Password based file encryption

[naveenkumarsangi]

Reference: https://stackoverflow.com/questions/35449630/how-to-encrypt-file-using-express-multer

[pranay414]

@nkprince007 I would like to up this issue.

[naveenkumarsangi]

Sure, go ahead.

[pranay414]

@nkprince007 can you elaborate this issue?

[naveenkumarsangi]

Sure, multer provides an event onFileUploadComplete which can be configured to our requirement. Once the file upload is done, use any encryptor of your liking (preferably file-encryptor) and encrypt the file with the same name. When user tries to access that resource, you'd need to a password based verification which, on acceptance should be able to download the file.

However, make sure that encryption is only optional and not enforced.

[pranay414]

@nkprince007 I found that event callbacks don't work. Ref: https://stackoverflow.com/questions/32045027/multer-callbacks-not-working. What to do in this case?

[naveenkumarsangi]

Well, in that case we could ditch multer and use some other library like formidable perhaps and write a handler for the /upload route which parses the form POSTed by the frontend dropzone.

Reference: https://gist.github.com/paambaati/db2df71d80f20c10857d#file-upload_demo_nodejs-js

[pranay414]

@nkprince007 can you tell me how will a user download an uploaded file from the server?, btw I have implemented formidable and have encrypted the file successfully. Also is it necessary to store encrypted file in uploads directory and delete the original file after encryption?

[naveenkumarsangi]

Yes, you'd need to delete the original once encryption is done. Actually, for now, I'm serving the entire directory statically instead of a standard download procedure. I'd rather want to proceed with the same thing than writing a download procedure. So, if possible, try to compress the files once uploaded and then use encryption on the zipped file rather than encrypting the file. And it should be possible to manually decrypt the file (offline too) with a password.

[pranay414]

@nkprince007 any references on how to manually decrypt(offline too) with a password. I compressed the files using fs.exec() and then encrypted it as a .dat file, is it ok?

[naveenkumarsangi]

https://stackoverflow.com/questions/14829782/generate-a-password-protected-zip-file-in-node-js