SecurityException: BC provider not installed

You should "register" BC in JRE. You can do it in two ways: put bcprov.jar in $JRE/lib/ext folder and add in $JRE/lib/security/java.security line

security.provider.N=org.bouncycastle.jce.provider.BouncyCastleProvider

or put bcprov.jar in classpath, don't modify java.security, but add in code somewhere

static { Security.addProvider(new BouncyCastleProvider());  }

http://www.bouncycastle.org/wiki/display/JA1/Provider+Installation