add new repoHEADmaster

1 files changed, 97 insertions, 0 deletions

diff --git a/Master/Kryptografie/krypto1/KryptArith.java b/Master/Kryptografie/krypto1/KryptArith.java
new file mode 100644
index 0000000..d8faa16
--- /dev/null
+++ b/Master/Kryptografie/krypto1/KryptArith.java
@@ -0,0 +1,97 @@
+/**
+ * 
+ */
+
+/**
+ * @author sven
+ *
+ */
+
+import java.math.*;
+import java.util.Random;
+
+public class KryptArith {
+	char bottomChar='~';
+	char topChar='!';
+	int bottomInt=(int) bottomChar;
+	int topInt=(int) topChar;
+	
+	public BigInteger modInv(BigInteger a, BigInteger b)
+	{
+		BigInteger r1 = new BigInteger("0");
+		BigInteger r2 = new BigInteger("1");
+		BigInteger a_new = new BigInteger("0");
+		BigInteger b_new = new BigInteger("0");
+		BigInteger r1_new = BigInteger.ZERO;
+		BigInteger r2_new = BigInteger.ZERO;
+		
+		while (b.compareTo(BigInteger.ONE) != 0)
+		{
+			a_new=b;
+			try
+			{
+				b_new=a.mod(b);
+			}
+			catch (Exception e)
+			{
+				System.out.println("No Inverse "+e);
+				//System.exit(1);
+				return BigInteger.ZERO.subtract(BigInteger.ONE);
+			}
+			r1_new = r2;
+			r2_new=r1.subtract(r2.multiply(a.divide(b)));
+			a=a_new;
+			b=b_new;
+			r1=r1_new;
+			r2=r2_new;
+		}	
+		return r2;
+	}
+	public int modInv(int a, int b) throws Exception
+	{
+		int r1 = 1;
+		int r2 = 0;
+		int r1_new = 1;
+		int r2_new = 0;
+		int a_new = 0;
+		int b_new = 0;
+
+		while (b_new != 1)
+		{
+			a_new=b;
+			/*try
+			{
+				b_new=a % b;
+			}
+			catch (Exception e)
+			{
+				//System.out.println("No Inverse "+e);
+				//System.exit(1);
+				return -1;
+			}*/
+			b_new=a % b;
+			r1_new = r2;
+			r2_new = r1 - ((a / b) * r2);
+			a=a_new;
+			b=b_new;
+			r1=r1_new;
+			r2=r2_new;
+		}
+		
+		return r2;
+	}
+	public int gcd(int a, int b)
+	{
+		if (b==0) return a;
+		   return gcd(b,a%b);
+	}
+	public BigInteger gcd(BigInteger a, BigInteger b)
+	{
+		if (b.compareTo(BigInteger.ZERO) == 0) return a;
+		   return gcd(b,a.mod(b));
+	}
+	public static int gen8bitPrim() {
+		Random rnd = new Random();
+		return BigInteger.probablePrime(8, rnd).intValue();
+	}
+}