What is a digital envelope in the context of hybrid cryptography?

In hybrid cryptography, a digital envelope refers specifically to the encrypted version of the symmetric key that is used for encrypting the actual data being transmitted. Hybrid cryptography combines both symmetric and asymmetric encryption methods to leverage the strengths of each.

Symmetric encryption is generally fast and efficient for data encryption but requires both parties to share the same secret key securely. Asymmetric encryption, on the other hand, uses key pairs (a public key for encryption and a private key for decryption), which provides a means to securely exchange the symmetric key.

In the context of a digital envelope, the symmetric key is generated for encrypting the data, and then this key is encrypted using the recipient’s public key. This creates the digital envelope, which can be securely sent alongside the encrypted data. Upon receiving the envelope, the recipient uses their private key to decrypt the symmetric key and then uses it to decrypt the actual data.

This process ensures that the symmetric key can be shared securely, enabling both effective data confidentiality and integrity. Other choices do not align with this definition and purpose of a digital envelope within hybrid cryptography.