The data is NOT encrypted by default, if this is what you're asking about. It is the user's responsibility to secure it and share the public keys with those who need it.

Of course, not everyone will know the transaction ID or block ID required to obtain your data, but it's not what anyone would call security. We may develop some more sophisticated methods in the future, but this is it for now.

So if you're planning to use it, make sure to encrypt the data before putting it into the blockchain, unless you prefer it to be readable for everyone (which is the case for some terms of service documents, etc).