KeePass Password Safe is a free open source password manager, which helps you to manage your passwords in a secure way. You can put all your passwords in one database, which is locked with one master key or a key file. So you only have to remember one single master password or select the key file to unlock the whole database. The databases are encrypted using the best and most secure encryption algorithms currently known (AES and Twofish). For more information, see the features page.

Is it really free?
Yes, KeePass is really free, and more than that: it is open source (OSI certified). You can have a look at its full source and check whether the encryption algorithms are implemented correctly.

KeePass Features
* Strong Security
* Multiple User Keys
* Portable and No Installation Required
* Export To TXT, HTML, XML and CSV Files
* Import From Many File Formats
* Easy Database Transfer
* Support of Password Groups
* Time Fields and Entry Attachments
* Auto-Type, Global Auto-Type Hot Key and Drag&Drop
* Intuitive and Secure Clipboard Handling
* Searching and Sorting
* Multi-Language Support
* Strong Random Password Generator
* Plugin Architecture
* Open Source!

Strong Security
* KeePass supports the Advanced Encryption Standard (AES, Rijndael) and the Twofish algorithms to encrypt its password databases.
* Both of these ciphers are regarded as very secure by the cryptography community. Banks are using these algorithms for example, too.
* Even if you would use all computers in the world to attack one database, decrypting it would take longer than the age of the universe.
* Even quantum computers won't help that much. The algorithms are symmetric so its complexity would be reduced a bit, anyway, the sun will go nova before you have decrypted the database.
* The complete database is encrypted, not only the password fields. So your usernames, notes, etc. are protected, too.
* SHA-256 is used as password hash. SHA-256 is a 256-bit cryptographically secure one-way hash function. Your master password is hashed using this algorithm and its output is used as key for the encryption algorithms.
* In contrast to many other hashing algorithms, no attacks are known yet against SHA-256.
* Protection against dictionary and guessing attacks: by transforming the final master key very often, dictionary and guessing attacks can be made harder.
* In-Memory Passwords Protection: Your passwords are encrypted while KeePass is running, so even when the operating system caches the KeePass process to disk, this wouldn't reveal your passwords anyway.
* [2.x] Protected In-Memory Streams: When loading the inner XML format, passwords are encrypted using a session key.
* Security-Enhanced Password Edit Controls: KeePass is the first password manager that features security-enhanced password edit controls. None of the available password edit control spies work against these controls. The passwords entered in those controls aren't even visible in the process memory of KeePass.
* Also see the security information page.

Installation
Download this package and unpack it to your favorite location (USB stick, ...). KeePass runs without any additional installation and won't store any settings outside the application directory.

Supported operating systems:
Windows 98 / 98SE / ME / 2000 / XP / 2003 / Vista / 7, each 32-bit and 64-bit, Mono (Linux, Mac OS X, BSD, ...).

Prerequisites:
Microsoft .NET Framework > 2.0 (preinstalled on Windows Vista) or Mono 2.6.

KeePass 2.21 has been released 03.02.2013
Changes from 2.20.1 to 2.21:
- NEW FEATURES:
* Generic CSV importer: a group separator can be specified now (for importing group trees).
* Internal data viewer: added hex viewer mode (which is now the default for unknown data types).
* In the 'Show Entries by Tag' menu, the number of entries having a specific tag is now shown right of the tag.
* In the 'Add Tag' menu, a tag is now disabled if all selected entries already have this tag.
* Auto-Type: added support for right modifier keys.
* Added special key codes: {WIN}, {LWIN}, {RWIN}, {APPS}, {NUMPAD0} to {NUMPAD9}.
* Interleaved sending of keys is now prevented by default (if you e.g. have an auto-type sequence that triggers another auto-type, enable the new option 'Allow interleaved sending of keys' in 'Tools' -> 'Options' -> tab 'Advanced').
* Added '-auto-type-selected' command line option (other running KeePass instances perform auto-type for the currently selected entry).
* Added option to additionally show references when showing dereferenced data (enabled by default).
* The selection in a secure edit control is now preserved when unhiding and hiding the content.
* The auto-type association editing dialog now does not hang anymore when a window of any other application hangs.
* When an application switches from the secure desktop to a different desktop, KeePass now shows a warning message box; clicking [OK] switches back to the secure desktop.
* Added 'OK'/'Cancel' buttons in the icon picker dialog.
* Added support for importing LastPass 2.0.2 CSV files.
* KeePass now shows an error message when the user accidentally attempts to use a database file as key file.
* Added support for UTF-16 surrogate pairs.
* Added UTF-8 BOM support for version information files.
* The KeePass version is now also shown in the components list in the 'About' dialog.
* File operations are now context-independent (this e.g. makes it possible to use the 'Activate database' trigger action during locking).
* Plugins can now register their placeholders to be shown in the auto-type item editing dialog.
* Plugins can now subscribe to IO access events.
* Added workaround for .NET bug 694242; status dialogs now scale properly with the DPI resolution.
* Added workaround for Mono DataGridView.EditMode bug.
* Added workaround for Mono bug 586901; high Unicode characters in rich text boxes are displayed properly now.
- IMPROVEMENTS / CHANGES:
* When the main window UI is being unblocked, the focus is not reset anymore, if a primary control has the focus.
* When opening the icon picker dialog, KeePass now ensures that the currently selected icon is visible.
* Internal data viewer: improved visibility updating.
* The e-mail box icon by default is not inherited by new entries anymore.
* The database is now marked as modified when auto-typing a TAN entry.
* Enhanced AnyPassword importer to additionally support CSV files exported by AnyPassword Pro 1.07.
* Enhanced Password Safe XML importer (KeePass tries to fix the broken XML files exported by Password Safe 3.29 automatically).
* IO credentials can be loaded over IPC now.
* Enhanced user switch detection.
* Even when an exception occurs, temporary files created during KDB exports are now deleted immediately.
* Improved behavior on Unix-like systems when the operating system does not grant KeePass access to the temporary directory.
* Improved critical sections that are not supposed to be re-entered by the same thread.
* Improved secure desktop name generation.
* When a dialog is closed, references within the global client image list to controls (event handlers) are removed now.
* .NET 4.5 is now preferred, if installed.
* PLGX plugins are now preferably compiled using the .NET 4.5 compiler, if KeePass is currently running under the 4.5 CLR.
* Updated KB links.
* Changed naming of translation files.
* The installer now always overwrites the KeePassLibC 1.x support libraries.
* Upgraded installer.
* Various code optimizations.
* Minor other improvements.
- BUGFIXES:
* When locking multiple databases and cancelling a 'Save Changes?' dialog, the UI is now updated correctly.
* '&' characters in dynamic menu texts, in dialog banner texts, in image combobox texts, in text box prompts and in tooltips are now displayed properly.