A 2l layer crypto app basic algorithm

Cyber Security/stego LSB and RAS/RSA2.py

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+import random
+
+
+#Euclid's Algo for greatest common divisor
+#used to make ot faster for larger intgers
+def gcd(a,b):
+    while b!=0:
+        a,b = b,a%b
+    return a
+
+#Euclid's extended algo for multiplicative inverse
+#calcultion
+
+def m_inv(e,phi):
+    d=0
+    x1=0
+    x2=1
+    y1=1
+    temp_phi=phi
+
+    while e>0:
+        temp1=temp_phi//e
+        temp2=temp_phi - temp1*e
+        temp_phi = e
+        e= temp2
+
+        x=x2 - temp1*x1
+        y=d - temp1*y1
+
+        x2=x1
+        x1=x
+        d=y1
+        y1=y
+
+    if temp_phi == 1:
+        return d+phi
+
+
+#prime test
+def is_prime(num):
+    if num==2:
+        return True
+    if num<2 or num%2==0:
+        return False
+    for n in range(3,int(num**0.5)+2,2):
+        if num %n ==0:
+            return False
+    return True
+
+def gen_keypair(p,q):
+    if not(is_prime(p) and is_prime(q)):
+        raise ValueError('Enter both number as prime.')
+    elif p==q:
+        raise ValueError('Both prime numbers cannot be equal')
+
+    n=p*q
+    #phi is totient of num
+    phi = (p-1)*(q-1)
+    #Choose e st e and phi(n) are coprime
+    e=random.randrange(1,phi)
+    # to ensure e anf phi(n) are coprime
+    g=gcd(e,phi)
+    while g!=1:
+        e=random.randrange(1,phi)
+        g=gcd(e,phi)
+
+    #To genertae private key
+    d=m_inv(e,phi)
+
+    #public key -> (e,n)
+    #private key -> (d,n)
+    return ((e,n),(d,n))
+
+def encrypt(pk,txt):
+    #unpack key in it's component
+    key,n=pk
+    #convert each letter in plaintext to num based on
+    #characters using a^b  mod m
+    cipher = [pow(ord(char),key,n) for char in txt]
+    #cipher is array of bytes
+    return cipher
+
+
+def decrypt(pk, ciphertxt):
+    # unpack key in it's component
+    key, n = pk
+    #geenrater plaintext based on ciphertext and key
+    #using a^b mod m
+    aux=[str(pow(char,key,n)) for char in ciphertxt]
+    plain=[chr(int(char2)) for char2 in aux]
+    return ''.join(plain)
+
+if __name__=='__main__':
+    print ("--->RSA ENCRYPTION/DECRYPTION<---")
+    p=int(input("Enter prime number 1 : "))
+    q=int(input("Enter prime number 2 : "))
+    print ("Generating Public/Private keypairs...")
+    public,private=gen_keypair(p,q)
+    print ("Public key : ",public," and private key : ",private)
+    msg=input("Enter mwssage to be encrypted : ")
+    enc_msg=encrypt(private,msg)
+    print ("Encrypted message : ")
+    print (''.join(map(lambda x: str(x), enc_msg)))
+    print ("Decrypting msf with public key", public, "...")
+    print ("YOur message : ")
+    print (decrypt(public, enc_msg))
+
+

Cyber Security/stego LSB and RAS/readme.md

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+#Stegonometry 
+
+##This technique is used to hide a text or image or visusal data into an image
+##I have provided code for LSB text strgnography
+
+#Cryptography
+
+##This technique is used to change a text into a non recognizable text meassage
+##Provides a code for RAS algorithm. (It can be easily cahnged according to the OS used for easy use)
+
+#Basic Idea
+
+##we can embedd them both to make a 2-layer crypted text app

Cyber Security/stego LSB and RAS/stego_file3.py

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+#numpy is numerical python an excent way to deal with array and large amout of data
+from statistics import mode
+
+from PIL import Image
+import numpy as np
+
+#code to convert the source image into NumPy array of pixels
+#and store the size
+def encode_img(src,msg,dest):
+    img= Image.open(src, 'r')
+    width,height=img.size
+    array=np.array(list(img.getdata()))
+
+    if img.mode == 'RGB':
+        n=3
+    elif img.mode =='RGBA':
+        n=4
+    total_pix=array.size//n
+
+    #delimiter adding and then
+    #tconverting updated message to binary form and calculate
+    #required pixels
+
+    msg += "$t3g0"
+    b_msg=''.join([format(ord(i),"08b") for i in msg])
+    req_pix=len(b_msg)
+
+    #check total pixel sufficient for secret message
+    #if yes, modify pixels' lsb to bits of secret message
+    #untill complete message with delimiter got hide
+
+    if req_pix>total_pix:
+        print("Error : Need larger file size")
+    else:
+        ind=0
+        for p in range(total_pix):
+            for q in range(0,3):
+                if ind<req_pix:
+                    array[p][q] = int(bin(array[p][q]) [2:9] + b_msg[ind], 2)
+                    ind+=1
+
+    #update pixel array and usr this to create and save it in destination provided
+
+    array=array.reshape(height, width, n)
+    enc_img=Image.fromarray(array.astype('uint8'), img.mode)
+    enc_img.save(dest)
+    print("Image Encoded Successfully")
+
+
+def decode_img(src):
+    # saving pixels of source image as array
+    # figure out mode
+    # calculating total pixels
+
+    img=Image.open(src, 'r')
+    array = np.array(list(img.getdata()))
+
+    if img.mode == 'RGB':
+        n=3
+    elif img.mode == 'RGBA':
+        n=4
+    total_pix = array.size//n
+
+    #extract lsb from each pix from top-left and store in group  of 8
+    #convert these grpups into ASCII cahracters to find hidden message
+    #utill we read delimiter
+
+    hidden_bits = ""
+    for p in range (total_pix):
+        for q in range(0,3):
+            hidden_bits += (bin(array[p][q])[2:][-1])
+
+    hidden_bits = [hidden_bits[i:i+8] for i in range(0,len(hidden_bits),8)]
+    msg=""
+    for i in range(len(hidden_bits)):
+        if msg[-5:] == "$t3g0":
+            break
+        else:
+            msg += chr(int(hidden_bits[i],2))
+
+    #check if delimiter found. If not -> no hidden message
+    if "$t3g0" in msg:
+        print("Hidden Message: ",msg[:-5])
+    else:
+        print("No Hidden Message Found")
+
+
+def stego():
+    print("---> Welcome to stego <---")
+    print("1: Encode")
+    print("2: Decode")
+
+    func=input()
+
+    if func=='1':
+        print("Enter Source Image Path")
+        src =input()
+        print("Enter Message to Hide")
+        msg=input()
+        print("Enter Destination Image Path")
+        dest=input()
+        print("Encoding...")
+        encode_img(src,msg,dest)
+
+    elif func=='2':
+        print("Enter Source Image Path")
+        src = input()
+        print("Decoding..")
+        decode_img(src)
+    else:
+        print("Error : Invalid Option Chosen")
+
+stego()
+
+

stego LSB and RAS/RSA2.py

@@ -0,0 +1,108 @@
+import random
+
+
+#Euclid's Algo for greatest common divisor
+#used to make ot faster for larger intgers
+def gcd(a,b):
+    while b!=0:
+        a,b = b,a%b
+    return a
+
+#Euclid's extended algo for multiplicative inverse
+#calcultion
+
+def m_inv(e,phi):
+    d=0
+    x1=0
+    x2=1
+    y1=1
+    temp_phi=phi
+
+    while e>0:
+        temp1=temp_phi//e
+        temp2=temp_phi - temp1*e
+        temp_phi = e
+        e= temp2
+
+        x=x2 - temp1*x1
+        y=d - temp1*y1
+
+        x2=x1
+        x1=x
+        d=y1
+        y1=y
+
+    if temp_phi == 1:
+        return d+phi
+
+
+#prime test
+def is_prime(num):
+    if num==2:
+        return True
+    if num<2 or num%2==0:
+        return False
+    for n in range(3,int(num**0.5)+2,2):
+        if num %n ==0:
+            return False
+    return True
+
+def gen_keypair(p,q):
+    if not(is_prime(p) and is_prime(q)):
+        raise ValueError('Enter both number as prime.')
+    elif p==q:
+        raise ValueError('Both prime numbers cannot be equal')
+
+    n=p*q
+    #phi is totient of num
+    phi = (p-1)*(q-1)
+    #Choose e st e and phi(n) are coprime
+    e=random.randrange(1,phi)
+    # to ensure e anf phi(n) are coprime
+    g=gcd(e,phi)
+    while g!=1:
+        e=random.randrange(1,phi)
+        g=gcd(e,phi)
+
+    #To genertae private key
+    d=m_inv(e,phi)
+
+    #public key -> (e,n)
+    #private key -> (d,n)
+    return ((e,n),(d,n))
+
+def encrypt(pk,txt):
+    #unpack key in it's component
+    key,n=pk
+    #convert each letter in plaintext to num based on
+    #characters using a^b  mod m
+    cipher = [pow(ord(char),key,n) for char in txt]
+    #cipher is array of bytes
+    return cipher
+
+
+def decrypt(pk, ciphertxt):
+    # unpack key in it's component
+    key, n = pk
+    #geenrater plaintext based on ciphertext and key
+    #using a^b mod m
+    aux=[str(pow(char,key,n)) for char in ciphertxt]
+    plain=[chr(int(char2)) for char2 in aux]
+    return ''.join(plain)
+
+if __name__=='__main__':
+    print ("--->RSA ENCRYPTION/DECRYPTION<---")
+    p=int(input("Enter prime number 1 : "))
+    q=int(input("Enter prime number 2 : "))
+    print ("Generating Public/Private keypairs...")
+    public,private=gen_keypair(p,q)
+    print ("Public key : ",public," and private key : ",private)
+    msg=input("Enter mwssage to be encrypted : ")
+    enc_msg=encrypt(private,msg)
+    print ("Encrypted message : ")
+    print (''.join(map(lambda x: str(x), enc_msg)))
+    print ("Decrypting msf with public key", public, "...")
+    print ("YOur message : ")
+    print (decrypt(public, enc_msg))
+
+