Encryption (A2.4 Network security)

Encryption

Converting readable data (plaintext) into unreadable ciphertext to prevent unauthorized access

• Only those with the correct decryption key can decrypt (convert back to plaintext)

I. Types of cryptography

types fo cryptography/encryption

Symmetric cryptography

1 shared secret key for both encryption and decryption

• Usually used for local sharing of data

Advantages (symmetric cryptography)

Fast and efficient, so good for the transmission of bulk data

Disadvantages (symmetric cryptography)

If this key is stole, the attacker can read ALL messages being transmitted

Asymmetric cryptography

2 keys are used:

• 1 public key - shared openly, used to encrypt

• 1 private key - key secret, used to decrypt

Usually used for transferring data across a more public network (Internet, Cloud)

Advantages (asymmetric cryptography)

• Solves the secure key exchange issue (symmetric)

• Enables digital signatures to verify authenticity

Disadvantages (asymmetric cryptography)

Requires more complex computation so is slower

II. Digital certificate

Binds public key to an identity (person, organization, device)

• Issued by Certificate Authorities (CAs) after verifying identity

• Done to prove authenticity and establish trust in secure communications