Related Clues:

• Employ free codename
• It's usually associated with a password
• Don't answer the questions for first four characters in 6 down - it's an issue of security
• Release news of security issue
• Locked up by policeman, resubmit access code
• American eagle that's caught in the morning gets form of identification
• Cyber-handle
• Send message, one maybe stolen by 21
• Online handle
• Step over weapon that's required by sentry
• Log-in name
• POTUS in Twitter's @POTUS, e.g
• Security input
• Idiot returned steel key
• For one of those getting into surfing, appoint someone open to exploitation from the start