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I was looking for an encryption/decryption tool with a very simple GUI that is available on all platforms (including mobile phones) and uses an open format so that I can decrypt my file via other standard tools too. Another key requirement was that I had to trust the tool.

The main use case was the protection of those few files I do not want to upload to a cloud drive unencrypted.

Having checked and discarded multiple Android apps, I ended up writing a tool on my own. Please find it here:


It is just an HTML file with JavaScript, your browser runs it on the client side only, it does not upload anything anywhere. Actually, it is just a very simple wrapper for the CryptoJS library. Whatever I encrypt can be decrypted with an equivalent OpenSSL command. I used it on files ~10 megabytes, anything bigger should not be handled in a browser.

Feel free to use it! :)


The corresponding entry in Hungarian...


This is my personal website, opinions expressed here are strictly my own, and do not reflect the opinion of my employer. My English blog is experimental and only a small portion of my Hungarian blog is available in English. Contents of my blog may be freely used according to Creative Commons license CC BY.