Encryption Algorithms in Python

What is Encryption?

Encryption is a process converting the data into cipher or encrypted text. In simple words, encryption is a process of encoding the data. Encryption key is required to complete the process of encryption.

What is Decryption?

Decryption is a process of converting the encrypted or cipher text into plain text. It is also called decoding of data. Decryption uses the same key which is used for encryption.

The process of encryption and decryption is called cryptography. Cryptography is a method that can make secure communication between two users in coded messages. Cryptography gives a secure and private platform for the confidential messages sent from one user to another.

Cryptography and its key terms

Cryptography is a process of hiding messages, that provides privacy and security. There are a few terminologies used in cryptography, including:

• Plain text: The plain text is the original text which can be read by the user. The plain text is used for encryption, and is converted to cipher text.
• Cipher text: Cipher text is the encrypted text provided after encryption.
• Encryption: Converting plain text to cipher text is called encryption.
• Decryption: It is a process of converting the cipher text into plain text.

The process of encryption and decryption needs a key. Two methods are used for encryption and decryption processes: Symmetric Key and Asymmetric Key.

Let's understand the process of encryption and decryption using these keys.

Symmetric Key

Symmetric Key is an encryption key which uses same key for encoding and decoding. The process of encryption mostly uses the symmetric key for encoding the plain text. This type of encryption is not a secure method for encrypting the plain text, as it uses the same key for decryption, which is used for encryption. Having the same key for decryption allows to decide the encrypted text easily, thus it is not a safe method for encryption.

Implementing Encryption with Symmetric key

Python provides a cryptography library for implementing encryption and decryption processes.

This library can be installed using the pip command in Python:

The cryptography library provides the Fernet module by which we will complete the encryption and decryption. Let's implement the encryption process using the symmetric key.

Code:

Output:

Plain Text :  Encryption and Decryption
Encrypted Text :  b'gAAAAABlL5v9jYxguZqOifo0hyW51auQbd6H68Up63s6XGt8dfwBBnTCRF-fKjrdnNArlMhdwfGRmYYIAFmi3yfwShPYc6CwwWAUSP9wPoMz4p4STkmBtYk='
Decrypted Text : Encryption and Decryption

In this, we have imported the Fernet module of the cryptography package. Then, we generated the key for encryption and decryption and converted the string into a byte string (encoded the text). We will make an instance of the Fernet class with the encryption key. Then, the string is encrypted using the Fernet instance. Then, the string can be decrypted using the same key used for encryption.

Asymmetric Key

The encryption using the asymmetric key uses two keys, public and private keys. The public key is used for the encryption. Decryption is done using the private key. Encryption with asymmetric key is more secure and safe method, as the decryption key is private and can't be accessed easily by everyone. The encryption key is public and can be accessed by anyone who wants to send the data. The connection is secure and is one-to-one encrypted.

Implementation of Encryption with Asymmetric key

Python provides the rsa library, which is used to implement encryption and decryption of text.

This library can be installed using the pip command in Python.

Code:

Output:

Plain Text :  Encryption and Decryption
Encrypted Text :  b'4\tv\x86\xa81\xeb1\x84\xbd\xae\xe8K\x84\xc0\xe8p\xdb\xe1\x92\xfcC&\x11;g\x16-\xc7\xc2I\xa0\xf9^\xbcy^\xf7\xfc\x1b\\\nZ]p\x98\xb5\xc1\xc36\xe4\xf1kM\\\xc3\xa8\xc2B\xf1F6\x10\xc2'
Decrypted Text : Encryption and Decryption

We imported the rsa library, and then, using the rsa.newkeys( ) function, we generated public and private keys. The text is encoded to a byte string and encrypted the string using the public key. Then, the private key can be used for decryption of the text to convert the decrypted text into human readable and meaningful message.

Reverse Cipher Algorithm

The process of encryption can also be done using the reverse cipher algorithm. This algorithm reverses the text and gives the cipher text in reverse order. Decoding of the text is also done using the same process by reversing the encrypted text to get the plain text which is readable by humans. The text can be easily decoded as it is just reversed, thus, this algorithm is not a secure method for encryption.

Let's implement the reverse cipher algorithm in Python:

Code:

Output:

Plain Text : Encryption and Decryption
Encrypted Text : noitpyrceD dna noitpyrcnE
Decrypted Text : Encryption and Decryption

We took plain text and then encrypted it by reversing it. The decryption of the cipher text is done by reversing the encrypted text.