expdp ... ENCRYPTION_PWD_PROMPT=Y ...
Password: <user is asked for encryption password>
In previous version encryption password was explicit passed to expdp using parameter ENCRYPTION_PASSWORD. So could be visible via ps command or in a expdp parameter script.
new parameter ENCRPTION_PWD_PROMPT as default set to N
if the parameter is set to Y then user is asked for encryption password during export
the password is not visible via commands like PS nor stored in scripts
old 11g ENCRYPTION_PASSWORD and ENCRYPTION_PWD_PROMPT=Y can’t be used in the same time and generate an error