As I posted on
another thread, I have always wanted to write code to automaticlly encode and decode Lewis Carroll's Cipher.
I finally finished it and thought I would share. (I didn't check to see if it was already done, it would have burst my bubble....
)
I took the ideas/suggestions from some other threads to enable the user to change the limits (what characters are legal) and wrote 4 options in (2 with and same 2 without spaces), and while it probably isn't as secure as
this thread, it's more than good enough for my purpouses.... I also did an overkill in documenting with comments what is happening and how it works so others who are new could learn quickly and easilly what I struggled with when I first found the
"Albend translator".
Code:
;------------------------------------------------------------------------------
; Lewis Carrolls Cipher
; David Barnes 12/29/2008 14:18
;------------------------------------------------------------------------------
; Initialization
#NoEnv
#SingleInstance force
#EscapeChar ; change escape char to prevent interference in text and key...(didn't help)
Sync := 0 ; for keeping track of position in key string
OutPutText = ; obvious
Found := 0 ; toggle for last snippit
Replacement := Chr(13) . Chr(10) ; value of carrige return (CR + LF) for last snippit
; ***********************************
; **** Current Available Options ****
; ***********************************
; For letters only (no spaces) choose UpperLimit := 122 & LowerLimit := 65(26 letters *2)
; for letters only (including spaces) UpperLimit := 122 & LowerLimit := 64(26 letters * 2 + space)
; for all visible characters (incl spaces) UpperLimit := 126 & LowerLimit := 32(95 total)
; for all visible characters (no spaces) UpperLimit := 126 & LowerLimit := 33(94 total)
; For all AHK useable visible characters (excludes: parenthesis, quotes * CR) UL=126 & LL=34 (92 total)
;
; *** User Set Options: ***
Key := "Nowisthetimeforallgoodmentocometotheaidoftheircountry"
UpperLimit := 126 ; See **** Current Available Options **** above
LowerLimit := 34 ; See **** Current Available Options **** Above
; *** end user options ***
InputBox, Action,, Copy text to convert into clipboard then select E=encode or D=decode:
StringUpper, Action, Action ; converts %Action% (typed text) to uppercase
String := clipboard ; gets text to encode or decode from the clipboard
KeyLen := StrLen(Key) ; gets length of the key
Loop, Parse, String ; read the text to encode or decode one character at a time
{
Sync += 1 ; increase key counter once each loop
; (seperate from A_Index in case of a key letter outside of range)
; get numbers
KeyChar := SubStr(Key, Sync, 1) ; gets current letter of key string
KeyNum := Asc(KeyChar) ; converts it to a number (ascii value)
MsgNum := Asc(A_LoopField) ; converts message letter to number
; Convert numbers per limits
If (UpperLimit = 122 and LowerLimit = 65) ;***** letters only no spaces (52 chars) *****
{
If (MsgNum > 96 AND MsgNum < 123) ; lower case
MsgNum -= 70
Else If (MsgNum > 64 AND MsgNum < 91) ; upper case
MsgNum -= 64
Else MsgNum = 0 ; not visible character
If (KeyNum > 96 AND KeyNum < 123) ; lower case
KeyNum -= 70
Else If (KeyNum > 64 AND KeyNum < 91) ; upper case
KeyNum -= 64
Else KeyNum = 0 ; not visisble charcter
}
If (UpperLimit = 122 and LowerLimit = 64) ;***** letters & spaces only (53 chars) *****
{
If (MsgNum > 96 AND MsgNum < 123) ; lower case
MsgNum -= 69
Else If (MsgNum > 64 AND MsgNum < 91) ; upper case
MsgNum -= 63
Else If MsgNum = 32 ; a space
MsgNum = 1
Else MsgNum = 0 ; not visible character
If (KeyNum > 96 AND KeyNum < 123) ; lower case
KeyNum -= 69
Else If (KeyNum > 64 AND KeyNum < 91) ; upper case
KeyNum -= 63
Else If KeyNum = 32 ; a space
KeyNum = 1
Else KeyNum = 0 ; not visible character
}
If (UpperLimit = 126 and LowerLimit = 32) ;***** all visible + spaces (95 chars) *****
{
If (MsgNum > 126 or MsgNum < 32) ; not visible character or a space
MsgNum = 0
Else MsgNum -= 31
Loop
{
If (KeyNum > 126 or KeyNum < 32) ; if key char not visible char or space,
{ ; get & use next key char
Sync +=1 ; this is why we didn't use A_Index
If (Sync = KeyLen + 1)
Sync = 1
KeyChar := SubStr(Key, Sync, 1)
KeyNum := Asc(KeyChar)
}
Else break
If (A_Index = 999) ; just in case of an error, prevent endless loop
ExitApp
}
KeyNum -= 31
}
If (UpperLimit = 126 and LowerLimit = 33) ;***** all visible, no spaces (94 chars) *****
{
If (MsgNum > 126 or MsgNum < 33) ; not visible character or a space
MsgNum = 0
Else MsgNum -= 32
Loop
{
If (KeyNum > 126 or KeyNum < 33) ; if key char not visible char or space
{ ; get & use next key char
Sync +=1 ; this is why we didn't use A_Index
If (Sync = KeyLen + 1)
Sync = 1
KeyChar := SubStr(Key, Sync, 1)
KeyNum := Asc(KeyChar)
}
Else break
If (A_Index = 999) ; just in case of an error, prevent endless loop
ExitApp
}
KeyNum -= 32
}
If (UpperLimit = 126 and LowerLimit = 34) ;***** AHK visible + spaces (92 chars no CR) *****
{
If (MsgNum > 126 or MsgNum < 32) ; not visible character
MsgNum := -3
Else MsgNum -= 34
If (MsgNum < 8) ; eliminates ( & )
MsgNum += 2
If (MsgNum < 3) ; eliminates "
MsgNum += 1
Loop
{
If (KeyNum > 126 or KeyNum < 32 ; AHK valid visible characters
or KeyNum = 34 or KeyNum = 40 or KeyNum = 41)
{ ; get & use next key char
MsgBox, invalid key character for limits chosen
Sync +=1 ; this is why we didn't use A_Index
If (Sync = KeyLen + 1)
Sync = 1
KeyChar := SubStr(Key, Sync, 1)
KeyNum := Asc(KeyChar)
}
Else break
If (A_Index = 999) ; just in case of an error, prevent endless loop
ExitApp
}
KeyNum -= 34
If (KeyNum < 8) ; eliminates ( & )
KeyNum += 2
If (KeyNum < 3) ; eliminates "
KeyNum += 1
}
; do math (actual conversion)
If (Action = "E") ; Encoding...
NewNum := MsgNum + KeyNum - 1
Else ; Decoding...
NewNum := MsgNum - KeyNum + 1
; Convert numbers back to asci range
If (UpperLimit = 122 and LowerLimit = 65) ;***** letters only no spaces (52 chars)*****
{
If (NewNum < 0) ; get NewNum back into 0-52 range
NewNum += 53
Else If (NewNum > 52)
NewNum -= 53
If (NewNum > 26) ; putting back onto ascii range(upper case)
NewNum += 70
Else If (NewNum < 27) ; putting back onto ascii range(lower case)
NewNum += 64
}
If (UpperLimit = 122 and LowerLimit = 64) ;***** letters & spaces only(53 + errors) *****
{
If (NewNum < 0) ; get NewNum back into 0-53 range
NewNum += 54
Else If (NewNum > 53)
NewNum -= 54
If (NewNum > 27) ; putting back onto ascii range(upper case)
NewNum += 69
If (NewNum < 28) ; putting back onto ascii range(lower case)
NewNum += 63
If (NewNum = 64) ; putting back onto ascii range(space)
NewNum = 32
}
If (UpperLimit = 126 and LowerLimit = 33) ;***** all visible, no spaces (94 chars) *****
{
If (NewNum < 0) ; get NewNum back into 0-94 range
NewNum += 95
If (NewNum > 94)
NewNum -= 95
NewNum +=32 ; putting back onto ascii range
}
If (UpperLimit = 126 and LowerLimit = 32) ;***** all visible + spaces (95 chars) *****
{
If (NewNum < 0) ; get NewNum back into 0-95 range
NewNum += 96
Else If (NewNum > 95)
NewNum -= 96
NewNum +=31 ; putting back onto ascii range
}
If (UpperLimit = 126 and LowerLimit = 34) ;***** all AHK visible + spaces (92 chars) *****
{
If (NewNum < 1) ; get NewNum back into 0-92 range
NewNum += 92
Else If (NewNum > 92)
NewNum -= 92
NewNum +=34 ; putting back onto ascii range
If (NewNum < 42) ; fixing ( & )
NewNum -= 2
If (NewNum < 35) ; fixing "
NewNum -= 1
}
; convert back to characters and add to output (& reset key counter)
CurNewChar := Chr(NewNum) ; change ascii number back to a letter
OutputText .= CurNewChar ; add this letter to output
If (Sync = KeyLen) ; reset key char counter if reached end of key string
Sync = 0
}
; convert errors to carrige returns to format text for nice looks (aka, last snippit)
If (Action = "D") and (UpperLimit != 126 or LowerLimit != 34) ; only if decoding and not AHK charset
{
Loop, % StrLen(OutputText) - 1 ; loop one less because compare 2 characters @ a time
{
If (Found = 1) ; if last loop iteration found 2 consecutive errors
{
Found = 0 ; reset toggle, skip this time, & go to next char set
Continue
}
AnalyzeChar := SubStr(OutputText, A_Index, 2) ; looks at 2 characters
StringSplit, AnalyzeChar, AnalyzeChar ; splits 2 chars into AnalyzeChar1&2
ACN1 := Asc(AnalyzeChar1) ; gets ascii number of each
ACN2 := Asc(AnalyzeChar2)
If (ACN1 = LowerLimit - 1 and ACN2 = LowerLimit - 1) ; if both chars are errors(< lower range)
{
OutputText := SubStr(OutputText, 1, A_Index - 1) ; repl w/ CR value
. Replacement
. SubStr(OutputText, A_Index + 2)
Found = 1 ; flip toggle
}
}
}
Sleep, 100
clipboard =
clipboard := OutputText ; Loads output to clipboard
MsgBox, Converted text is now in the clipboard.
ExitApp
While that looks like quite a large program, I condensed it to only what is needed to do one option and this is the actual code:
Code:
Albend:
Albend =
KeyLen := StrLen(Key)
Sync := 0
Loop, Parse, Raw
{
Sync += 1
MsgNum := Asc(A_LoopField)
KeyChar := SubStr(Key, Sync, 1)
KeyNum := Asc(KeyChar)
If (MsgNum > 126 or MsgNum < 32)
MsgNum = 0
Else MsgNum -= 31
KeyNum -= 31
NewNum := MsgNum - KeyNum + 1 ; Do Math
If (NewNum < 0)
NewNum += 96
Else If (NewNum > 95)
NewNum -= 96
NewNum +=31
CurNewChar := Chr(NewNum)
Albend .= CurNewChar
If (Sync = KeyLen)
Sync = 0
}
Return
So, Thanks again HogoV!!
Edit to correct a couple errors and add AHK acceptable characters option(34-126)...
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