This is a PHP interface to NaCl, not Google's NativeClient.
NaCl is a new easy-to-use high-speed software library for network communication, encryption, decryption, signatures, etc. NaCl's goal is to provide all of the core operations needed to build higher-level cryptographic tools.
Install
$ git clone git://github.com/Gasol/pecl-nacl
$ cd pecl-nacl
$ phpize
$ ./configure --with-nacl
$ make install
Configuration
Add nacl extension into your php.ini
extension=nacl.so
Homebrew
$ brew install nacl
$ cd /usr/ports/security/nacl
$ make install clean
$ wget http://hyperelliptic.org/nacl/nacl-20110221.tar.bz2
$ tar jxvf nacl-20110221.tar.bz2
$ cd nacl-20110221
$ rm -rf crypto_onetimeauth/poly1305/amd64
$ sed -i -e "s/$/ -fPIC/" ${WRKSRC}/okcompilers/c
$ ./do
Support Debian (wheezy) and Ubuntu 12.04