Make curve and bits in LazyECPoint final.
Guard BasicKeyChain.importKey*() against accidently importing the same key twice, potentially losing a private key.
Throw when trying to set creation time of a DeterministicKey that is a leaf in the hierarchy. It would be needlessly stored, but unreadable.
Add isPubKeyOnly and isEncrypted to both ECKey.toString() and DeterministicKey.toString().