Digital Signature

A digital signature is a cryptographic proof created by hashing data and signing the hash with a private key. Anyone with the matching public key can verify the signer's identity and that the data is unchanged.

Why it matters

Signatures provide authenticity, integrity and non-repudiation. They underpin TLS certificates, software updates, signed emails, DKIM and JWTs. A changed byte anywhere in the data makes verification fail, so tampering is detectable.

Example

A software vendor signs an installer. Your operating system verifies the signature with the vendor's public key before running it, and shows a warning if the file was modified or the signer is unknown.

Common mistakes

• Confusing it with an image of a handwritten signature.
• Signing without protecting the private key, so others can forge signatures.
• Verifying the signature but not checking that the public key truly belongs to the claimed signer.

Related

• Public key
• Private key
• Hashing
• DKIM
• टूल: SSL checker

यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.