Using a pseudonym, which is a fictitious name or alias.  Pronounced "soo-
don-a-miss."  For example, cryptocurrency transactions are pseudonymous because the aliases are the sender and recipient's public keys, not their names.  However, if someone is able to match a public key to a person's name, then all the transactions ever made by that person are visible.  Contrast with anonymous, which means nameless.  See 
Bitcoin address, 
crypto glossary and 
public key cryptography.