Authentication with Digital Signatures

• A and B can use digital signatures to expose X.

  • A produces a hash, or fingerprint, of the message and encrypts it with A's private key.
  • B decrypts it with A's public key and can recompute the same hash on the message.
  • If it decrypts and has the same hash then
    • It must have been written by A
    • It could not have been changed since being written.