Related Clues:

• Make secret
• Protect, in a way
• Construct cryptograms
• Write, as a secret message
• Make cryptic
• Hide, in a way
• Put into code
• Cipher
• Create a cryptogram
• Use a key, perhaps
• Make unreadable, for security
• Convert to dots and dashes
• Make hard to figure out
• Do some espionage work
• Protect from spies, in a way