initial commit / add all books

11 files changed, 298 insertions, 0 deletions

diff --git a/3544/CH4/EX4.17/Ex4_17.sce b/3544/CH4/EX4.17/Ex4_17.sce
new file mode 100644
index 000000000..d11259888
--- /dev/null
+++ b/3544/CH4/EX4.17/Ex4_17.sce
@@ -0,0 +1,25 @@
+
+//Longitudinal redundancy check
+
+data = [ "11100100","11011101","00111001","00101001" ]
+disp("Original data")
+disp(data)
+data = bin2dec(data)
+
+lrc = 0.
+
+for i=1:length(data)
+    lrc = bitxor(lrc,data(i))
+end
+
+disp("LRC: ")
+
+for i=1:7
+    if lrc<(2^(8-i)) then
+        printf("0")
+    else
+        printf("%s",dec2bin(lrc))
+        break        
+    end
+end
+
diff --git a/3544/CH4/EX4.18/Ex4_18.sce b/3544/CH4/EX4.18/Ex4_18.sce
new file mode 100644
index 000000000..378f06094
--- /dev/null
+++ b/3544/CH4/EX4.18/Ex4_18.sce
@@ -0,0 +1,17 @@
+// Simple message digest

+

+n = 7391743                         //Message

+printf("Original number is %d\n",n)

+

+n_str = string(n)                   //Conversion of integer to string for easy access

+l = length(n_str)                   

+n_v = strsplit(n_str,1:l-1)         //String to vector of characters

+

+d = 1

+for i=1:l                                       

+    d = d * ( ascii(n_v(i:i)) - ascii('0'))        //

+    d = modulo(d,10)

+    i = i+1

+end

+

+printf("Message digest is %d\n",d)

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)

diff --git a/3544/CH4/EX4.5.1/Ex4_5_1.sce b/3544/CH4/EX4.5.1/Ex4_5_1.sce
new file mode 100644
index 000000000..df0f7cd5b
--- /dev/null
+++ b/3544/CH4/EX4.5.1/Ex4_5_1.sce
@@ -0,0 +1,11 @@
+

+//ElGamal Key Generation

+

+p = 11

+e1 = 2

+d = 3

+

+e2 = modulo(e1^d,p)

+

+disp("Public key:")

+printf("(%d,%d,%d)",e1,e2,p)

diff --git a/3544/CH4/EX4.5.2/Ex4_5_2.sce b/3544/CH4/EX4.5.2/Ex4_5_2.sce
new file mode 100644
index 000000000..8642b7a41
--- /dev/null
+++ b/3544/CH4/EX4.5.2/Ex4_5_2.sce
@@ -0,0 +1,13 @@
+

+//ElGamal Key Encryption

+

+r = 4 

+pt = 7

+e1 = 2

+e2 = modulo(e1^d,p)

+

+c1 = modulo(e1^r,p)

+c2 = modulo(pt*e2^r,p)

+

+disp("Cipher text")

+printf("(%d,%d)",c1,c2)

diff --git a/3544/CH4/EX4.5.3/Ex4_5_3.sce b/3544/CH4/EX4.5.3/Ex4_5_3.sce
new file mode 100644
index 000000000..35d0259ab
--- /dev/null
+++ b/3544/CH4/EX4.5.3/Ex4_5_3.sce
@@ -0,0 +1,30 @@
+

+//ElGamal Key Decryption

+

+// Move scilab to current file directory

+[u,t,n] = file()

+n = strcat(n)

+file_name = basename(n)+fileext(n)

+file_name = strcat(file_name)

+ind=strindex(n,file_name)

+path = part(n,1:ind-1)

+chdir(path)

+

+exec("Chapter_4.sci",-1)

+

+p = 11

+r = 4 

+pt = 7

+d = 3

+e1 = 2

+e2 = modulo(e1^d,p)

+

+c1 = modulo(e1^r,p)

+c2 = modulo(pt*e2^r,p)

+

+x =c1^d

+x_inv = mod_inv(x,p)

+

+pt = modulo(c2*x_inv,p)

+disp("Original plaintext")

+disp(pt)

diff --git a/3544/CH4/EX4.5/Ex4_5.sce b/3544/CH4/EX4.5/Ex4_5.sce
new file mode 100644
index 000000000..c588dc704
--- /dev/null
+++ b/3544/CH4/EX4.5/Ex4_5.sce
@@ -0,0 +1,36 @@
+// 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 = 10                            //Example plaintext

+

+printf("Plaintext: %d\n",PT)

+

+C = modulo(PT^e,n)

+printf("\nEncrypted Text Code: %d\n\n",C)

+

+PT=1

+for i = 1:d

+    PT = modulo(PT*C,n)

+end

+

+printf("Decrypted Text: %d\n",PT)       //Conversion to plain text in ASCII

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

diff --git a/3544/CH4/EX4.62/Ex4_62.sce b/3544/CH4/EX4.62/Ex4_62.sce
new file mode 100644
index 000000000..787468ced
--- /dev/null
+++ b/3544/CH4/EX4.62/Ex4_62.sce
@@ -0,0 +1,23 @@
+// Knapsack algorithm for Public Key Encryption

+

+PT = [0 1 1 0 1 1; 1 1 1 0 0 0; 0 1 0 1 1 0]

+

+disp("Plain text")

+disp(PT)

+

+K = [1 7 8 12 14 20]

+disp("Knapsack:")

+disp(K)

+

+[row,col] = size(PT)

+C = []

+for i=1:row

+    sum=0

+    for j=1:col

+        sum = sum+PT(i,j)*K(j:j)

+    end

+    C(i:i) = sum

+end

+

+disp("Cipher text:")

+disp(C)

diff --git a/3544/CH4/EX4.9.1/Ex4_9_1.sce b/3544/CH4/EX4.9.1/Ex4_9_1.sce
new file mode 100644
index 000000000..8c934755d
--- /dev/null
+++ b/3544/CH4/EX4.9.1/Ex4_9_1.sce
@@ -0,0 +1,32 @@
+

+//ElGamal Signature

+

+// Move scilab to current file directory

+[u,t,n] = file()

+n = strcat(n)

+file_name = basename(n)+fileext(n)

+file_name = strcat(file_name)

+ind=strindex(n,file_name)

+path = part(n,1:ind-1)

+chdir(path)

+

+exec("Chapter_4.sci",-1)

+

+e1 = 10

+e2 = 4

+p = 19

+m = 14      //original message

+d = 16

+r = 5       //random number selected by sender

+

+r_inv = mod_inv(r,p-1)      //inverse of r modulo (p-1)

+

+s1 = modulo(e1^r,p)

+

+temp = (m-d*s1)*r_inv

+while temp<0                    //calculate modulus (p-1) for negative values

+    temp = temp+p-1

+end

+s2 = modulo(temp,p-1)

+

+printf("The signature is: (%d,%d)",s1,s2)

diff --git a/3544/CH4/EX4.9.2/Ex4_9_2.sce b/3544/CH4/EX4.9.2/Ex4_9_2.sce
new file mode 100644
index 000000000..3f794948c
--- /dev/null
+++ b/3544/CH4/EX4.9.2/Ex4_9_2.sce
@@ -0,0 +1,21 @@
+

+//ElGamal Signature verification

+

+e1 = 10

+e2 = 4

+m = 14

+p = 19

+s1 = 3

+s2 = 4

+

+v1 = modulo(e1^m,p)

+disp("V1")

+disp(v1)

+

+v2 = modulo(e2^s1 * s1^s2,p)

+disp("V2")

+disp(v2)

+

+disp("Since V1=V2, signature is valid")

+

+