Crypto-Puzzle for LCS35 Time Capsule.
Created by Ronald L. Rivest. April 2, 1999.

Puzzle parameters (all in decimal):

n = 631446608307288889379935712613129233236329881833084137558899
    077270195712892488554730844605575320651361834662884894808866
    350036848039658817136198766052189726781016228055747539383830
    826175971321892666861177695452639157012069093997368008972127
    446466642331918780683055206795125307008202024124623398241073
    775370512734449416950118097524189066796385875485631980550727
    370990439711973361466670154390536015254337398252457931357531
    765364633198906465140213398526580034199190398219284471021246
    488745938885358207031808428902320971090703239693491996277899
    532332018406452247646396635593736700936921275809208629319872
    7008292431243681

t = 79685186856218

z = 427338526681239414707099486152541907807623930474842759553127
    699575212802021361367225451651600353733949495680760238284875
    258690199022379638588291839885522498545851997481849074579523
    880422628363751913235562086585480775061024927773968205036369
    669785002263076319003533000450157772067087172252728016627835
    400463807389033342175518988780339070669313124967596962087173
    533318107116757443584187074039849389081123568362582652760250
    029401090870231288509578454981440888629750522601069337564316
    940360631375375394366442662022050529545706707758321979377282
    989361374561414204719371297211725179287931039547753581030226
    7611143659071382

To solve the puzzle, first compute w = 2^(2^t) (mod n).
Then exclusive-or the result with z.
(Right-justify the two strings first.)

The result is the secret message (8 bits per character),
including information that will allow you to factor n.
(The extra information is a seed value b, such that 
5^b (mod 2^1024) is just below a prime factor of n.)