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The ISAAC cipher: Difference between revisions

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The ISAAC cipher (view source)

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But building a strong and simple ISAAC-based stream cipher - replacing the irreparably broken RC4 - is our goal here: ISAAC's intended purpose.
<br><br>
 
=={{header|BASIC}}==
==={{header|FreeBASIC}}===
{{trans|C}}
<syntaxhighlight lang="freebasic">' version 03-11-2016
' compile with: fbc -s console
 
Dim Shared As UInteger<32> randrsl(256), randcnt
Static Shared As UInteger<32> mm(256)
Static Shared As UInteger<32> aa, bb ,cc
 
Sub ISAAC()
Dim As UInteger<32> i, x, y
cc = cc + 1
bb = bb + cc
For i = 0 To 256 -1
x = mm(i)
Select Case (i Mod 4)
Case 0 : aa = aa Xor (aa Shl 13)
Case 1 : aa = aa Xor (aa Shr 6)
Case 2 : aa = aa Xor (aa Shl 2)
Case 3 : aa = aa Xor (aa Shr 16)
End Select
aa = mm((i+128) Mod 256) + aa
y = mm((x Shr 2) Mod 256) + aa + bb : mm(i) = y
bb = mm((y Shr 10) Mod 256) + x : randrsl(i) = bb
Next
randcnt = 0
End Sub
 
#Macro mix(a, b, c, d, e, f, g, h)
a Xor= b Shl 11 : d += a : b += c
b Xor= c Shr 2 : e += b : c += d
c Xor= d Shl 8 : f += c : d += e
d Xor= e Shr 16 : g += d : e += f
e Xor= f Shl 10 : h += e : f += g
f Xor= g Shr 4 : a += f : g += h
g Xor= h Shl 8 : b += g : h += a
h Xor= a Shr 9 : c += h : a += b
#EndMacro
 
Sub randinit(flag As Long)
Dim As Long i
Dim As UInteger<32> a = &H9e3779b9 '/* the golden ratio *
Dim As UInteger<32> b = &H9e3779b9
Dim As UInteger<32> c = &H9e3779b9
Dim As UInteger<32> d = &H9e3779b9
Dim As UInteger<32> e = &H9e3779b9
Dim As UInteger<32> f = &H9e3779b9
Dim As UInteger<32> g = &H9e3779b9
Dim As UInteger<32> h = &H9e3779b9
aa = 0 : bb = 0 : cc = 0
For i = 0 To 3
mix(a, b, c, d, e, f, g, h)
Next
For i = 0 To 255 Step 8
If flag = 1 Then
a += randrsl(i ) : b += randrsl(i +1)
c += randrsl(i +2) : d += randrsl(i +3)
e += randrsl(i +4) : f += randrsl(i +5)
g += randrsl(i +6) : h += randrsl(i +7)
mix(a, b, c, d, e, f, g, h)
mm(i ) = a : mm(i +1) = b : mm(i +2) = c : mm(i +3) = d
mm(i +4) = e : mm(i +5) = f : mm(i +6) = g : mm(i +7) = h
End If
Next
If flag = 1 Then
For i = 0 To 255 Step 8
a += mm(i ) : b += mm(i +1)
c += mm(i +2) : d += mm(i +3)
e += mm(i +4) : f += mm(i +5)
g += mm(i +6) : h += mm(i +7)
mix(a, b, c, d, e, f, g, h)
mm(i )= a : mm(i +1) = b : mm(i +2) = c : mm(i +3) = d
mm(i +4)= e : mm(i +5) = f : mm(i +6) = g : mm(i +7) = h
Next
End If
ISAAC()
randcnt = 0
End Sub
 
' // Get a random 32-bit value 0..MAXINT
Function iRandom() As UInteger<32>
Dim As UInteger<32> r = randrsl(randcnt)
randcnt += 1
If randcnt > 255 Then
ISAAC()
randcnt = 0
End If
Return r
End Function
 
' // Get a random character in printable ASCII range
Function iRandA() As UByte
Return iRandom() Mod 95 +32
End Function
 
' // Seed ISAAC with a string
Sub iSeed(seed As String, flag As Long)
Dim As ULong i, m = Len(seed) -1
For i = 0 To 255
mm(i) = 0
Next
For i = 0 To 255
If i > m Then
randrsl(i) = 0
Else
randrsl(i) = seed[i]
End If
Next
randinit(flag)
End Sub
 
' // maximum length of message
'#define MAXMSG 4096
#Define _MOD_ 95 ' mod is FreeBASIC keyword
#Define _START_ 32 ' start is used as variable name
 
' // cipher modes for Caesar
Enum ciphermode
mEncipher
mDecipher
mNone
End Enum
 
' // XOR cipher on random stream. Output: ASCII string
' no maximum lenght for input and output string
Function Vernam(msg As String) As String
Dim As ULong i
Dim As String v
For i = 0 To Len(msg) -1
v += Chr(iRandA() Xor msg[i])
Next
Return v
End Function
 
' // Caesar-shift a printable character
Function Ceasar(m As ciphermode, ch As UByte, shift As UByte, modulo As UByte, _
start As UByte) As UByte
' FreeBASIC Mod does not handle negative numbers correctly
' also there is litte problem with shift (declared UByte)
' the IIF() statement helps with shift
' to avoid a negative n a 8 times modulo is added
' modulo * 8 get translateted by FreeBASIC to modulo shl 3
Dim As Long n = (ch - start) + IIf(m = mDecipher, -shift, shift) + modulo * 8
n = n Mod modulo
Return start + n
End Function
 
' // Caesar-shift a string on a pseudo-random stream
Function CeasarStr(m As ciphermode, msg As String, modulo As UByte, _
start As UByte) As String
Dim As Long i
Dim As String v
For i = 0 To Len(msg) -1
v += Chr(Ceasar(m, msg[i], iRandA(), modulo, start))
Next
Return v
End Function
 
' ------=< MAIN >=------
 
Dim As Long n, l
Dim As String msg = "a Top Secret secret"
Dim As String key = "this is my secret key"
 
Dim As String vctx, vptx
Dim As String cctx, cptx
 
l = Len(msg)
' // Encrypt: Vernam XOR
iSeed(key, 1)
vctx = Vernam(msg)
' // Encrypt: Caesar
cctx = CeasarStr(mEncipher, msg, _mod_, _start_)
' // Decrypt: Vernam XOR
iSeed(key, 1)
vptx = Vernam(vctx)
' // Decrypt: Caesar
cptx = CeasarStr(mDecipher, cctx, _mod_, _start_)
Print "message: "; msg
Print " key: "; key
Print " XOR: ";
' // Output Vernam ciphertext as a string of hex digits
For n = 0 To l -1
Print Hex(vctx[n], 2);
Next
Print
' // Output Vernam decrypted plaintext
Print "XOR dcr: "; vptx
' // Caesar
Print " MOD: ";
' // Output Caesar ciphertext as a string of hex digits
For n= 0 To l -1
Print Hex(cctx[n], 2);
Next
Print
' // Output Caesar decrypted plaintext
Print "MOD dcr: " ; cptx
 
' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End</syntaxhighlight>
{{out}}
<pre>message: a Top Secret secret
key: this is my secret key
XOR: 1C0636190B1260233B35125F1E1D0E2F4C5422
XOR dcr: a Top Secret secret
MOD: 734270227D36772A783B4F2A5F206266236978
MOD dcr: a Top Secret secret</pre>
 
=={{header|C}}==
Line 1,710 ⟶ 1,922:
Caesar decoded : a Top Secret secret ok
</pre>
=={{header|FreeBASIC}}==
{{trans|C}}
<syntaxhighlight lang="freebasic">' version 03-11-2016
' compile with: fbc -s console
 
Dim Shared As UInteger<32> randrsl(256), randcnt
Static Shared As UInteger<32> mm(256)
Static Shared As UInteger<32> aa, bb ,cc
 
Sub ISAAC()
 
Dim As UInteger<32> i, x, y
 
cc = cc + 1
bb = bb + cc
 
For i = 0 To 256 -1
x = mm(i)
Select Case (i Mod 4)
Case 0 : aa = aa Xor (aa Shl 13)
Case 1 : aa = aa Xor (aa Shr 6)
Case 2 : aa = aa Xor (aa Shl 2)
Case 3 : aa = aa Xor (aa Shr 16)
End Select
aa = mm((i+128) Mod 256) + aa
y = mm((x Shr 2) Mod 256) + aa + bb : mm(i) = y
bb = mm((y Shr 10) Mod 256) + x : randrsl(i) = bb
Next
 
randcnt = 0
 
End Sub
 
 
#Macro mix(a, b, c, d, e, f, g, h)
 
a Xor= b Shl 11 : d += a : b += c
b Xor= c Shr 2 : e += b : c += d
c Xor= d Shl 8 : f += c : d += e
d Xor= e Shr 16 : g += d : e += f
e Xor= f Shl 10 : h += e : f += g
f Xor= g Shr 4 : a += f : g += h
g Xor= h Shl 8 : b += g : h += a
h Xor= a Shr 9 : c += h : a += b
 
#EndMacro
 
Sub randinit(flag As Long)
 
Dim As Long i
Dim As UInteger<32> a = &H9e3779b9 '/* the golden ratio *
Dim As UInteger<32> b = &H9e3779b9
Dim As UInteger<32> c = &H9e3779b9
Dim As UInteger<32> d = &H9e3779b9
Dim As UInteger<32> e = &H9e3779b9
Dim As UInteger<32> f = &H9e3779b9
Dim As UInteger<32> g = &H9e3779b9
Dim As UInteger<32> h = &H9e3779b9
aa = 0 : bb = 0 : cc = 0
 
For i = 0 To 3
mix(a, b, c, d, e, f, g, h)
Next
 
For i = 0 To 255 Step 8
If flag = 1 Then
a += randrsl(i ) : b += randrsl(i +1)
c += randrsl(i +2) : d += randrsl(i +3)
e += randrsl(i +4) : f += randrsl(i +5)
g += randrsl(i +6) : h += randrsl(i +7)
 
mix(a, b, c, d, e, f, g, h)
mm(i ) = a : mm(i +1) = b : mm(i +2) = c : mm(i +3) = d
mm(i +4) = e : mm(i +5) = f : mm(i +6) = g : mm(i +7) = h
End If
Next
 
If flag = 1 Then
For i = 0 To 255 Step 8
a += mm(i ) : b += mm(i +1)
c += mm(i +2) : d += mm(i +3)
e += mm(i +4) : f += mm(i +5)
g += mm(i +6) : h += mm(i +7)
 
mix(a, b, c, d, e, f, g, h)
mm(i )= a : mm(i +1) = b : mm(i +2) = c : mm(i +3) = d
mm(i +4)= e : mm(i +5) = f : mm(i +6) = g : mm(i +7) = h
Next
End If
 
ISAAC()
randcnt = 0
 
End Sub
 
' // Get a random 32-bit value 0..MAXINT
Function iRandom() As UInteger<32>
 
Dim As UInteger<32> r = randrsl(randcnt)
randcnt += 1
If randcnt > 255 Then
ISAAC()
randcnt = 0
End If
 
Return r
 
End Function
 
' // Get a random character in printable ASCII range
Function iRandA() As UByte
 
Return iRandom() Mod 95 +32
 
End Function
 
' // Seed ISAAC with a string
Sub iSeed(seed As String, flag As Long)
 
Dim As ULong i, m = Len(seed) -1
 
For i = 0 To 255
mm(i) = 0
Next
 
For i = 0 To 255
 
If i > m Then
randrsl(i) = 0
Else
randrsl(i) = seed[i]
End If
 
Next
 
randinit(flag)
 
End Sub
 
' // maximum length of message
'#define MAXMSG 4096
#Define _MOD_ 95 ' mod is FreeBASIC keyword
#Define _START_ 32 ' start is used as variable name
 
' // cipher modes for Caesar
Enum ciphermode
mEncipher
mDecipher
mNone
End Enum
 
' // XOR cipher on random stream. Output: ASCII string
' no maximum lenght for input and output string
Function Vernam(msg As String) As String
 
Dim As ULong i
Dim As String v
 
For i = 0 To Len(msg) -1
v += Chr(iRandA() Xor msg[i])
Next
 
Return v
 
End Function
 
' // Caesar-shift a printable character
Function Ceasar(m As ciphermode, ch As UByte, shift As UByte, modulo As UByte, _
start As UByte) As UByte
 
' FreeBASIC Mod does not handle negative numbers correctly
' also there is litte problem with shift (declared UByte)
' the IIF() statement helps with shift
' to avoid a negative n a 8 times modulo is added
' modulo * 8 get translateted by FreeBASIC to modulo shl 3
Dim As Long n = (ch - start) + IIf(m = mDecipher, -shift, shift) + modulo * 8
n = n Mod modulo
Return start + n
 
End Function
 
' // Caesar-shift a string on a pseudo-random stream
Function CeasarStr(m As ciphermode, msg As String, modulo As UByte, _
start As UByte) As String
 
Dim As Long i
Dim As String v
 
For i = 0 To Len(msg) -1
v += Chr(Ceasar(m, msg[i], iRandA(), modulo, start))
Next
 
Return v
 
End Function
 
' ------=< MAIN >=------
 
Dim As Long n, l
Dim As String msg = "a Top Secret secret"
Dim As String key = "this is my secret key"
 
Dim As String vctx, vptx
Dim As String cctx, cptx
 
l = Len(msg)
' // Encrypt: Vernam XOR
iSeed(key, 1)
vctx = Vernam(msg)
' // Encrypt: Caesar
cctx = CeasarStr(mEncipher, msg, _mod_, _start_)
' // Decrypt: Vernam XOR
iSeed(key, 1)
vptx = Vernam(vctx)
' // Decrypt: Caesar
cptx = CeasarStr(mDecipher, cctx, _mod_, _start_)
Print "message: "; msg
Print " key: "; key
Print " XOR: ";
' // Output Vernam ciphertext as a string of hex digits
For n = 0 To l -1
Print Hex(vctx[n], 2);
Next
Print
' // Output Vernam decrypted plaintext
Print "XOR dcr: "; vptx
' // Caesar
Print " MOD: ";
' // Output Caesar ciphertext as a string of hex digits
For n= 0 To l -1
Print Hex(cctx[n], 2);
Next
Print
' // Output Caesar decrypted plaintext
Print "MOD dcr: " ; cptx
 
' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End</syntaxhighlight>
{{out}}
<pre>message: a Top Secret secret
key: this is my secret key
XOR: 1C0636190B1260233B35125F1E1D0E2F4C5422
XOR dcr: a Top Secret secret
MOD: 734270227D36772A783B4F2A5F206266236978
MOD dcr: a Top Secret secret</pre>
 
=={{header|Go}}==
Line 3,308 ⟶ 3,272:
TMode = (iEncrypt, iDecrypt);
TString = ARRAY [0 .. MaxStrLength - 1] OF CHAR;
THexString = ARRAY [0 .. 2 * MaxStrLength - 1] OF CHAR;
TCardIndexedFrom0To7 = ARRAY [0 .. 7] OF CARDINAL;
 
Line 3,318 ⟶ 3,283:
XorPlainText: TString = '';
ModPlainText: TString = '';
HexText: THexString;
Mode: TMode = iEncrypt;
HexText: TString;
 
(* ISAAC globals *)
(* external results *)
RandRsl: ARRAY [0 .. 256255] OF CARDINAL;
RandCnt: CARDINAL;
 
(* internal state *)
MM: ARRAY [0 .. 256255] OF CARDINAL;
AA: CARDINAL = 0;
BB: CARDINAL = 0;
Line 3,414 ⟶ 3,378:
PROCEDURE SeedIsaac(Seed: ARRAY OF CHAR; Flag: BOOLEAN);
VAR
I, MSeedLength: CARDINAL;
BEGIN
FOR I := 0 TO 255 DO
MM[I] := 0;
END;
MSeedLength := Length(Seed);
FOR I := 0 TO 255 DO
(* In case seed has less than 256 elements *)
IF I > MSeedLength THEN
RandRsl[I] := 0
ELSE
Line 3,475 ⟶ 3,439:
OrdMsgI: SHORTCARD;
BEGIN
Assign(''Msg, Destination);
FOR I := 0 TO Length(Msg) - 1 DO
OrdMsgI := ORD(Msg[I]);
Append(Destination[I] := CHR(GetRandomChar() BXOR OrdMsgI), Destination);
END;
END Vernam;
Line 3,511 ⟶ 3,475:
I: CARDINAL;
BEGIN
Assign(''Msg, Destination);
FOR I := 0 TO Length(Msg) - 1 DO
Append(Destination[I] := Caesar(M, Msg[I], GetRandomChar(), 95, ' '), Destination);
END;
END Vigenere;
Line 3,521 ⟶ 3,485:
SeedIsaac(Key, TRUE);
(* (2) Encryption *)
Mode := iEncrypt;
(* (a) XOR (Vernam) *)
Vernam(Msg, XorCipherText);
(* (b) MOD (Vigenere) *)
Vigenere(Msg, ModeiEncrypt, ModCipherText);
(* (3) Decryption *)
Mode := iDecrypt;
SeedIsaac(Key, TRUE);
(* (a) XOR (Vernam) *)
Vernam(XorCipherText, XorPlainText);
(* (b) MOD (Vigenere) *)
Vigenere(ModCipherText, ModeiDecrypt, ModPlainText);
(* program output *)
WriteString('Message: '); WriteString(Msg); WriteLn;
Line 5,708 ⟶ 5,670:
{{libheader|Wren-dynamic}}
{{libheader|Wren-fmt}}
<syntaxhighlight lang="ecmascriptwren">import "./iterate" for Stepped
import "./dynamic" for Enum
import "./fmt" for Fmt
 
/* external results */
PureFox
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