Since JDK 1.4 (I think), Sun JCE requires providers to be signed with a
private key that belongs to a certificate issued by Sun. When you add
another provider to the security manager Sun JCE and the provider
authenticate each other that way.

The disadvantage of Cryptix is, that it is not signed with an
appropriate certificate from Sun. That way, it only works outside the
sandbox, i.e. as an application without the java.lang.Security
instantiated.

Alternatives:
- use another provider, such as BouncyCastle or SunRsaSign, with proper
certificates issued by Sun
- use a clean-room implementation of the JCE, like the one from
BouncyCastle, that does not check signatures on JCE providers.
- keep outside the sandbox. Does not work for applets.

Regards
JK.