A digital signature is used to verify that a message or file is genuine and has not been changed. It proves the identity of the sender and ensures the data is authentic.

• The sender creates the message
• A hash (unique code) is generated from the message
• The hash is encrypted using the sender’s private key, this becomes the digital signature
• The message and signature are sent together
• The receiver:
  • Decrypts the signature using the sender’s public key
  • Generates a new hash from the received message
  • Compares both hashes
• If the hashes match:
  • The message is authentic
  • The message has not been changed

• Uses both private and public keys
• Confirms sender identity
• Ensures data integrity (no changes made)

• Prevents tampering with data
• Provides trust in online communication
• Commonly used in emails, software downloads, and secure transactions