Merge pull request #136 from PGautam27/master

RSA Encryption algo

scripts/RSA_algo_EtoE_Encryption/README.md

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+# RSA ENCRYPTION ALGO IMPLEMENTATION IN PYTHON
+
+- I've imported the rsa package.
+- It generates the public and private key. 
+- It then stores the keys in keys/privkey.pem and keys/publickey.pem.
+- The keys are then loaded to the program as publickey and privatekey. 
+- The inputed text or message is encrypted with the public key.
+- Which then is put in the variable ciphertext. 
+- The private key is used to decrypt the message. 
+- Here we also verify the signature of the message and the keys, whether they are signified or not.
+
+![cipher](https://user-images.githubusercontent.com/92343715/193993832-88f54d89-a54a-4c5e-979d-0c6e9f09960d.png)

scripts/RSA_algo_EtoE_Encryption/keys/privkey.pem

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+

scripts/RSA_algo_EtoE_Encryption/keys/pubkey.pem

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+

scripts/RSA_algo_EtoE_Encryption/main.py

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+import rsa
+
+##this function generates the keys
+def generate_keys():
+    (pubKey, privKey) = rsa.newkeys(1024)
+    with open('keys/pubkey.pem', 'wb') as f:
+        f.write(pubKey.save_pkcs1('PEM'))
+
+    with open('keys/privkey.pem', 'wb') as f:
+        f.write(privKey.save_pkcs1('PEM'))
+
+##Loads the keys from the .pem files to pubkey and privkey variables
+def load_keys():
+    with open('keys/pubkey.pem', 'rb') as f:
+        pubKey = rsa.PublicKey.load_pkcs1(f.read())
+
+    with open('keys/privkey.pem', 'rb') as f:
+        privKey = rsa.PrivateKey.load_pkcs1(f.read())
+
+    return pubKey, privKey
+
+##encrypts the messages using the public key
+def encrypt(msg, key):
+    return rsa.encrypt(msg.encode('ascii'), key)
+
+##decrypts the encrypted message or ciphertext using the privatekey
+def decrypt(ciphertext, key):
+    try:
+        return rsa.decrypt(ciphertext, key).decode('ascii')
+    except:
+        return False
+
+##the sha is generated for the message and key
+def sign_sha1(msg, key):
+    return rsa.sign(msg.encode('ascii'), key, 'SHA-1')
+
+##this function verifies the sha
+def verify_sha1(msg, signature, key):
+    try:
+        return rsa.verify(msg.encode('ascii'), signature, key) == 'SHA-1'
+    except:
+        return False
+
+##generates keys
+generate_keys()
+
+##loads keys
+pubKey, privKey = load_keys()
+
+##Takes in the message and encrypts it
+message = input('Enter a message:')
+ciphertext = encrypt(message, pubKey)
+
+signature = sign_sha1(message, privKey)
+
+##It then decrypts the message.
+plaintext = decrypt(ciphertext, privKey)
+
+##the sgnature of the message is displayed
+print(f'Signature: {signature}')
+##the cipher of the message is displayed
+print(f'Cipher text: {ciphertext}')
+
+##the decrypted message is displayed
+if plaintext:
+    print(f'Plain text: {plaintext}')
+else:
+    print('Could not decrypt the message.')
+
+if verify_sha1(plaintext, signature, pubKey):
+    print('great the signature is verified')
+else:
+    print('Could not verify the message signature.')