Hybrid Cryptography
Hybrid cryptography is where we use the advantages of both symmetric and asymmetric key cryptography.
4 slides · 1 min read · Domain 3
As you remember, symmetric is fast but problematic in the way of key distribution. Asymmetric, on the other hand, is slow but solves the problem of key distribution. Why not use both for what they are each good at?
This is referred to as a hybrid cryptography system. A hybrid system operates as shown.
Text on this slide
Sender
Plaintext Large Message Encryption Using Symmetric Key
Symmetric Key SK
Encryption
Symmetric Key
Public Key of Receiver Encrypted Message
Encrypted Symmetric Decryption Using Symmetric Key
Symmetric Key SK
Decryption
Symmetric Key
Private Key of Receiver Receiver
Plaintext Message
The message itself is encrypted with a "symmetric key" - or "SK" for short and is sent to the recipient.
To allow the recipient to have the SK required for decryption, it is encrypted with the public key of the recipient and sent to the recipient. The recipient then decrypts the SK withtheir private key that no one else has. This provides the SK to the recipient only, which can then be used to decrypt the message.