Glossary term · H
Hashing (hash)
Definition
Hashing is a cryptographic operation that transforms a document of any size into a digital fingerprint of fixed size, called a "hash". Any modification, however minor, to the document produces a completely different hash, thus guaranteeing the integrity of the file. Digital signature relies on the encryption of this hash with the signatory''s private key.
Frequently asked questions
What is hashing in cryptography?
Hashing is an operation that turns a document of any size into a fixed-size digital fingerprint, called a hash.
What is hashing used for in an electronic signature?
A digital signature relies on encrypting this hash with the signer's private key, which lets anyone verify both the signer's identity and the document's integrity.
Does a minor change to a document change its hash?
Yes — any change, however small, produces a completely different hash, which is what guarantees the integrity of the signed file.
Is hashing alone enough to secure an electronic signature?
No — the hash guarantees the document's integrity, but it's encrypting it with the signer's private key (the digital signature) that provides proof of identity and legal value.
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