add new repoHEADmaster

1 files changed, 206 insertions, 0 deletions

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;
+	}
+}