js, you might find yourself struggling. You attempted to use the built-in crypto module and faced an error while passing the key to the publicEncrypt method:

[[See Video to Reveal this Text or Code Snippet]]

This indicates an issue with the format of the key you're trying to read. Let’s delve into how to fix this.

Understanding Key Formats

The error you're encountering often arises from a mismatch between the formats used in different programming environments. In Java, you might be using a raw byte format, which is incompatible with Node.js's expectations. In Node.js, keys are typically used in PEM format. Here are some ways to handle this:

Adjust the Key Format in Java: Write the keys in a format that Node.js can easily read (PEM).

Create a Converter in Node.js: Implement a method in Node.js to convert the keys into the correct format dynamically.

Use a Tool Like OpenSSL: This is a straightforward approach if you have only a few key pairs to handle.

Solution Using OpenSSL

For many users, the simplest solution is to convert your keys using OpenSSL. Here’s how to do it step-by-step.

Step 1: Convert Your Keys

Assuming you have two files: rsa_privatekey_2048.der and rsa_publickey_2048.der, you can convert these DER files to PEM format using the following commands in your terminal:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Verify Your PEM Keys

Here’s an example of what your converted PEM files might look like:

rsa_privatekey_2048.pem:

[[See Video to Reveal this Text or Code Snippet]]

rsa_publickey_2048.pem:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Reading the Keys in Node.js

Once you've converted your keys to the PEM format, you can read them in Node.js using the following code snippet:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Handling key formats can be a significant stumbling block when transitioning from one programming language to another. The solution involves either adjusting the format directly in Java or using tools like OpenSSL for conversion. With the correct key format in PEM, reading and using public and private keys in Node.js becomes a much smoother process.

If you've followed the steps outlined here, you should now be able to read encrypted messages correctly and perform encryption using your RSA keys.

Feel free to reach out if you have more questions or need further assistance!