computer science

TrueCrypt

TrueCrypt is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand TrueCrypt rather than just read about it. In short: TrueCrypt is a discontinued source-available freeware utility used for on-the-fly encryption (OTFE). It can create a virtual encrypted disk within a file, encrypt a partition, or encrypt the whole storage device (pre-boot authentication).

Key takeaways

TrueCrypt 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 TrueCrypt to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of TrueCrypt from memory before moving on to harder problems.

Reference excerpt

TrueCrypt is a discontinued source-available freeware utility used for on-the-fly encryption (OTFE). It can create a virtual encrypted disk within a file, encrypt a partition, or encrypt the whole storage device (pre-boot authentication). On 28 May 2014, the TrueCrypt website announced that the project was no longer maintained and recommended users find alternative solutions. Though development of TrueCrypt has ceased, an independent audit of TrueCrypt published in March 2015 concluded that no significant flaws were present. Two projects forked from TrueCrypt: VeraCrypt (active) and CipherShed (abandoned).

History

TrueCrypt was initially released as version 1.0 in February 2004, based on E4M (Encryption for the Masses). Several versions and many additional minor releases have been made since then, with the most current version being 7.1a.

E4M and SecurStar dispute Original release of TrueCrypt was made by anonymous developers called "the TrueCrypt Team". Shortly after version 1.0 was released in 2004, the TrueCrypt Team reported receiving email from Wilfried Hafner, manager of SecurStar, a computer security company. According to the TrueCrypt Team, Hafner claimed in the email that the acknowledged author of E4M, developer Paul Le Roux, had stolen the source code from SecurStar as an employee. It was further stated that Le Roux illegally distributed E4M, and authored an illegal license permitting anyone to base derivative work on the code and distribute it freely. Hafner alleges all versions of E4M always belonged only to SecurStar, and Le Roux did not have any right to release it under such a license. This led the TrueCrypt Team to immediately stop developing and distributing TrueCrypt, which they announced online through usenet. TrueCrypt Team member David Tesařík stated that Le Roux informed the team that there was a legal dispute between himself and SecurStar, and that he received legal advisement not to comment on any issues of the case. Tesařík concluded that should the TrueCrypt Team continue distributing TrueCrypt, Le Roux may ultimately be held liable and be forced to pay consequent damages to SecurStar. To continue in good faith, he said, the team would need to verify the validity of the E4M license. However, because of Le Roux's need to remain silent on the matter, he was unable to confirm or deny its legitimacy, keeping TrueCrypt development in limbo. Thereafter, would-be visitors reported trouble accessing the TrueCrypt website, and third-party mirrors appeared online making the source code and installer continually available, outside of official sanction by the TrueCrypt Team. In the FAQ section of its website, SecurStar maintains its claims of ownership over both E4M and Scramdisk, another free encryption program. The company states that with those products, SecurStar "had a long tradition of open source software", but that "competitors had nothing better to do but to steal our source code", causing the company to make its products closed-source, forcing potential customers to place a substantial order and sign a non-disclosure agreement before being allowed to review the code for security. Le Roux himself has denied developing TrueCrypt in a court hearing in March 2016, in which he also confirmed he had written E4M.

Version 2.0 Months later on 7 June 2004, TrueCrypt 2.0 was released. The new version contained a different digital signature from that of the original TrueCrypt Team, with the developers now being referred to as "the TrueCrypt Foundation." The software license was also changed to the open source GNU General Public License (GPL). However, given the wide range of components with differing licenses making up the software, and the contested nature of the legality of the program's release, a few weeks later on 21 June, version 2.1 was released under the original E4M license to avoid potential problems relating to the GPL license. Version 2.1a of the software was released on 1 October 2004 on truecrypt.sourceforge.net subdomain. By May 2005, the original TrueCrypt website returned and truecrypt.sourceforge.net redirected visitors to truecrypt.org.

End of life announcement On 28 May 2014, the TrueCrypt official website, truecrypt.org, began redirecting visitors to truecrypt.sourceforge.net with a HTTP 301 "Moved Permanently" status, which warned that the software may contain unfixed security issues, and that development of TrueCrypt was discontinued in May 2014, following Windows XP's end of support. The message noted that more recent versions of Windows have built-in support for disk encryption using BitLocker, and that Linux and OS X had similar built-in solutions, which the message states renders TrueCrypt unnecessary. The page recommends any data encrypted by TrueCrypt be migrated to other encryption setups and offered instructions on moving to BitLocker. The SourceForge project page for the software at sourceforge.net/truecrypt was updated to display the same initial message, and the status was changed to "inactive". The page also announced a new software version, 7.2, which only allows decryption. Initially, the authenticity of the announcement and new software was questioned. Multiple theories attempting to explain the reason behind the announcement arose throughout the tech community. Shortly after the end of life announcement of TrueCrypt, Gibson Research Corporation posted an announcement titled "Yes... TrueCrypt is still safe to use" and a final release repository to host the last official non-crippled version 7.1a of TrueCrypt. They no longer host the final release repository as of 2022.

Operating systems TrueCrypt supports Windows, OS X, and Linux operating systems. Both 32-bit and 64-bit versions of these operating systems are supported, except for Windows IA-64 (not supported) and Mac OS X 10.6 Snow Leopard (runs as a 32-bit process). The version for Windows 7, Windows Vista, and Windows XP can encrypt the boot partition or entire boot drive.

Independent implementations There is an independent, compatible implementation, tcplay, for DragonFly BSD and Linux. The dm-crypt module included in the default Linux kernel supports a TrueCrypt target called "tcw" since Linux version 3.13.

Encryption scheme

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with TrueCrypt

Start with the simplest possible case. Write down what TrueCrypt 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 TrueCrypt 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 TrueCrypt 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 TrueCrypt

In research: TrueCrypt 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 TrueCrypt 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: TrueCrypt is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2004 software, Cross-platform software, Cryptographic software, so understanding it makes those chapters shorter.
In everyday life: Look for TrueCrypt 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.

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How to study TrueCrypt in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what TrueCrypt 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 TrueCrypt out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is TrueCrypt in simple terms?

Why does TrueCrypt 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 TrueCrypt?

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 TrueCrypt.