Encryption

Encryption

The process of converting of data into an unreadable format.

Plain Text

Data before applying encryption.

Cipher Text

Data after applying encryption.

Key Encryption:

• To ensure a message is authentic.

• To ensure a message isn’t altered during transmission.

• To ensure that only the intended receiver can understand the message.

• To ensure that neither send nor receiver can deny involvement in the transmission.

Public Key

A public key is shared. It is used to encrypt data so that it can be decrypted with its matching private key.

Private Key

A private key is never shared. It is used to decrypt data that was encrypted with its matching public key.

Symmetric Encryption

A single key is used for both encryption and decryption. The key is shared between the sender and the receiver.

Disadvantages:

• Key has to be exchanged securely.

• Once compromised, it can decrypt sent and received messages.

• Cannot ensure origin or integrity of data.

Asymmetric Encryption

Two keys are used: public key and private key. The message is encrypted with the public key and decrypted using the matching private key.

Symmetric VS Asymmetric

Security concerns relating to a transmission:

• Confidentiality: Only the intended recipient should be able to decrypt the message.

• Authenticity: Receiver must know who sent the ciphertext.

• Integrity: Message must not be modified during transmission.

• Non-repudiation: Neither the sender nor the receiver should be able to deny involvement in the transmission.

Quantum Cryptography

Quantum Cryptography is used to produce a virtually unbreakable encryption system using the properties of photons.

Advantages:

• More secure.

• Eavesdropping can be detected.

• Longer keys can be used.

• Almost un-hackable.

• Cannot be copied and decrypted at a later time.

Disadvantages:

• Only works for short distances.

• High cost for maintenance and setup.

• Lacks important features like digital signature, certified mail etc.

• High error rate due to being new.

• Polarization of light may be altered during transmission.