Code archives/Algorithms/Cipher
This code has been declared by its author to be Public Domain code.
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| This is a fairly simple and weak string encryption algorithm. This code handles letters and numbers only. | |||||
SuperStrict Framework brl.map Import brl.random Rem import brl.standardio Local cipher:TCipher=TCipher.Create() Local s:String="HelloHowAreYouToday" Print s s=cipher.Encrypt(s) Print s s=cipher.UnEncrypt(s) Print s EndRem Type TCipher Field map:TMap[2] Method New() map[0]=New TMap map[1]=New TMap EndMethod Method Encrypt:String(s:String) Local r:String Local n:Int For n=0 To s.length-1 r:+String(map[0].valueforkey(Chr(s[n]))) Next Return r EndMethod Method Decrypt:String(s:String) Local r:String Local n:Int For n=0 To s.length-1 r:+String(map[1].valueforkey(Chr(s[n]))) Next Return r EndMethod Function Create:TCipher(seed:Int=0) Local cipher:TCipher Local char:String[62] Local n:Int,c:String SeedRnd(seed) cipher=New TCipher char[0]="0" char[1]="1" char[2]="2" char[3]="3" char[4]="4" char[5]="5" char[6]="6" char[7]="7" char[8]="8" char[9]="9" char[10]="a" char[11]="b" char[12]="c" char[13]="d" char[14]="e" char[15]="f" char[16]="g" char[17]="h" char[18]="i" char[19]="j" char[20]="k" char[21]="l" char[22]="m" char[23]="n" char[24]="o" char[25]="p" char[26]="q" char[27]="r" char[28]="s" char[29]="t" char[30]="u" char[31]="v" char[32]="w" char[33]="x" char[34]="y" char[35]="z" char[36]="A" char[37]="B" char[38]="C" char[39]="D" char[40]="E" char[41]="F" char[42]="G" char[43]="H" char[44]="I" char[45]="J" char[46]="K" char[47]="L" char[48]="M" char[49]="N" char[50]="O" char[51]="P" char[52]="Q" char[53]="R" char[54]="S" char[55]="T" char[56]="U" char[57]="V" char[58]="W" char[59]="X" char[60]="Y" char[61]="Z" For n=0 To char.length-1 Repeat c:String=char[Rand(0,61)] If Not cipher.map[1].contains(c) cipher.map[0].insert char[n],c cipher.map[1].insert c,char[n] Exit EndIf Forever Next Return cipher EndFunction EndType |
Comments
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| Why not extend it to all of ASCII? |
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| You should do that. |
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SuperStrict Import brl.random Rem Import brl.standardio Local cipher:TCipher=TCipher.Create() Local s:String="HelloHowAreYouToday" Print s s=cipher.Encrypt(s) Print s s=cipher.Decrypt(s) Print s EndRem Function KnuthShuffle:Int[](n:Int) Local k:Int[n] Local i:Int,j:Int,b:Int For i=0 To n-1 k[i]=i Next For i=0 To n-2 j=Rand(i,n-1) b=k[i] k[i]=k[j] k[j]=b Next Return k End Function Type TCipher Field enc:Int[],dec:Int[] Method New() 'map[0]=New TMap 'map[1]=New TMap EndMethod Method Encrypt:String(s:String) Local r:String Local n:Int For n=0 To s.length-1 r:+Chr(enc[s[n]]) Next Return r EndMethod Method Decrypt:String(s:String) Local r:String Local n:Int For n=0 To s.length-1 r:+Chr(dec[s[n]]) Next Return r EndMethod Function Create:TCipher(seed:Int=0) Local cipher:TCipher Local n:Int SeedRnd(seed) cipher=New TCipher cipher.enc=knuthshuffle(256) cipher.dec=New Int[256] For n=0 To 255 cipher.dec[cipher.enc[n]]=n Next Return cipher EndFunction EndType Done. |
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| Nice. |
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