From 7f60ea012dd2524dae921a2a35adbf7ef21f2bb6 Mon Sep 17 00:00:00 2001
From: prashantsinalkar
Date: Tue, 10 Oct 2017 12:27:19 +0530
Subject: initial commit / add all books

---
 3544/CH4/EX4.6/Ex4_6.sce | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 3544/CH4/EX4.6/Ex4_6.sce

(limited to '3544/CH4/EX4.6')

diff --git a/3544/CH4/EX4.6/Ex4_6.sce b/3544/CH4/EX4.6/Ex4_6.sce
new file mode 100644
index 000000000..632ad2b7f
--- /dev/null
+++ b/3544/CH4/EX4.6/Ex4_6.sce
@@ -0,0 +1,45 @@
+// RSA Encryption scheme
+
+p = 7                      //Large prime numbers
+q = 17                     //Small values taken here for convenience of calculation
+                           //and explanation
+
+n = p*q
+z = (p-1)*(q-1)
+
+e = 5                              // e<n and e & z are coprime 
+
+i=1
+d = i                       
+while(1==1)                        //Calcualtion of 'd' from e and z
+    if modulo(i*e,z)==1 then       // (e*d)mod z = 1
+        d=i
+        break
+    end
+    i=i+1
+end
+
+printf("\nPublic Key: (%d,%d)\nPrivate Key: (%d,%d)\n\n",n,e,n,d)
+
+PT = 'F'                            //Example plaintext in ASCII
+P = ascii(PT)-ascii('A')+1          //Conversion of ASCII to integer code 
+                                    //(A=1,B=2,C=3, ... )
+printf("Plaintext: %s\n",PT)
+printf("Plain text Integer code: %d\n\n\",P)
+
+C = 1
+for i = 1:e
+    C = modulo(C*P,n)
+end
+
+C = modulo(C,n)
+printf("Encrypted Text Code: %d\n\n",C)
+
+P=1
+for i = 1:d
+    P = modulo(P*C,n)
+end
+
+PT = ascii(ascii('A')+P-1)
+printf("Decrypted Text Code: %d\n",P)   //Decryoted code
+printf("Decrypted Text: %s\n",PT)       //Conversion to plain text in ASCII
-- 
cgit