TrueCrypt 5.1a

TrueCrypt 是一個免費的磁碟加密軟體，支援多種加密演算法例如： Twofish、Serpent 等。

• 目前為 USB 隨身碟等行動裝置的使用普及。
• 此款加密檔案為免費軟體，可隨身攜帶，簡便使用。
• 基本上各種可能需要的加密方法，都可以用 TrueCrypt 來達成。
• 使用 TrueCrypt 可以很方便地保護個人電腦內的機敏資料。
• 內建的加密演算法都是目前密碼學中公認最難以利用暴力法破解，所以使用者也可安心使用。
• 就算不小心檔案被竊取，如果對方沒有經過TrueCrypt軟體的掛載並輸入正確密碼，也是無法讀取您加密區中的任何檔案或文件。

Improvements:
* Faster booting when the system partition/drive is encrypted (typically by 10%). (Windows Vista/XP/2008/2003)
* Other minor improvements. (Windows, Mac OS X, and Linux)

Resolved incompatibilities:
* On computers with certain hardware configurations, resuming from hibernation failed when the system partition was encrypted. Note: If you encountered this problem, the content of RAM may have been saved unencrypted to the hibernation file. You can erase such data, for example, by decrypting the system partition/drive (select System > Permanently Decrypt System Partition/Drive) and then encrypting it again. (Windows Vista/XP/2008/2003)

Remark: As Microsoft does not provide any API for handling hibernation, all non-Microsoft developers of disk encryption software are forced to modify undocumented components of Windows in order to allow users to encrypt hibernation files. Therefore, no disk encryption software (except for Microsoft's BitLocker) can guarantee that hibernation files will always be encrypted. At anytime, Microsoft can arbitrarily modify components of Windows (using the Auto Update feature of Windows) that are not publicly documented or accessible via a public API. Any such change, or the use of an untypical or custom storage device driver, may cause any non-Microsoft disk encryption software to fail to encrypt the hibernation file. We plan to file a complaint with Microsoft (and if rejected, with the European Commission) about this issue, also due to the fact that Microsoft's disk encryption software, BitLocker, is not disadvantaged by this.
* Workaround for a bug in the BIOS of some Apple computers that prevented users from entering pre-boot authentication passwords and controlling the TrueCrypt Boot Loader. (Windows Vista/XP/2008/2003)

Bug fixes:
* When the system partition/drive is decrypted under Windows, the original partition table will not be restored. Note: This issue affected users who repartitioned an encrypted system drive and then decrypted it under Windows. (Windows Vista/XP/2008/2003)
* Other minor bug fixes. (Windows, Mac OS X, and Linux)