PDF Signature Checker
Verify the signatures of a PDF file to determine whether the contents have been altered since signing
Drag & drop your PDF file here, or click to browse
Supports PDF files with digital signatures
About PDF Digital Signatures
PDF digital signatures are a type of electronic signature that uses cryptography to ensure document authenticity and integrity. When a PDF is digitally signed, a unique fingerprint (hash) of the document is created and encrypted with the signer's private key.
Key aspects of PDF digital signatures:
- Document Integrity: Any change to the document after signing will invalidate the signature
- Signer Authentication: Digital certificates verify the identity of the signer
- Non-repudiation: Signers cannot easily deny their signature, as it requires their private key
- Timestamping: Provides proof of when the document was signed
Common Use Cases:
- Legal documents and contracts
- Financial statements and reports
- Government forms and applications
- Medical records and prescriptions
- Technical documentation and certification
It's important to note that PDF signatures can be configured in different ways. Some signatures allow specific types of changes after signing (like form filling), while others lock the entire document. This tool checks if the document has been modified in ways not permitted by the signature.