Open source refers to a technology open to the public for use and/or modification from its original design. Open source programming code is available for anyone to review, so there are no surprises in the open source applications or programs you are using. These projects are typically a collaborative effort where programmers improve upon the source code and share the changes within the community so that other members can help improve it further.
The Bitcoin protocol is completely open source and has been since it was first released in 2009. It is important to note that the Bitcoin protocol itself has never been successfully hacked, despite the enormous financial incentive for doing so. (However, that does mean that Bitcoin companies holding funds for third parties have not been hacked).
There are more open source project that you might realize. Some of the most commonly used open source software include WordPress, Mozilla Firefox, and OpenOffice. Other examples of open source technology include the Linux operating system and Apache web server.
Click on our infographic above for more information on Open Source technology.