Шифрование текста по ключевым числам Оформил: DeeCo Автор: http://www.swissdelphicenter.ch ```{ This two functions are used to encrypt and decrypt text. Here's how to use it: The four entries Key1, Key2, Key3 and Key4 are numbers that can range from 1 to 120. In order to decrypt a text, you must use the same numbers you used to encrypt the text. No one that doesn't know what values were used on Key1, Key2, Key3 and Key4 will be able to decrypt your text! Note that Key1*Key4 MUST be different than Key2*Key3. If any Key is zero, or Key1*Key4 is equal to Key2*Key3, the function will return ''. In Brief: Key1, Key2, Key3, Key4 : integer from range[1..120] Key1*Key4 Key2*Key3 } function Encrypt(Text : string; Key1, Key2, Key3, Key4 : Integer) : string; var BufS, Hexa, Hexa1, Hexa2 : string; BufI, BufI2, Sc, Sl, Num1, Num2, Num3, Num4, Res1, Res2, Res3, Res4 : Integer; begin Sl := Length(Text); Sc := 0; BufS := ''; if (Key1 in [1 .. 120]) and (Key2 in [1 .. 120]) and (Key3 in [1 .. 120]) and (Key4 in [1 .. 120]) then begin BufI := Key1 * Key4; BufI2 := Key3 * Key2; BufI := BufI - BufI2; if BufI = 0 then begin Result := ''; Exit; end; end else begin Result := ''; Exit; end; repeat Inc(Sc); if Sc > Sl then Num1 := 0 else Num1 := Ord(Text[Sc]); Inc(Sc); if Sc > Sl then Num2 := 0 else Num2 := Ord(Text[Sc]); Inc(Sc); if Sc > Sl then Num3 := 0 else Num3 := Ord(Text[Sc]); Inc(sc); if Sc > Sl then Num4 := 0 else Num4 := Ord(Text[Sc]); Res1 := Num1 * Key1; BufI := Num2 * Key3; Res1 := Res1 + BufI; Res2 := Num1 * Key2; BufI := Num2 * Key4; Res2 := Res2 + BufI; Res3 := Num3 * Key1; BufI := Num4 * Key3; Res3 := Res3 + BufI; Res4 := Num3 * Key2; BufI := Num4 * Key4; Res4 := Res4 + BufI; for BufI := 1 to 4 do begin case BufI of 1 : Hexa := IntToHex(Res1, 4); 2 : Hexa := IntToHex(Res2, 4); 3 : Hexa := IntToHex(Res3, 4); 4 : Hexa := IntToHex(Res4, 4); end; Hexa1 := '\$' + Hexa[1] + Hexa[2]; Hexa2 := '\$' + Hexa[3] + Hexa[4]; if (Hexa1 = '\$00') and (Hexa2 = '\$00') then begin Hexa1 := '\$FF'; Hexa2 := '\$FF'; end; if Hexa1 = '\$00' then Hexa1 := '\$FE'; if Hexa2 = '\$00' then begin Hexa2 := Hexa1; Hexa1 := '\$FD'; end; BufS := BufS + Chr(StrToInt(Hexa1)) + Chr(StrToInt(Hexa2)); end; until Sc >= Sl; Result := BufS; end; function Decrypt(Text : string; Key1, Key2, Key3, Key4 : Integer) : string; var BufS, Hexa1, Hexa2 : string; BufI, BufI2, Divzr, Sc, Sl, Num1, Num2, Num3, Num4, Res1, Res2, Res3, Res4 : Integer; begin Sl := Length(Text); Sc := 0; BufS := ''; if (Key1 in [1 .. 120]) and (Key2 in [1 .. 120]) and (Key3 in [1 .. 120]) and (Key4 in [1 .. 120]) then begin Divzr := Key1 * Key4; BufI2 := Key3 * Key2; Divzr := Divzr - BufI2; if Divzr = 0 then begin Result := ''; Exit; end; end else begin Result := ''; Exit; end; repeat for BufI := 1 to 4 do begin Inc(Sc); Hexa1 := IntToHex(Ord(Text[Sc]), 2); Inc(Sc); Hexa2 := IntToHex(Ord(Text[Sc]), 2); if Hexa1 = 'FF' then begin Hexa1 := '00'; Hexa2 := '00'; end; if Hexa1 = 'FE' then Hexa1 := '00'; if Hexa1 = 'FD' then begin Hexa1 := Hexa2; Hexa2 := '00'; end; case BufI of 1 : Res1 := StrToInt('\$' + Hexa1 + Hexa2); 2 : Res2 := StrToInt('\$' + Hexa1 + Hexa2); 3 : Res3 := StrToInt('\$' + Hexa1 + Hexa2); 4 : Res4 := StrToInt('\$' + Hexa1 + Hexa2); end; end; BufI := Res1 * Key4; BufI2 := Res2 * Key3; Num1 := BufI - BufI2; Num1 := Num1 div Divzr; BufI := Res2 * Key1; BufI2 := Res1 * Key2; Num2 := BufI - BufI2; Num2 := Num2 div Divzr; BufI := Res3 * Key4; BufI2 := Res4 * Key3; Num3 := BufI - BufI2; Num3 := Num3 div Divzr; BufI := Res4 * Key1; BufI2 := Res3 * Key2; Num4 := BufI - BufI2; Num4 := Num4 div Divzr; BufS := BufS + Chr(Num1) + Chr(Num2) + Chr(Num3) + Chr(Num4); until Sc >= Sl; Result := BufS; end;```
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