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PDF signature validation vs SHA-256: two different checks
A matching SHA-256 value answers a file-content question. It is not the same operation as validating a certificate-based signature in a document. Identify which check you were asked to perform before treating a result as evidence of something else.
A comparison by the maker of DocAISign, based on official product documentation. We have not independently tested every competitor or verified every plan. Product names belong to their owners.
DocAISign paid checkout is not currently enabled. Self-signing is free; check your available sends and the Pricing page before planning a request.
Skribble separates signing and validation APIs
Skribble’s API overview lists signing APIs and a Validation API for digitally signed documents and certificates, including PDF and XML validation and reports. It also labels API versions as stable or preview. Check the current version and supported validation scope before building an integration.
A fingerprint compares exact file content
DocAISign’s audit includes SHA-256 fingerprints for relevant file versions. Compare the completed PDF with the Signed PDF entry to check that copy. This does not validate a digital certificate, establish who controlled an email address or decide whether an organisation accepts the signature method.
A later compression, annotation or resave can change bytes even when the page looks similar. Preserve the completed original rather than expecting an old hash to describe a processed copy.
A visible mark is another part of the document
A typed or drawn signature mark shows what appears on the page. Its appearance alone does not tell you whether a certificate-based signature exists. Read the product’s actual method and the recipient’s requirement instead of judging from a handwriting style.
DocAISign provides electronic marks and an audit record, not certificate-based digital signatures or formal identity verification. It does not provide a certificate-validation service.
Ask what result is actually required
- Is the task to compare a copy with a recorded fingerprint?
- Is a certificate-based signature expected in the source document?
- Which validator and report does the requesting organisation accept?
- Does the check concern the original completed file or a later copy?
- Who will review an uncertain or failed result?
Treat a failed check as something to investigate
First confirm the document version, selected file and matching record. Do not call a hash mismatch proof of fraud, or interpret an unfamiliar validation result as a legal conclusion. Keep the original files while asking the responsible sender or organisation for clarification.
If you use an online validator, check its handling of documents before submitting non-public content. A local fingerprint comparison avoids uploading a file elsewhere, but still answers only the narrower content question.
Keep the evidence with its context
Store the completed original, corresponding audit and any required validation report under a clear reference. Record which check was performed rather than labelling every outcome simply verified. If the required signing method differs from the one used, arrange the correct workflow rather than attempting to add assurance by changing a filename.