Falsification

What is Document Falsification? (Digital Falsification)

"Falsification" refers to intentionally altering the content of documents or records from their original, authentic state. To protect electronic documents against falsification, digital signatures utilizing public-key cryptography are widely employed.

When transmitting electronic documents securely, the following process typically ensures protection against falsification:

Sender Side

1. A message digest is generated from the document content using a cryptographic hash function.
2. The sender encrypts this message digest with their private key, creating a digital signature.
3. The original document and digital signature are combined and transmitted to the recipient.

Recipient Side

1. The recipient decrypts the digital signature using the sender’s public key, yielding a message digest.
2. The recipient also independently computes the message digest from the received document.
3. The two message digests are compared. If they match, the recipient can verify both the authenticity of the sender and the integrity of the document.

This approach enables recipients to confirm that the sender is indeed the holder of the corresponding private key (establishing sender authenticity) and ensures the document has not been subjected to falsification (protecting data integrity). To reliably verify authenticity, the recipient needs the correct public key, validated through a digital certificate issued by a trusted authority. If the digital signature represents a seal (similar to a physical stamp), then the digital certificate serves as official authorization verifying the legitimacy of that seal.