From 33613a85afc4b1481367fbe92a17ee59c240250b Mon Sep 17 00:00:00 2001
From: Sven Eisenhauer <sven@sven-eisenhauer.net>
Date: Fri, 10 Nov 2023 15:11:48 +0100
Subject: add new repo

---
 Master/Kryptografie/p2/GalController.java |  76 +++++++++++
 Master/Kryptografie/p2/GalNumber.java     | 206 ++++++++++++++++++++++++++++++
 Master/Kryptografie/p2/GalTest.java       |  71 ++++++++++
 3 files changed, 353 insertions(+)
 create mode 100644 Master/Kryptografie/p2/GalController.java
 create mode 100644 Master/Kryptografie/p2/GalNumber.java
 create mode 100644 Master/Kryptografie/p2/GalTest.java

(limited to 'Master/Kryptografie/p2')

diff --git a/Master/Kryptografie/p2/GalController.java b/Master/Kryptografie/p2/GalController.java
new file mode 100644
index 0000000..00a34f2
--- /dev/null
+++ b/Master/Kryptografie/p2/GalController.java
@@ -0,0 +1,76 @@
+package krypto;
+
+public class GalController {
+	
+	int key_s = 7;
+	int key_t = 3; 
+	
+	private char encryptChar(char klar)
+	{		
+		GalNumber gn_geheim = new GalNumber();
+		GalNumber gn_klar = new GalNumber((int)klar);
+		GalNumber gn_key_s = new GalNumber(key_s);
+		GalNumber gn_key_t = new GalNumber(key_t);
+		GalNumber rijndael_mod = new GalNumber(GalNumber.RIJN_MOD);
+		
+		gn_geheim = gn_klar.add(gn_key_s).mult(gn_key_t.mod(rijndael_mod));
+		
+		System.out.println("Klar: "+gn_klar.toHex()+" Geheim: "+gn_geheim.toHex());
+				
+		return gn_geheim.toChar();
+	}
+	
+	private char decryptChar(char geheim)
+	{		
+		GalNumber gn_geheim = new GalNumber();
+		GalNumber gn_klar = new GalNumber();
+		GalNumber gn_key_s = new GalNumber(key_s);
+		GalNumber gn_key_t = new GalNumber(key_t);
+		GalNumber rijndael_mod = new GalNumber(GalNumber.RIJN_MOD);
+		
+		gn_geheim.setVal((int) geheim);
+				
+		gn_klar = gn_geheim.mult(gn_key_t.inv()).sub(gn_key_s.mod(rijndael_mod));
+		
+		System.out.println("Geheim char: "+geheim+" int "+(int)geheim+" GN Geheim: "+gn_geheim.toHex()+" Klar: "+gn_klar.toHex());
+		
+		return gn_klar.toChar();
+	}
+	
+	public String encrypt(String klarText)
+	{
+		char [] chars = new char[klarText.length()];
+		for (int i=0;i<klarText.length();i++)
+		{
+			chars[i] = encryptChar(klarText.charAt(i));
+		}
+		String geheimText=new String(chars);
+		return geheimText;
+	}
+	
+	public String decrypt(String geheimText)
+	{
+		char [] chars = new char[geheimText.length()];
+		for (int i=0;i<geheimText.length();i++)
+		{
+			//System.out.println("cipher "+i+": "+geheimText.charAt(i)+" int: "+(int) geheimText.charAt(i));
+			chars[i] = decryptChar(geheimText.charAt(i));
+		}
+		String klarText=new String(chars);
+		return klarText;
+	}
+	
+	public void setKeyS(int s)
+	{
+		key_s = s;
+	}
+	public void setKeyT(int t)
+	{
+		key_t = t;
+	}
+	public void setKeyST(int s, int t)
+	{
+		setKeyS(s);
+		setKeyT(t);
+	}
+}
diff --git a/Master/Kryptografie/p2/GalNumber.java b/Master/Kryptografie/p2/GalNumber.java
new file mode 100644
index 0000000..b598330
--- /dev/null
+++ b/Master/Kryptografie/p2/GalNumber.java
@@ -0,0 +1,206 @@
+package krypto;
+
+public class GalNumber {
+	
+	public static int RIJN_MOD = 0x11B;
+	public static int BITWIDTH = 8;
+	public static int BITMASK = 0xff;
+	public static int DIV_POS = 0;
+	public static int MOD_POS = 1;
+	private static int[] BIT_LUT = { 	
+		0x1, 0x2, 0x4, 0x8, 
+		0x10, 0x20, 0x40, 0x80,
+        0x100, 0x200, 0x400, 0x800, 
+        0x1000, 0x2000, 0x4000, 0x8000 
+    };
+	
+	private int value;
+	
+	
+	public GalNumber() {
+		this.value = 0;
+	}
+	
+	public GalNumber (int in) {
+		value = in & BITMASK;
+	}
+	
+	public GalNumber (GalNumber in) {
+		value = in.value;
+	}
+	
+	public GalNumber div(GalNumber rightOp) {
+		int[] result = new int[2];
+		result=this.reduce(rightOp);
+		return new GalNumber(result[DIV_POS]);
+	}
+	
+	private int unstrippedMult(GalNumber rightOp) {
+        int result = 0x0;
+        int bitmask=0x0;
+        int ro=rightOp.toInt();
+        int lo=this.value;
+        int temp=0x0;
+        int actBit;
+        
+        for (int i=0;i<16;i++)
+        {
+        	bitmask=(0x1 << i);
+        	actBit=ro&bitmask;
+        	if (actBit != 0) {
+        		temp=lo << i;
+        		result ^= temp;
+        	}
+        }
+        
+		return result;
+	}
+	
+	public GalNumber mult(GalNumber rightOp) {
+		int [] divmod = new int[2];
+		GalNumber gn_tmp = new GalNumber();
+		int tmp = this.unstrippedMult(rightOp);
+		gn_tmp.setVal(tmp);
+		divmod = gn_tmp.reduce(RIJN_MOD);
+		return new GalNumber(divmod[MOD_POS]);
+	}
+	
+	public GalNumber mod(GalNumber rightOp) {
+		int[] result = new int[2];
+		result=this.reduce(rightOp);
+		return new GalNumber(result[MOD_POS]);
+	}
+	
+	public GalNumber euklid(int modul, GalNumber toInvert) throws Exception {
+		
+		GalNumber a= new GalNumber(modul);
+		GalNumber b=new GalNumber(toInvert);
+		GalNumber r1=new GalNumber(0);
+		GalNumber r2=new GalNumber(1);
+		
+		GalNumber a_new=new GalNumber(0);
+		GalNumber b_new=new GalNumber(0);
+		GalNumber r1_new=new GalNumber(0);
+		GalNumber r2_new=new GalNumber(0);
+		
+		//while (b.toInt() != 1) {
+		while (b.toInt() > 1) {
+			/*if (b.toInt() == 0)
+			{
+				throw new Exception("b became ZERO"); 
+			}*/
+			a_new = b;
+			b_new= a.mod(b);
+			r1_new=r2;
+			r2_new=r1.add( ( a.div(b) ).mult(r2) );
+			
+			a=a_new;
+			b=b_new;
+			r1=r1_new;
+			r2=r2_new;
+		}
+		
+		return r2;
+	}
+	public GalNumber inv() {
+		GalNumber result = new GalNumber();
+		try {
+			result = euklid(RIJN_MOD, this);
+			
+		}
+		catch (Exception e) {
+			//System.out.println(e.getMessage());
+			result.setVal(0);
+		}
+		return result;
+	}
+	public GalNumber add(GalNumber rightOp) {
+		int sum=0;
+		sum=this.value ^ rightOp.toInt();
+		return new GalNumber(sum);
+	}
+	
+	private int[] reduce(GalNumber rightOp) {
+		return reduce(rightOp.toInt() );
+	}
+	private int[] reduce(int rightOp) {
+		
+		int [] divmod = new int[2];
+		divmod[DIV_POS]=0;
+		divmod[MOD_POS]=this.toInt();
+		int shift = 0;
+		int rightOpMSB=0;
+		int leftOpMSB=0;
+
+        // Search MSB in right Operand
+        for (int i = BIT_LUT.length - 1; i >= 0; i--)
+        {
+            if ((rightOp & BIT_LUT[i]) != 0)
+            {
+            	rightOpMSB = i;
+                break;
+            }
+        }
+        if (this.toInt() == 0) {
+        	divmod[DIV_POS]=0;
+        	divmod[MOD_POS]=0;
+            return divmod;
+        }
+        if (rightOp == 0){
+        	divmod[DIV_POS]=0;
+        	divmod[MOD_POS]=this.toInt();
+            return divmod;
+        }
+        do {
+            // Search MSB in left Operand
+            for (int i = BIT_LUT.length - 1; i >= 0; i--)
+            {
+                if ((divmod[MOD_POS] & BIT_LUT[i]) != 0)
+                {
+                	leftOpMSB = i;
+                    break;
+                }
+            }
+            if (leftOpMSB >= rightOpMSB)
+            {
+                // Align the ro to the MSB of the lp and add this
+                shift = leftOpMSB - rightOpMSB;
+
+                // Save result vor integral div
+                divmod[DIV_POS] = divmod[DIV_POS] ^ (0x1 << shift);
+
+                // Next polynom for division
+                divmod[MOD_POS] = divmod[MOD_POS] ^ (rightOp << shift);
+
+                if (divmod[MOD_POS] == 0)
+                    return divmod;
+            }   
+        	
+        } while (leftOpMSB>=rightOpMSB);
+		return divmod;
+	}
+	
+	public GalNumber sub(GalNumber rightOp) {
+		return new GalNumber(this.add(rightOp));
+	}
+	
+	public int toInt() {
+		return this.value;
+	}
+	
+	public String toHex() {
+		return "'"+Integer.toHexString(this.toInt()).toUpperCase()+"'";
+	}
+	
+	public String toString() {
+		return Integer.toString(this.value);
+	}
+	
+	public char toChar() {
+		return (char) this.toInt();
+	}
+	
+	public void setVal(int a) {
+		value=a;
+	}
+}
diff --git a/Master/Kryptografie/p2/GalTest.java b/Master/Kryptografie/p2/GalTest.java
new file mode 100644
index 0000000..88cb3f6
--- /dev/null
+++ b/Master/Kryptografie/p2/GalTest.java
@@ -0,0 +1,71 @@
+package krypto;
+import java.util.Random;
+
+public class GalTest {
+	private int testSize;
+	private long startTime;
+	private long finishTime;
+	
+	private GalNumber[] galNumbers;
+	
+	public GalTest() {
+		this.setTestSize(1000);
+		this.init();
+	}
+		
+	public GalTest(int testSize) {
+		this.setTestSize(testSize);
+		this.init();
+	}
+	
+	public void init() {
+		galNumbers = new GalNumber[testSize];
+		Random rnd = new Random();
+		if (galNumbers != null) {
+			for (int i=0;i<galNumbers.length;i++) {
+				galNumbers[i]= new GalNumber(rnd.nextInt());
+			}
+		}
+	}
+	
+	public void doInvTest() {
+		if (galNumbers != null) {
+			this.setStartTime(System.currentTimeMillis());
+			for (int i=0;i<galNumbers.length;i++) {
+				//System.out.println(galNumbers[i].inv());
+				galNumbers[i].inv();
+				if ( (i % (galNumbers.length/10)) == 0) {
+					System.out.println("Inverse von "+galNumbers[i].toHex()+" ist "+galNumbers[i].inv());
+				}
+			}
+			this.setFinishTime(System.currentTimeMillis());
+		}
+		System.out.println("Test took "+(finishTime-startTime)+" milliseconds");
+	}
+	
+	public void setTestSize(int i) {
+		this.testSize = i;
+	}
+	
+	public int getTestSize() {
+		return testSize;
+	}
+
+	public long getStartTime() {
+		return startTime;
+	}
+
+	public void setStartTime(long startTime) {
+		this.startTime = startTime;
+	}
+
+	public long getFinishTime() {
+		return finishTime;
+	}
+
+	public void setFinishTime(long finishTime) {
+		this.finishTime = finishTime;
+	}
+	
+	
+}
-- 
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