1 files changed, 45 insertions, 0 deletions
diff --git a/3544/CH4/EX4.4/Ex4_4.sce b/3544/CH4/EX4.4/Ex4_4.sce
new file mode 100644
index 000000000..d03258c23
--- /dev/null
+++ b/3544/CH4/EX4.4/Ex4_4.sce
@@ -0,0 +1,45 @@
+//RSA algorithm example
+
+p = 47
+q = 71
+
+n = p*q
+z = (p-1)*(q-1)
+
+e = 79                              // E<N and E & Z are coprime 
+
+i=1
+d = i
+
+//Brute-force approach to find 'd'
+while(1==1)                         
+    if modulo(i*e,z)==1 then       // (E*D)mod Z = 1
+        d=i
+        break
+    end
+    i=i+1
+end
+
+printf("%d",d)
+
+//Public key: (n,e)
+//Privae key: (n,d)
+printf("\nPublic Key: (%d,%d)\nPrivate Key: (%d,%d)\n\n",n,e,n,d)
+
+
+P = 688                         //Plaintext
+printf("Plaintext: %d\n",P)
+
+C = 1                           //Encrypted Text
+for i = 1:e
+    C = modulo(C*P,n)
+end
+
+printf("Encrypted Text: %d\n",C)
+
+P=1                             //Decrypting the encypted text 'C'
+for i = 1:d
+    P = modulo(P*C,n)
+end
+
+printf("Decrypted Text: %d\n",P)