I have already posted my comment in other places, and I'll copy them here as people may be interested:
Looking at the CryptoHeaven source code (downloadable at the CH web site ) I can confirm that all of the messages and files stored on the server are in an encrypted form. Too bad the server code is not available, but noone wants to work for free so I can understand that...
Basically the administrators of the system have no way of knowing what is being stored on the servers because all root keys in the encryption chains end up on customer's PCs (always encrypted) or stored encrypted with customer's own passphrases which never leave their computers, nor are stored anywhere. As far as I can tell, this is a major difference between CryptoHeaven and most other online storage providers which only make the connectivity SSL secure, but not the data residing on the servers to which sys admins have access to.
The system looks to be one of a few which really delivers the level of security it claims leaving little unsaid. Although it seems possible to privately implement additional algorithms like ECC and use it to communicate with your buddies (because the code is freely available), the copyright forbids it, and there are good reasons for that too. What I would like to see is integration with PGP so that we can start sending and receiving secure mail with an already established PGP user base.
I have read somewhere that symmetric key length and hash length used are not equivalent in their cryptographic strength. This claim is irrelevant as the hash seems to be used "for display purpose only" and not in the security protocols. I have yet to see a non-encrypted hash of anything on the system, so this looks good too.
Interesting is that they cannot reset your password in case you loose it. My explanation for this is because your private key (if stored on the server) is encrypted with the hash of your password, so you must have your original password to be able to decrypt your private key. If they were to reset it, your private key would have to be re-crypted with the hash of your new password, but to do that you still need the old password to decrypt it in the first place. Cleaver.
Passwords are often the weakest links in security and to rectify that, YOU CAN STORE YOUR PRIVATE KEY LOCALLY (always encrypted). This is something that is not possible with systems like Hushmail and many others.
Perhaps ability to sign other's keys and revoke signatures would create additional web of trust, but, oh well, you can't have everything.
The functionality is great; someone wrote they are putting 'all the eggs in one basket', however it may be an attempt to do just that, there is still long way to go. Never less, it is a very usable and user-friendly product which is much more than just online storage!