Encryption is the process of converting a normal message (plain text) into a meaningless message (Ciphertext). Whereas, Decryption is the process of converting a meaningless message (Cipher text) into its original form (Plain text). In this article, we will take forward the idea of encryption and decryption and draft a python program.
In this article, we will be given a single-line message as input it is either encoded or decoded as per requirement and the resultant message is printed as output. Here, the conversion has been done by replacing A to Z, B to Y, … Z to A. The case of the characters, numbers, spaces, and special characters present in the message is being kept unchanged.
Sample Example 1:
Encryption
Input : Hello World Output : Svool Dliow
Explanation: (Reference- conversion table)
- H is replaced with S
- e is replaced with v
- l is replaced with o
- W is replaced with D
- r is replaced with i
Decryption
Input : Svool Dliow Output : Hello World
Explanation: (Reference- conversion table)
- S is replaced with H
- v is replaced with e
- o is replaced with l
- D is replaced with W
- i is replaced with r
Sample Example 2:
Encryption
Input : GeeksForGeeks Output : TvvphUliTvvph
Explanation: (Reference- conversion table)
- G is replaced with T
- e is replaced with v
- k is replaced with p
- s is replaced with h
- F is replaced with U
- o is replaced with l
- r is replaced with i
Decryption
Input : TvvphUliTvvph Output : GeeksForGeeks
Explanation: (Reference- conversion table)
- T is replaced with G
- v is replaced with e
- p is replaced with k
- h is replaced with s
- U is replaced with F
- l is replaced with o
- i is replaced with r
Below is the implementation.
Python3
# Taking input from userdata = 'Welcome to GeeksForGeeks...'# conversion Chartconversion_code = { # Uppercase Alphabets 'A': 'Z', 'B': 'Y', 'C': 'X', 'D': 'W', 'E': 'V', 'F': 'U', 'G': 'T', 'H': 'S', 'I': 'R', 'J': 'Q', 'K': 'P', 'L': 'O', 'M': 'N', 'N': 'M', 'O': 'L', 'P': 'K', 'Q': 'J', 'R': 'I', 'S': 'H', 'T': 'G', 'U': 'F', 'V': 'E', 'W': 'D', 'X': 'C', 'Y': 'B', 'Z': 'A', # Lowercase Alphabets 'a': 'z', 'b': 'y', 'c': 'x', 'd': 'w', 'e': 'v', 'f': 'u', 'g': 't', 'h': 's', 'i': 'r', 'j': 'q', 'k': 'p', 'l': 'o', 'm': 'n', 'n': 'm', 'o': 'l', 'p': 'k', 'q': 'j', 'r': 'i', 's': 'h', 't': 'g', 'u': 'F', 'v': 'e', 'w': 'd', 'x': 'c', 'y': 'b', 'z': 'a'}# Creating converted outputconverted_data = ""for i in range(0, len(data)): if data[i] in conversion_code.keys(): converted_data += conversion_code[data[i]] else: converted_data += data[i]# Printing converted outputprint(converted_data) |
Dvoxlnv gl TvvphUliTvvph...
Approach: Using strings and index() method
Python3
# Taking input from userdata = 'Welcome to GeeksForGeeks...'# conversion Chartla="abcdefghijklmnopqrstuvwxyz"ua="ABCDEFGHIJKLMNOPQRSTUVWXYZ"lra=la[::-1]ura=ua[::-1]# Creating converted outputconverted_data = ""for i in range(0, len(data)): if data[i] in la: converted_data+=lra[la.index(data[i])] elif data[i] in ua: converted_data+=ura[ua.index(data[i])] else: converted_data+=" "# Printing converted outputprint(converted_data) |
Dvoxlnv gl TvvphUliTvvph
Method #3: Using maketrans(), translate()
Python3
# Fn to encrypt the messagedef encrypt(message): conversion_table = str.maketrans("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", "zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA") return message.translate(conversion_table) # Initializing the innputmessage = "Hello World"# Calling Functionencrypted_message = encrypt(message)# print the encrypted messagesprint(encrypted_message) |
Svool Dliow
