Encryption

Encryption

CompSci

Encryption

• A method of securing data for storage or transmission that scrambles it and makes it meaningless.

  
  

• Encryption is the process of converting readable data (plaintext) into an unreadable form (ciphertext) to prevent unauthorized access.

Why data need to be encrypted?

Encryption is used to protect sensitive data (e.g. passwords, credit card numbers) from hackers or interception during transmission.

Vocabulary

• Plain text is the data before encryption takes place.

• Encryption key is a type of algorithm that is used to encrypt data.

• Cipher text is scrambled data and meaningless data.

Multiple Choice

Scrambled data and meaningless data.

• Cipher text

• Encryption key

• Plain text

Open Ended

The data before encryption takes place is the meaning of?

Open Ended

What is the meaning of encryption key?

Symmetric Encryption

Symmetric encryption is the method that is uses the same key to encrypt and decrypt the data.

Simple Analogy:

• Whatsapp - sending & receiving message

• Padlock - every people need to have ONE key to open and close.

Symmetric encryption is:

Symmetric

• ​Plain text is encrypted into cipher text using an encryption key.

• The cipher text and the encryption key are sent separately to the receiving device.

• The same key is then used to decrypt the cipher text back into its plain text from

​The process for symmetric encryption is:

Asymmetric Encryption

Asymmetric encryption uses two keys: a public key and a private key.







Simple Analogy:

• HTTPS - Website use Public key to encrypting our password and Private key to decrypting our password.

• Mailbox - All people can send/drop a mail to us, but only us can open it.

Asymmetric encryption is:

Asymmetric Encryption

(a) Public key – a key that is shared openly and used to encrypt data.
(b) Private key – a secret key kept by the owner and used to decrypt data.

Public & private key

Asymmetric

• ​Plain text is encrypted into cipher text using a public key. This is also a type of encryption algorithm.

• The cipher text is transmitted to the receiving device.

• The cipher text cannot be decrypted using the public key, it is decrypted using a private key.

​The process for asymmetric encryption is:

Open Ended

Which type of encryption that is use same key to encrypt and decrypt data?

Multiple Choice

What type of encryption is this?

• Symmetric

• Asymmetric

​Thank you...