Difference: Encapsulation, Decapsulation, Encryption, and Decryption

Encapsulation and Decapsulation are specifically related to ONLY sending a symmetric key to a recipient.

Encapsulation

• A sender generates a symmetric key.
• The sender encrypts the symmetric key using a public key of the recipient.
• The encrypted symmetric key (ciphertext) is sent to the recipient.

Decapsulation

• The recipient uses their private key to decrypt the ciphertext.
• The decrypted ciphertext reveals the original symmetric key.
• This process allows the sender and recipient to establish a shared secret key (the symmetric key) securely over a potentially insecure channel. Once the symmetric key is established, it can be used to encrypt and decrypt actual data using a symmetric encryption algorithm.

Key points to remember

• Encapsulation and Decapsulation are essential components of Key Encapsulation Mechanisms (KEMs).
• They are used to securely exchange symmetric keys over public channels.