How to prove identity without revealing identity Let us say Alice publishes a book under the name of Claire. The book becomes wildly popular and now Bob comes along, claiming to be Claire, to reap all the success. How does Alice prove that she wrote the book (and Bob did not) as Claire without revealing that she is Alice? More specifically: what information can she include in her book to be able to later prove this? 

I came across "zero-knowledge proof of knowledge" which sounds relevant, but I am not familiar enough with cryptography to understand if this is what I am looking for. 

Also, can you point me to any usable implementations of such a scheme?
She can generate a key-pair and include the public key in the book. Having the private counterpart she can at any time proove that she wrote the book by signing an arbitrary statament.