diff --git a/files/en-us/glossary/digital_signature/index.md b/files/en-us/glossary/digital_signature/index.md new file mode 100644 index 000000000000000..017da3c86d5e564 --- /dev/null +++ b/files/en-us/glossary/digital_signature/index.md @@ -0,0 +1,29 @@ +--- +title: Digital signature +slug: Glossary/Digital_signature +page-type: glossary-definition +--- + +{{GlossarySidebar}} + +A **digital signature** is an object that can be used to {{glossary("authentication", "authenticate")}} the author of a document or message. + +Digital signatures are usually based on {{glossary("public-key cryptography")}}, in which a key is created as a pair of keys, with the property that, if some input is encrypted with one key, it can only be decrypted with the other key, and vice versa. + +The creator of the key pair makes one of the keys public and keeps the other one private. To sign a document, the key pair's owner creates a {{glossary("hash")}} of the document and encrypts it with the private key. + +The document and signature are sent to the verifier, who hashes the document, retrieves the public key, and decrypts the signature: if this matches the hash, then the signature has been verified, and the verifier can be confident that it was created by an entity with access to the private key. + +The security of a digital signature system depends (among other things) on: + +- The private key's owner keeping it safe: if other entities can access the private key, they can impersonate the owner. + +- The public key used by the verifier being the genuine counterpart of the owner's private key: if an attacker could trick the verifier into trusting the wrong public key, they could impersonate the owner. + +Verifiers often use {{glossary("digital certificate", "digital certificates")}} to check that public keys are genuine. + +## See also + +- {{glossary("Digital certificate")}} +- {{glossary("Hash")}} +- {{glossary("Public-key cryptography")}}