Congratulations to the following teams who have won prizes for Challenge 8A:

Peter Nugent Jayen Raghvani Heena Chotai Jiten Bhatia Aditya Pande from Preston Manor High School
Daniel Edgar, Stefan Clarke, Ashley Tudhope, Jonathan Foster from Nelson Thomlinson
clever people (ha ha) from Cox Green School
Sebastian Zimmer from Latymer Upper School
Anthony Stewart from King Edward VI School Southampton
Sophie Barnes Yuna Chang Jessica Stewart Naomi Gardom from Perse School for Girls Cambridge
Ellen Benn, Sophie Durrant, Emily Lobley from TGS
Katie Matthew from Thomas More

Can you crack the final challenge this year? It is tough! Thankfully you know something about 8A - in an uncharacteristically sloppy moment Harry gave away a lot of info about this one in his last message to Charlie. Challenge 8B is an entirely different kettle of kippers. Charlie thinks it is encrypted using the Solitaire Cipher which is a highly secure pen and paper system based on a deck of cards. In real life it was invented by the famous security expert Bruce Schneier and you can find a description of it on his website. Without clues it would withstand any attack you are likely to mount, but thankfully Charlie managed to recover some info and you will find it on the Challenge 8 page. You can try to crack this using a computer or with pen and paper, but in either case you will probably find it useful to have a deck of cards to hand so you can figure out how it works. You need a deck of 52 ordinary playing cards plus two Jokers that must be distinguishable from one another. I found it helpful to make a couple slightly larger than the cards I was using as you need to find them easily in the middle of the deck. You can download a pdf of the cards I used and shrink it to fit your cards if you like. You will find it at: Harry's Jokers. As Charlie says the full key to the cipher is not available right now and it will take us a while to try to read it. We will probably manage to read a couple of extra cards a day and plan to publish them on the Challenge page between 7.30 and 8am each day. You should have them all by Christmas Eve, so by then anyone can crack the cipher if they have the patience. Of course if you have the skill (and the will to win) you might have cracked it well before then ... Good luck, Harry

What the heck it is Christmas. Here are the names of the winning teams for Challenges 6A and 7A. Congratulations to you all. If you haven't won anything yet, there is still a chance. We have 8 more prizes for Challenge 8A, and if you are one of the 78 teams still joint first in the overall leader board then perhaps you will win the GCHQ prize, the IBM prize or the Trinity College Cambridge Prize!

We have had around 150 requests for tickets so we probably can't fulfil all your Christmas wishes, but we will try to accommodate as many of you as we can. It promises to be a great event.

And now, the final Challenge of this year's competition. Sharpen your pencils and your card playing skillsfor the final episode of "The Kho i Noor Twins".

Harry

Winners of the Challenge 6A Prizes
Acta Deos Numquam Mortalia Fallunt from Wilson's
Matthew Anketell from The Judd School
george hopkins from Cheadle High School Staffs
Theo(The man from Oman)Smith Sam (Stretch)Armstrong James (Hp boy)Hardy-Pickering Ronan (JavaWizKid)McCann-Jackson Veronique (Vedge)Wilkinson Andy (No) Ye Olivia (Marlando)Marland James (The Mauler) Moran from Range High School
Caitlin Rich, Sara Rajendran, Avantika Phaltankar, Devashree Pattni, Yee Lam and Lucy Edwards. from Manchester High School for Girls
Emma Day, Tilly Onyett, Chloe Dimmock, Kayleigh Moore, Tawney Evans, Alice Law. from Abbey College
Mathew Wragg Sean McCabe from Nelson Thomlinson
Curiouser and curiouser! from Oxford High School

Winners of the Challenge 7A Prizes
Will Neaverson Sam Udale Smith Athanasius Andriopolous George Timbrell from King Edward's School
Krishna, Helen, Ashorya from Bishopshalt School
Norman Ong from Woodhouse College
Heather Allen Holly Hunt Alina Sovetkina Maisie Nash from Guildford High School
Andrew Stoner Jack Trzcinski Peter Lennon Toni Hodder Michael Bussey Stuart Bushnell from William Farr School
David Alexander, Noah, Cawthray, Katya Chambers, Ben Davies, Alfie Digby, Johnathon Dyke, Thea Ford, Daniel Gorton, Bethany Grant, Charles Hall, Megan Hayward, Reece Hughes, Grace Jandrell, Will Jones, Tom Kershaw, Billie Lewery, Ross MacDonald, Charlie Matthews, Tom Mewett, David Mold, Dom Poli, Josh Pugh, Leo Read, Jac Roberts, Katie Simkins, Will Smith, Johnathon Vibhishanan, Grace Ward-Allen. from Lakelands School
Evie Evans from Park House School
Daniel Chatfield from Bournemouth School

Well done! The following teams have won part A prizes for Challenge 5: Winners of the Challenge 5A Prizes Patrick Andrew Will Tom Marc from Woodbridge School Lucy Redjeb Laura Freeman Julia Freeman from Cox Green Secondary School Tom Mattinson from Nelson Thomlinson School Thomas Upton Charlie Hetherington Jack McKie Josh Jones Freya Upton Mathew Spivey from Crompton House Ania, Lucy from St Joseph's RC Primary School Yumiie Nuggets i suck at maths Sil-Tsing Cotton Knee from Woodhouse College Farheen Husain Fazila Husain from Plashet school Kiran Phagoora, Harriet Smith and Chloe Fuller from Stanground College All the best, Harry