#22unit 1technology solutions

Digital Envelope

Wrapping data with symmetric and public key methods.

3D Learning World

Interactive Visualizations

Topic Diagrams

How a digital envelope works

Symmetric key encrypts the large document; the recipient's public key encrypts the symmetric key.

encrypt with symmetric keyencrypt with recipient's public keydecrypt envelope with private key → recover symmetric keydecrypt document with symmetric keyLarge documentSymmetric keyEncrypted doc…Recipient's p…Digital envel…Recipient's p…Decrypted doc…

A digital envelope wraps a message in two layers. First, the large document is encrypted with a fast symmetric key. Second, the symmetric key itself is encrypted with the recipient's public key, forming the digital envelope. The encrypted document and the envelope are sent together. The recipient uses his or her private key to decrypt the envelope and recover the symmetric key, then uses the symmetric key to decrypt the document. This combines the speed of symmetric encryption with the secure key exchange of public key encryption.

Explanation: A digital envelope wraps a message in two layers. First, the large document is encrypted with a fast symmetric key. Second, the symmetric key itself is encrypted with the recipient's public key, forming the digital envelope. The encrypted document and the envelope are sent together. The recipient uses his or her private key to decrypt the envelope and recover the symmetric key, then uses the symmetric key to decrypt the document. This combines the speed of symmetric encryption with the secure key exchange of public key encryption.