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 +++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 Master/Kryptografie/p2/GalController.java

(limited to 'Master/Kryptografie/p2/GalController.java')

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);
+	}
+}
-- 
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