PolarSSL makes it easy for developers to include cryptographic and SSL/TLS capabilities in their embedded products with as little hassle as possible. It is designed to be readable, documented, tested, loosely coupled and portable.

via Light-weight, modular cryptographic and SSL/TLS library – PolarSSL.

I found the above site from this article on Slashdot.

The major change is the removal of OpenSSL as the cryptographic core of OpenVPN-NL. Instead, the Dutch government opted to include the smaller, better readable and documented open source library PolarSSL to provide the cryptographic and SSL/TLS functionality.