130 likes | 323 Views
Data Encryption. What is Encryption?. - The translation of data into a secret code. - To read an encrypted file, you must have access to a secret key or password that enables you to decrypt it. - Unencrypted data is called plain text. - encrypted data is referred to as cipher text.
E N D
What is Encryption? - The translation of data into a secret code - To read an encrypted file, you must have access to a secret key or password that enables you to decrypt it - Unencrypted data is called plain text - encrypted data is referred to as cipher text
Plain text Cipher text Dear students, My phone no. Is 24750331 Ghdu vwxghqwv, Pb skrqh qr. Lv 57083664 Encrypt Decrypt Dear students, My phone no. Is 24750331 Plain text
Activity Encrypted text: Fgct encuu yg ctg iqkpi vq vcnm cdqwv fcvc gpetarvkqp Original text:
Common algorithms of Encryption Symmetric Encryption Asymmetric Encryption
Symmetric Encryption A type of encryption where the same key is used to encrypt and decrypt the message
Symmetric Encryption (Example) Plain text 1 0 1 1 0 1 1 0 Same Key Encrypt Key XOR 1 1 0 1 1 1 1 0 Cipher text 0 1 1 0 1 0 0 1 Key XOR 1 1 0 1 1 1 1 0 Decrypt Plain text 1 0 1 1 0 1 1 0
Asymmetric Encryption Asymmetric encryption (also called public-key encryption) involves a pair of keys - a public and a private key. The public key is published in a public directory and the corresponding private key is kept secret.
Asymmetric Encryption The sender of the data encrypts the data with the public key of the receiver The data can be decrypted only with the private key of the receiver
Asymmetric Encryption Plain Text Cipher Text Plain Text
How to use two different keys? One key is the inverse of the other: Public key = 3, Private key = 1/3 Plain text = 4 Encryption: cipher text = public key * plain text = 3 * 4 = 12 Decryption: plain text = private key * cipher text = 1/3 * 12 = 4
Discussion What are the uses of encryption?
Activity Construct a simple algorithm of encryption.