Let's have an encryption CHALLENGE!

[Agamemnus]

took some work *whew*

Code:

'WE "(Whitetiger Encryption)" decrypter:
'http://www.geocities.com/pisforpi/flyingsoft

CLS
RANDOMIZE TIMER
option1% = 1

cipherkey& = 1 + INT(RND * 1000)

IF option1% = 1 THEN
word$ = "Agamemnus >> Hello, whitetiger's smiley. How does it feel to be the smartest avatar in the world?"
word$ = word$ + "whitetiger's smiley >> Pretty good, actually. How does it feel to be talking to a smiley, Agamemnus?"
word$ = word$ + "Agamemnus >> Pretty good, actually."
word$ = word$ + "Agamemnus >> *clears voice*: 'The quick brown fox jumped over the lazy dog(s)', I think."

ELSE

'Nonsense below.

word$ = word$ + "That can I;"
word$ = word$ + "At least, the whisper goes so. Our last king,"
word$ = word$ + "Whose image even but now appear'd to us,"
word$ = word$ + "Was, as you know, by Fortinbras of Norway,"
word$ = word$ + "Thereto prick'd on by a most emulate pride,"
word$ = word$ + "Dared to the combat; in which our valiant Hamlet--"
word$ = word$ + "For so this side of our known world esteem'd him--"
word$ = word$ + "Did slay this Fortinbras; who by a seal'd compact,"
word$ = word$ + "Well ratified by law and heraldry,"
word$ = word$ + "Did forfeit, with his life, all those his lands"
word$ = word$ + "Which he stood seized of, to the conqueror:"
word$ = word$ + "Against the which, a moiety competent"
word$ = word$ + "Was gaged by our king; which had return'd"
word$ = word$ + "To the inheritance of Fortinbras,"
word$ = word$ + "Had he been vanquisher; as, by the same covenant,"
word$ = word$ + "And carriage of the article design'd,"
word$ = word$ + "His fell to Hamlet. Now, sir, young Fortinbras,"
word$ = word$ + "Of unimproved mettle hot and full,"
word$ = word$ + "Hath in the skirts of Norway here and there"
word$ = word$ + "Shark'd up a list of lawless resolutes,"
word$ = word$ + "For food and diet, to some enterprise"
word$ = word$ + "That hath a stomach in't; which is no other--"
word$ = word$ + "As it doth well appear unto our state--"
word$ = word$ + "But to recover of us, by strong hand"
word$ = word$ + "And terms compulsatory, those foresaid lands"
word$ = word$ + "So by his father lost: and this, I take it,"
word$ = word$ + "Is the main motive of our preparations,"
word$ = word$ + "The source of this our watch and the chief head"
word$ = word$ + "Of this post-haste and romage in the land."
END IF

word$ = UCASE$(word$)
FOR i% = 1 TO LEN(word$)
temp% = ASC(MID$(word$, i%, 1))
IF temp% < 65 THEN GOTO contfor1
IF temp% > 90 THEN GOTO contfor1
word.temp$ = word.temp$ + CHR$(temp%)
contfor1:
NEXT i%

word$ = word.temp$
len.ciphertext% = LEN(word$)
DIM SHARED ciphertext&(1 TO len.ciphertext%)
FOR i& = 1 TO len.ciphertext%
temp& = ASC(MID$(word$, i&, 1))
ciphertext&(i&) = cipherkey& * i& * 2& * temp&
NEXT i&

PRINT "Secret key:"; cipherkey&
cipherkey& = 0
DIM SHARED probability(1 TO 26) AS INTEGER
probability(1) = 820
probability(2) = 150
probability(3) = 280
probability(4) = 430
probability(5) = 1270
probability(6) = 220
probability(7) = 200
probability(8) = 610
probability(9) = 700
probability(10) = 20
probability(11) = 80
probability(12) = 400
probability(13) = 240
probability(14) = 680
probability(15) = 750
probability(16) = 190
probability(17) = 10
probability(18) = 600
probability(19) = 630
probability(20) = 910
probability(21) = 280
probability(22) = 100
probability(23) = 230
probability(24) = 10
probability(25) = 200
probability(26) = 10

DIM SHARED letter.num&(1 TO 26)
DIM SHARED letter.freq#(1 TO 26)
DIM SHARED letter.is&(1 TO 26)

DIM SHARED plaintext%(1 TO len.ciphertext%)
DIM SHARED plaintext.string$

'get probabilities of each number that appeared.
j% = 0
FOR i% = 1 TO len.ciphertext%
cur.num& = ciphertext&(i%) / (i% * 2)

FOR i2% = 1 TO j%
IF cur.num& = letter.num&(i2%) THEN
letter.freq#(i2%) = letter.freq#(i2%) + 1
GOTO contfor2
END IF
NEXT i2%

j% = j% + 1
letter.num&(j%) = cur.num&
letter.freq#(j%) = 1
contfor2:
NEXT i%

'scale the probabilities..
FOR i% = 1 TO j%
tot.freq% = tot.freq% + letter.freq#(i%)
NEXT i%
FOR i% = 1 TO j%
letter.freq#(i%) = 10000 * letter.freq#(i%) / tot.freq%
NEXT i%

'match up the probabilities.
FOR k% = 26 TO 1 STEP -1'26
min.least.diff% = 20000
FOR i% = 1 TO 26
least.diff% = ABS(letter.freq#(i%) - probability(k%))
IF least.diff% <= min.least.diff% THEN
min.least.diff% = least.diff%
most.likely.num& = letter.num&(i%)
END IF
NEXT i%
letter.is&(k%) = most.likely.num&
NEXT k%

'get the key!
FOR k% = 1 TO 26
FOR i% = 1 TO len.ciphertext%
IF letter.is&(k%) = ciphertext&(i%) / (i% * 2) THEN
temp# = ciphertext&(i%) / i%
temp# = temp# / k%
temp# = temp# / 26
temp# = temp# / len.ciphertext%
avg.num# = avg.num# + temp#
END IF
NEXT i%
NEXT k%

cipherkey& = avg.num#
redo1:

'match up the letters..
FOR i% = 1 TO len.ciphertext%
temp# = ciphertext&(i%) / 2
temp# = temp# / i%
temp# = temp# / cipherkey&

'without these corrections, it would be inaccurate..
IF temp# > 90 THEN cipherkey& = cipherkey& + 1: GOTO redo1
IF temp# < 65 THEN cipherkey& = cipherkey& - 1: GOTO redo1
plaintext%(i%) = temp#
NEXT i%

PRINT "Program found this key:"; cipherkey&
PRINT

'convert array to string
FOR i% = 1 TO len.ciphertext%
plaintext.string$ = plaintext.string$ + CHR$(plaintext%(i%))
NEXT i%

PRINT plaintext.string$