Findings:

• Password Authentication Protocol
• Authentication
• User Authentication
• Message Authentication Codes
• Pluggable Authentication Module
• Java Authentication and Authorization Service
• Digest Access Authentication
• mutual authentication
• 2-factor authentication
• RSA Secret Key Challenge
• challenge
• Pepsi Challenge
• Challenge of the Future
• Real World Road Rules Challenge
• Challenge a stupid patent
• The Saltine Challenge
• 13 challenges for the 13th generation
• Nodeshell Challenge
• University Challenge
• Agnosticism is the greatest intellectual challenge
• Christian challenge
• The Cheap Beer Challenge
• Scrapheap Challenge
• Minerva challenges Arachne
• BT Global Challenge
• Front Page Challenge
• Simon Singh's Code Book Cipher Challenge Cracked
• The challenge we face
• Reading Between the Lines: Lessons from the SDMI Challenge
• 24 challenge
• Daz Doorstep Challenge
• voluntary challenges in Nethack and Slash'Em
• The Great E2 Fin de Siecle Fiction Challenge
• European Soccer Challenge
• The 2-sentence Fin de Siecle Fiction Challenge Entry
• Learning Machine Challenge
• The 1-sentence Fin de Siecle Fiction Challenge Entry
• Fiction challenge results
• Challenge of Nexar
• Triangle Challenge
• Triangle Challenge Solution
• The Long Island Challenge
• Fed Challenge
• ECCp-109 Challenge
• Challenge Coin
• Chip's Challenge
• Ferrari F355 Challenge
• American Solar Challenge
• Freedom's Challenge
• James Randi Paranormal Challenge
• Three Peaks Challenge
• BOC challenge
• Challenge for Change
• Full Metal Challenge
• Cheesily Cheerful Chart Challenge
• The Lyme Park Downhill Challenge
• Most Extreme Elimination Challenge
• E2verse Valentines Challenge (collaboration)
• challenge response
• F1 Career Challenge
• Secret Me-Meta-Node Challenge
• The 99p Challenge
• DARPA grand challenge
• Challenge everything
• E2verse previous challenge (collaboration)
• Ivan's challenge
• Three Pint Challenge
• The Mentos Challenge
• wertperch's nodeshell challenge (document)
• Puzzle Quest: Challenge of the Warlords
• The Stephen King Challenge
• Harry Potter Interactive DVD Game: Hogwarts Challenge
• Millennium Challenge 2002
• THE IRON NODER CHALLENGE
• The Notebook Challenge
• Clomid challenge
• THE IRON NODER CHALLENGE 2: ELECTRIC BOOGALOO
• The Nuzlocke challenge
• THE IRON NODER CHALLENGE 3: THIS TIME IT'S MARTENSITIC
• Secret Santa Summer Nodeshell Challenge 2011
• "So?" is a challenge
• THE IRON NODER CHALLENGE 4: FERRASSIC PARK
• The challenge of writing a meaningful free-form poem using only two letter words
• THE IRON NODER CHALLENGE 5: THE FERROUS FRONTIER
• Sahara's Math Challenge # 1
• Noah's Ark challenge
• a partner who challenges you
• THE IRON NODER CHALLENGE 6: RUST NEVER SLEEPS
• The 2013 IRON NODER CHALLENGE (document)
• THE IRON NODER CHALLENGE 7: NODE HARDER WITH A VENGEANCE
• Up for a challenge?
• THE IRON NODER CHALLENGE 8: RUST IS FOR THE WEAK
• THE IRON NODER CHALLENGE: 9 FAST 9 FERROUS
• October Skeleton Challenge
• Ice bucket challenge
• THE IRON NODER CHALLENGE XII: WE'LL RUST WHEN WE'RE DEAD
• even if you fall from an impossible challenge,
• where you see mysteries, i see challenges
• "Age by age" reading challenge
• A Challenge is Issued
• Congratulations, you are about to experience a profound challenge
• A coder stumbles upon a dormant online game where real-world prizes are won; as they play, the challenges escalate to dangerous real-life tasks
• One-for-one Challenge Quest
• firm handshake
• handshake
• Interactive Handshake Gold
• old chestnut: handshakes
• answer: handshakes
• Oklahoma handshake
• handshake number
• TCP-IP three way handshake
• secret handshake
• Winnipeg handshake
• The Neon Handshake
• We talk about the importance of a good handshake.
• Sound of a Handshake
• Protocol Droid (user)
• Protocol
• Protocols of the Elders of Zion
• Transmission Control Protocol / Internet Protocol
• Real-Time Protocol
• RFC 2324
• /etc/protocols
• tunnelling protocol
• cut and choose protocols
• RFC 821
• Quote of the Day Protocol
• do protocol
• File Transfer Protocol
• Street Performer Protocol
• Two person fair cake division protocol
• slicer fair cake division protocol
• runner's protocol
• Border Gateway Protocol
• Routing Protocols
• The Protocols of the Elders of Tralfamadore
• the Gnutella protocol
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 1
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 2
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 3
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 4
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 5
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 6
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 7
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 8
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 9
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 10
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 11
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 12
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 13
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 14
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 15
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 16
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 17
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 18
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 19
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 20
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 21
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 22
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 23
• Protocols of the Meetings of the Learned Elders of Zion: Protocol No. 24
• Protocols of the Meetings of the Learned Elders of Zion
• Kyoto protocol
• High Infection Protocol
• Jabber protocol
• FireWire protocol layers
• X.25 and AX.25 Protocols
• Protocol 7
• 101 Switching Protocols
• Coin tossing protocol
• Distance Vector Multicast Routing Protocol
• informal protocol
• Dynamic Hose Configuration Protocol
• service location protocol

If you Log in you could create a "Challenge Handshake Authentication Protocol" node. If you don't already have an account, you can register here.