Nitrokey

Key takeaways

Nitrokey belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nitrokey to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nitrokey from memory before moving on to harder problems.

Reference excerpt

Nitrokey is an open-source USB key used to enable the secure encryption and signing of data. The secret keys are always stored inside the Nitrokey which protects against malware (such as computer viruses) and attackers. A user-chosen PIN and a tamper-proof smart card protect the Nitrokey in case of loss and theft. The hardware and software of Nitrokey are open-source. The free software and open hardware enables independent parties to verify the security of the device. Nitrokey is supported on Microsoft Windows, macOS, Linux, and BSD.

History In 2008 Jan Suhr, Rudolf Böddeker, and another friend were travelling and found themselves looking to use encrypted emails in internet cafés, which meant the secret keys had to remain secure against computer viruses. Some proprietary USB dongles existed at the time, but lacked in certain ways. Consequently, they established as an open source project - Crypto Stick - in August 2008 which grew to become Nitrokey. It was a spare-time project of the founders to develop a hardware solution to enable the secure usage of email encryption. The first version of the Crypto Stick was released on 27 December 2009. In late 2014, the founders decided to professionalize the project, which was renamed Nitrokey. Nitrokey's firmware was audited by German cybersecurity firm Cure53 in May 2015, and its hardware was audited by the same company in August 2015. The first four Nitrokey models became available on 18 September 2015.

Technical features Several Nitrokey models exist which each support different standards. For reference S/MIME is an email encryption standard popular with businesses while OpenPGP can be used to encrypt emails and also certificates used to login to servers with OpenVPN or OpenSSH. One-time passwords are similar to TANs and used as a secondary security measure in addition to ordinary passwords. Nitrokey supports the HMAC-based One-time Password Algorithm (HOTP, RFC 4226) and Time-based One-time Password Algorithm (TOTP, RFC 6238), which are compatible with Google Authenticator.

The Nitrokey Storage product has the same features as the Nitrokey Pro 2 and additionally contains an encrypted mass storage.

Characteristics Nitrokey's devices store secret keys internally. As with earlier technologies including the trusted platform module they are not readable on demand. This reduces the likelihood of a private key being accidentally leaked which is a risk with software-based public key cryptography. The keys stored in this way are also not known to the manufacturer. Supported algorithms include AES-256 and RSA with key lengths of up to 2048 bits or 4096 bits depending on the model. For accounts that accept Nitrokey credentials, a user-chosen PIN can be used to protect these against unauthorized access in case of loss or theft. However, loss of or damage to a Nitrokey (which is designed to last for 5–10 years) can also prevent the key's owner from being able to access their accounts. To guard against this, it is possible to generate keys in software so that they may be securely backed up to the best of the user's ability before they undergo a one-way transfer to the secure storage of a Nitrokey. Nitrokey is published as open source software and free software which ensures a wide range of cross platform support including Microsoft Windows, macOS, Linux, and BSD. It is designed to be usable with popular software such as Microsoft Outlook, Mozilla Thunderbird, and OpenSSH. It is also open hardware to enable independent reviews of the source code and hardware layout and to ensure the absence of back doors and other security flaws.

Philosophy Nitrokey's developers believe that proprietary systems cannot provide strong security and that security systems need to be open source. For instance there have been cases in which the NSA has intercepted security devices being shipped and implanted backdoors into them. In 2011 RSA was hacked and secret keys of securID tokens were stolen which allowed hackers to circumvent their authentication. As revealed in 2010, many FIPS 140-2 Level 2 certified USB storage devices from various manufacturers could easily be cracked by using a default password. Nitrokey, because it is open source and transparent, wants to provide a highly secure system and avoid security issues which its proprietary rivals are facing. Nitrokey's mission is to provide the best open source security key to protect the digital lives of its users.

References

External links Official website

Worked examples

Example 1 — a first encounter with Nitrokey

Start with the simplest possible case. Write down what Nitrokey claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nitrokey before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nitrokey ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nitrokey

In research: Nitrokey appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nitrokey in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nitrokey is common in secondary-school and first-year university syllabi. It links to neighbouring topics Authentication methods, Computer access control, Cryptographic hardware, so understanding it makes those chapters shorter.
In everyday life: Look for Nitrokey outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Nitrokey in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nitrokey means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Nitrokey out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nitrokey in simple terms?

Nitrokey is an open-source USB key used to enable the secure encryption and signing of data. The secret keys are always stored inside the Nitrokey which protects against malware (such as computer viruses) and attackers.

Why does Nitrokey matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nitrokey?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nitrokey.