cyberprojectpresentationcaeserciphers.pptx

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1. Cyber Security Presentation by -228W1A1272,C6

2. Decrypting Caesar Cipher :

3. Decrypting Caesar Cipher: Overview A Caesar Cipher is a simple substitution cipher where each letter in the plaintext is shifted a certain number of places down or up the alphabet. Decrypting Caesar Cipher: Definition T he Caesar Cipher is a basic encryption technique that involves shifting each letter of the plaintext by a fixed number of positions down or up the alphabet to produce the ciphertext.

4. Decrypting Techniques Brute Force Attack : One of the simplest ways to decrypt a Caesar Cipher is through a brute force attack. This involves systematically trying all possible shifts until the correct plaintext is revealed. Since there are only 25 possible shifts in a Caesar Cipher (excluding the original message), this method is feasible. Frequency Analysis: : Another effective technique is frequency analysis. This method relies on the fact that certain letters appear more frequently in the English language. For instance, 'E' is the most common letter. By analyzing the frequency of letters in the ciphertext and comparing it to the frequency distribution of letters in the english language, one can deduce the most likely to shift :

5. Python code for Decrypting caesar cipher: def encrypt(plaintext,key): ciphertext=' ' for letter in plaintext: letter = letter.lower() if not letter==' ': index=letters.find(letter) if index==-1: ciphertext +=letter else: new_index =index+key if new_index>=26: new_index-=26 plaintext=' ' for letter in ciphertext: letter = letter.lower() if not letter==' ': index=letters.find(letter) if index==-1: plaintext += letter else: new_index =index - key if new_index<0: new_index += 26 plaintext +=letters[new_index] return plaintext v ciphertext +=letters[new_index] return ciphertext def decrypt(ciphertext,key): plaintext=' ' for letter in ciphertext: letter = letter.lower() if not letter==' ': index=letters.find(letter) if index==-1: plaintext += letter else:

6. if new_index<0: new_index += 26 plaintext +=letters[new_index] return plaintext print() print('CAESAR CIPHER PROGRAM') print() print('Do You Want To Encrypt Or Decrypt?') user_input =input('e/d: ').lower() print() if user_input =='d': print("DECRYPTION MODE SELECTED") print() key=int(input('enter the key (1 through 26): ')) text=input('Enter the text to decrypt: ') plaintext=decrypt(text,key) print("PLAINTEXT: ",{plaintext}) elif user_input =='e': print("ENCRYPTION MODE SELECTED") print() key=int(input('enter the key (1 through 26): ')) text=input('Enter the text to encrypt: ') ciphertext=encrypt(text,key) print('CIPHERTEXT: ',{ciphertext})

7. Port scanners are essential tools in the field of network security, allowing administrators and researchers to assess the security posture of their systems by identifying open ports and services. In this report, we delve into the concept of port scanners, their types, functionalities, applications, and their significance in maintaining robust network security. Port S canner:

8. Types: Applications : 1 . TCP Port Scanners 2 . UDP Port Scanners: 3 . SYN Scanners: 4 . Stealth Scanners: Network Discovery: Port scanners are instrumental in discovering devices and services within a network. By scanning for open ports, administrators can identify active hosts and the services they offer. Vul nerability Assessment : Port scanners assist in identifying potential vulnerabilities in networked systems. Unnecessary open ports or services running on outdated versions may pose security risks, which can be mitigated upon detection. Penetration Testing: Ethical hackers and security professionals use port scanners as part of penetration testing activities to assess the security posture of systems. By identifying open ports and services, they can simulate attacks and evaluate the effectiveness of defense mechanisms. 01 02 03 04 Intrusion Detection: Port scanning activity can also be indicative of malicious intent. Intrusion detection systems (IDS) utilize port scanners to monitor network traffic and detect suspicious behavior, such as repeated scanning of multiple ports within a short time frame.

9. fr om socket import * def conScan(tgtHost,tgtPort): try: connskt = socket(AF_INET ,SOCK_STREAM) connskt.connect((tgtHost,tgtPort)) print('[+]%d/tcp open'% tgtPort) connskt.close() except: print('[+]%d/tcp closed'% tgtPort) if _name_ =='_main_': conScan('216.58.207.238',80) python code for port scanner:

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