Picocrypt is a very small (hence Pico), very simple, yet very secure encryption tool that you can use to protect your files. It's designed to be the go-to tool for encryption, with a focus on security, simplicity, and reliability. Picocrypt uses the secure XChaCha20 cipher and the Argon2id key derivation function to provide a high level of security, even from three-letter agencies like the NSA. Your privacy and security is under attack. Take it back with confidence by protecting your files with Picocrypt.

Project status: temporarily on hold. I've decided to take some time off of Picocrypt to focus on my academics and personal goals. Thus, don't expect any new developments for the next little while, although none should be needed as Picocrypt is already very stable and usable. It's been a pleasure developing this app so far and I hope to continue in the future when I have more time and energy. Until then, farewell!

Funding

Please donate to Picocrypt on Open Collective (crypto is accepted) to raise money for a security audit from Cure53. Because this is a project that I spend many hours on and make no money from, I cannot pay for an audit myself. Picocrypt needs support from its community.

Downloads

Important: There are multiple entities under the name "Picocrypt". For example, there's an old encryption tool called PicoCrypt that uses a broken cipher. There's also an ERC-funded research project called PICOCRYPT. There are even domains related to Picocrypt that I've never registered. Please don't confuse any of these unrelated projects with Picocrypt (this project). Make sure to only download Picocrypt from this repository to ensure that you get the authentic and backdoor-free Picocrypt. When sharing Picocrypt with others, be sure to link to this repository to prevent any confusion.

Windows

Picocrypt for Windows is as simple as it gets. To download the latest, standalone, and portable executable for Windows, click here. If Microsoft Defender or your antivirus flags Picocrypt as a virus, please do your part and submit it as a false positive for the betterment of everyone.

If you use Picocrypt frequently, you can also download the installable version from here, which will install Picocrypt onto your system and add it to your start menu for easy access. The installer also includes extra compatibility helpers, so if the portable executable doesn't work, this likely will.

macOS

Picocrypt for macOS is very simple as well. Download Picocrypt here, extract the zip file, and run Picocrypt which is inside. If you can't open Picocrypt because it's not from a verified developer, control-click on Picocrypt and hit Open to bypass the warning. Keep in mind that Picocrypt runs through Rosetta 2 and requires OpenGL, and may not work in the future should Apple remove either.

Linux

To use Picocrypt on Linux, you can download the AppImage here. While this AppImage should work on most systems, Linux is a mess when it comes to cross-distro and cross-release compatibility, so if the AppImage doesn't work, you can try the Snap, run Picocrypt through Wine, or compile from source using the instructions in the src/ directory.

Web

A web interface for Picocrypt is available here, allowing you to use a lite version of Picocrypt on any device. Keep in mind that its functionality is very limited and you won't be able to use any advanced features. It is also quite slow compared to the native app.

CLI

A command-line interface is available for Picocrypt here. Keep in mind that the functionality is extremely limited and is not meant to replace the standard GUI app. Rather, it's best suited for environments where the GUI won't run or you need the ability to automate encryption workflows.

Paranoid Pack

The Paranoid Pack is a compressed archive that contains executables for Windows, macOS, and Linux, including the source code and dependencies. As long as you have it stored in a place you can access, you'll be able to open it and use Picocrypt on any desktop operating system in case this repository mysteriously vanishes or the entire Internet burns down. Think of it as a seed vault for Picocrypt; as long as one person has the Paranoid Pack within reach, they can share it with the rest of the world and keep Picocrypt functional in case of catastrophic events. The best way to ensure Picocrypt is accessible many decades from now is to keep a Paranoid Pack in a safe place. Get your copy here.

Why Picocrypt?

Why should you use Picocrypt instead of VeraCrypt, 7-Zip, BitLocker, or Cryptomator? Here are a few reasons why you should choose Picocrypt:

• Unlike BitLocker and most cloud services, Picocrypt and its dependencies are completely open-source and auditable. You can verify for yourself that there aren't any backdoors or flaws.
• Picocrypt is tiny. While Cryptomator is over 50 MiB and VeraCrypt is over 20 MiB, Picocrypt sits at just 3 MiB, about the size of a medium-resolution photo. And that's not all - Picocrypt is portable (doesn't need to be installed) and doesn't require administrator/root privileges.
• Picocrypt is easier and more productive to use than VeraCrypt. To encrypt files with VeraCrypt, you'd have to spend a minute or two just setting up a volume. With Picocrypt's simple UI, all you have to do is drag and drop your files, enter a password, and hit Encrypt. All the complex procedures are handled by Picocrypt internally. Who said secure encryption can't be simple?
• Picocrypt is designed for security. 7-Zip is an archive utility and not an encryption tool, so its focus is not on security. Picocrypt, however, is built with security as the number one priority. Every part of Picocrypt exists for a reason and anything that could impact the security of Picocrypt is removed. Picocrypt is built with cryptography you can trust.
• Picocrypt authenticates data in addition to protecting it, preventing hackers from maliciously modifying sensitive data. This is useful when you are sending encrypted files over an insecure channel and want to be sure that it arrives untouched.
• Picocrypt actively protects header data from corruption by adding extra Reed-Solomon parity bytes, so if part of a volume's header (which contains important cryptographic components) corrupts (e.g., hard drive bit rot), Picocrypt can still recover the header and decrypt your data with a high success rate. Picocrypt can also encode the entire volume with Reed-Solomon to prevent any corruption to your important files.

Comparison

Here's how Picocrypt compares to other popular encryption tools.

	Picocrypt	VeraCrypt	7-Zip GUI	BitLocker	Cryptomator
Free	✅ Yes	✅ Yes	✅ Yes	✅ Bundled	✅ Yes
Open Source	✅ GPLv3	✅ Multi	✅ LGPL	❌ No	✅ GPLv3
Cross-Platform	✅ Yes	✅ Yes	❌ No	❌ No	✅ Yes
Size	✅ 3 MiB	❌ 20 MiB	✅ 2 MiB	✅ N/A	❌ 50 MiB
Portable	✅ Yes	✅ Yes	❌ No	✅ Yes	❌ No
Permissions	✅ None	❌ Admin	❌ Admin	❌ Admin	❌ Admin
Ease-Of-Use	✅ Easy	❌ Hard	✅ Easy	✅ Easy	🟧 Medium
Cipher	✅ XChaCha20	✅ AES-256	✅ AES-256	🟧 AES-128	✅ AES-256
Key Derivation	✅ Argon2	🟧 PBKDF2	❌ SHA-256	❓ Unknown	✅ Scrypt
Data Integrity	✅ Always	❌ No	❌ No	❓ Unknown	✅ Always
Deniability	✅ Supported	✅ Supported	❌ No	❌ No	❌ No
Reed-Solomon	✅ Yes	❌ No	❌ No	❌ No	❌ No
Compression	✅ Yes	❌ No	✅ Yes	✅ Yes	❌ No
Telemetry	✅ None	✅ None	✅ None	❓ Unknown	✅ None
Audited	🟧 Planned	✅ Yes	❌ No	❓ Unknown	✅ Yes

Keep in mind that while Picocrypt does most things better than other tools, it's not a one-size-fits-all and doesn't try to be. There are use cases such as full-disk encryption where VeraCrypt and BitLocker would be a better choice. So while Picocrypt is a great choice for the majority of people, you should still do your own research and use what's best for you.

Features

Picocrypt is a very simple tool, and most users will intuitively understand how to use it in a few seconds. On a basic level, simply dropping your files, entering a password, and hitting Encrypt is all that's needed to encrypt your files. Dropping the output back into Picocrypt, entering the password, and hitting Decrypt is all that's needed to decrypt those files. Pretty simple, right?

While being simple, Picocrypt also strives to be powerful in the hands of knowledgeable and advanced users. Thus, there are some additional options that you may use to suit your needs.

• Password generator: Picocrypt provides a secure password generator that you can use to create cryptographically secure passwords. You can customize the password length, as well as the types of characters to include.
• Comments: Use this to store notes, information, and text along with the file (it won't be encrypted). For example, you can put a description of the file you're encrypting before sending it to someone. When the person you sent it to drops the file into Picocrypt, your description will be shown to that person.
• Keyfiles: Picocrypt supports the use of keyfiles as an additional form of authentication (or the only form of authentication). Any file can be used as a keyfile, and a secure keyfile generator is provided for convenience. Not only can you use multiple keyfiles, but you can also require the correct order of keyfiles to be present for a successful decryption to occur. A particularly good use case of multiple keyfiles is creating a shared volume, where each person holds a keyfile, and all of them (and their keyfiles) must be present to decrypt the shared volume. By checking the "Require correct order" box and dropping your keyfile in last, you can also ensure that you'll always be the one clicking the Decrypt button.
• Paranoid mode: Using this mode will encrypt your data with both XChaCha20 and Serpent in a cascade fashion, and use HMAC-SHA3 to authenticate data instead of BLAKE2b. Argon2 parameters will be increased significantly as well. This is recommended for protecting top-secret files and provides the highest level of practical security attainable. For a hacker to break into your encrypted data, both the XChaCha20 cipher and the Serpent cipher must be broken, assuming you've chosen a good password. It's safe to say that in this mode, your files are impossible to crack. Keep in mind, however, that this mode is slower and isn't really necessary unless you're a government agent with classified data or a whistleblower under threat.
• Reed-Solomon: This feature is very useful if you are planning to archive important data on a cloud provider or external medium for a long time. If checked, Picocrypt will use the Reed-Solomon error correction code to add 8 extra bytes for every 128 bytes of data to prevent file corruption. This means that up to ~3% of your file can corrupt and Picocrypt will still be able to correct the errors and decrypt your files with no corruption. Of course, if your file corrupts very badly (e.g., you dropped your hard drive), Picocrypt won't be able to fully recover your files, but it will try its best to recover what it can. Note that this option will slow down encryption and decryption speeds significantly.
• Force decrypt: Picocrypt automatically checks for file integrity upon decryption. If the file has been modified or is corrupted, Picocrypt will automatically delete the output for the user's safety. If you would like to override these safeguards, check this option. Also, if this option is checked and the Reed-Solomon feature was used on the encrypted volume, Picocrypt will attempt to recover as much of the file as possible during decryption.
• Split into chunks: Don't feel like dealing with gargantuan files? No worries! With Picocrypt, you can choose to split your output file into custom-sized chunks, so large files can become more manageable and easier to upload to cloud providers. Simply choose a unit (KiB, MiB, GiB, or TiB) and enter your desired chunk size for that unit. To decrypt the chunks, simply drag one of them into Picocrypt and the chunks will be automatically recombined during decryption.
• Compress files: By default, Picocrypt uses a zip file with no compression to quickly merge files together when encrypting multiple files. If you would like to compress these files, however, simply check this box and the standard Deflate compression algorithm will be applied during encryption.
• Deniability: Picocrypt volumes typically follow an easily recognizable header format. However, if you want to hide the fact that you are encrypting your files, enabling this option will provide you with plausible deniability. The output volume will indistinguishable from a stream of random bytes, and no one can prove it is a volume without the correct password. This can be useful in an authoritarian country where the only way to transport your files safely is if they don't "exist" in the first place. Keep in mind that this mode slows down encryption and decryption speeds, requires you to manually rename the volume afterward, renders comments useless, and also voids the extra security precautions of the paranoid mode, so you should only use it if absolutely necessary.
• Recursively: If you want to encrypt and/or decrypt a large set of files individually, this option will tell Picocrypt to go through every recursive file that you drop in and encrypt/decrypt it separately. This is useful, for example, if you are encrypting thousands of large documents and want to be able to decrypt any one of them in particular without having to download and decrypt the entire set of documents. Keep in mind that this is a very complex feature that should only be used if you know what you are doing.

Security

For more information on how Picocrypt handles cryptography, see Internals for the technical details. If you're worried about the safety of me or this project, let me assure you that this repository won't be hijacked or backdoored. I have 2FA (TOTP) enabled on all accounts with a tie to Picocrypt (GitHub, Reddit, Google, etc.), in addition to full-disk encryption on all of my portable devices. For further hardening, Picocrypt uses my isolated forks of dependencies and I fetch upstream only when I have taken a look at the changes and believe that there aren't any security issues. This means that if a dependency gets hacked or deleted by the author, Picocrypt will be using my fork of it and remain completely unaffected. You can feel confident about using Picocrypt.

Signatures

For the paranoid, Picocrypt is signed with PGP. The fingerprint and public key are listed below.

B342A744BDEEA57B6A583E33A247E73798946F55

-----BEGIN PGP PUBLIC KEY BLOCK-----

mDMEYoGUHxYJKwYBBAHaRw8BAQdAvmQA+pdbDB/ynJxHhNDpz6Sb5tgkNuuNJIvw
HYwZtqi0CVBpY29jcnlwdIiTBBMWCgA7FiEEs0KnRL3upXtqWD4zokfnN5iUb1UF
AmKBlB8CGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgkQokfnN5iUb1UZ
RgEA8jbIsdqCr21DWxcqW/eLlbxRkuA8kflVYvWWUxtVqsUA/jQPSDpvA8rakvaL
PIbXjQvrAMkEVIc0HbCzLxr1k3sH
=YFwz
-----END PGP PUBLIC KEY BLOCK-----

Community

Keep an eye on r/Picocrypt. While I won't be active in this subreddit myself, it's still a great place to ask questions and help one another out, especially if something happens to me or this repository in the future. Remember to only trust this specific subreddit and be aware of hackers that might try to impersonate me on other platforms. I will never ask you for your password, and anyone who does is not me. I will never tell you to download a file from a suspicious link, and anyone who does is not me.

Donations

When I was actively developing Picocrypt, I accepted donations, but now that Picocrypt is complete and production-ready, there's no need anymore. Instead, take your time and effort to share the love of Picocrypt with others. Donations are nice, but being able to help others is a lot more valuable to me than a few spare dollars. Knowing that Picocrypt is helping people secure their files is plenty enough for me.

FAQ

Is Picocrypt accepting new features?

No, Picocrypt is considered feature-complete and won't be getting any new features. Unlike other tools which try to constantly add new features (which introduces new bugs and security holes), Picocrypt focuses on just a few core features but does each of them exceptionally well. Remember Picocrypt's ideology: small, simple, and secure.

Will Android/iOS be supported?

No, I don't plan on supporting Android or iOS because they are very different from traditional desktop operating systems and require different toolchains to develop apps for. Due to the nature of open-source software, however, a community-built version of Picocrypt for Android or iOS may appear in the future.

Why is Picocrypt not updated frequently?

People seem to have the notion that software must be constantly updated to stay relevant and secure. While this may be true for a lot of the software we use today, it is not for Picocrypt. Picocrypt is "good software" and good software doesn't need constant updates to remain relevant and secure. Good software will always be good software.

Does the "Delete files" feature shred files?

No, it doesn't shred any files and just deletes them as your file manager would. On modern storage mediums like SSDs, there is no such thing as shredding a file since wear leveling makes it impossible to overwrite a particular sector. Thus, to prevent giving users a false sense of security, Picocrypt doesn't include any shredding features at all.

Is Picocrypt quantum-secure?

Yes, Picocrypt is secure against quantum computers. All of the cryptography used in Picocrypt works off of a private key, and private-key cryptography is considered to be resistant against all current and future developments, including quantum computers.

Acknowledgements

A thank you from the bottom of my heart to the significant contributors on Open Collective:

• donor39 (backer)
• Pokabu (backer)
• akp (backer)
• Marvin (backer)
• Kenichi Nakasaka (backer)
• Guest ($842)
• YellowNight ($818)
• evelian ($50)
• jp26 ($50)
• guest-116103ad ($50)
• Guest ($27)
• oli ($20)
• Bright ($20)
• Markus ($15)
• Tybbs ($10)
• N. Chin ($10)
• Manjot ($10)
• Phil P. ($10)
• Raymond ($10)
• Cohen ($10)
• EuA ($10)
• geevade ($10)
• Guest ($10)
• Hilebrinest ($10)
• gabu.gu ($10)
• Boat ($10)

Also, a huge thanks to the following people who were the first to donate and support Picocrypt:

• W.Graham
• N. Chin
• Manjot
• Phil P.
• E. Zahard

Finally, thanks to these people/organizations for helping me out when needed:

• [ REDACTED ] for helping me create an AppImage for Picocrypt
• u/Upstairs-Fishing867 for helping me test PGP signatures
• u/greenreddits for constant feedback and support
• u/Tall_Escape for helping me test Picocrypt
• u/NSABackdoors for doing plenty of testing
• @samuel-lucas6 for feedback, suggestions, and support
• @AsuxAX and @Minibus93 for testing new features
• @mdanish-kh and @stephengillie for WinGet package
• PrivacyGuides for listing Picocrypt