How does a file hash prove a document hasn't been tampered with?

A cryptographic hash is a fixed-length fingerprint of a file's contents. Any change — even a single character — produces a completely different hash. By comparing a stored baseline hash against the current file's hash, you can determine definitively whether the file has been altered.

What is the difference between MD5, SHA-256, and SHA-512 for document security?

MD5 is fast but has known collision vulnerabilities and should not be used in security-sensitive contexts. SHA-256 is the current standard and appropriate for most document integrity use cases. SHA-512 offers a larger hash space and is used in high-assurance environments where extra margin is required.

Can this tool be used to verify contracts or legal documents before signing?

Yes. Generate a hash of the document before distribution to all parties. If any party later claims the document was altered, the hash provides technical evidence of the file's original state.

Can I hash confidential documents safely?

Files are processed server-side and held in temporary storage only for the duration of hashing. They are not retained after the session ends. For highly sensitive materials, review Deliteful's privacy policy before uploading.

Is the checksum report admissible as evidence of document integrity?

This depends on jurisdiction and context. Hash values are widely used as technical evidence of file integrity in legal and regulatory proceedings, but consult qualified legal counsel for advice specific to your situation.

Detect Document Tampering with Cryptographic Hash Verification

Document security teams need more than access controls — they need a way to prove a document's contents haven't changed after it left custody. Deliteful's File Hash Checker generates MD5, SHA-1, SHA-256, and SHA-512 checksums that serve as tamper-evident fingerprints for any uploaded file.

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In document security workflows, integrity verification fills the gap between access logging and content auditing. Access logs tell you who opened a file; a checksum tells you whether the file was altered. This distinction matters for contract management, evidence handling, regulated document distribution, and any scenario where a recipient could dispute the authenticity of a document they received.

Deliteful's checksum report lists each file's hash values in a plain-text format that is easy to store, email, or attach to a chain-of-custody record. Multiple algorithms run in a single pass — SHA-256 for current-standard integrity, MD5 for legacy system compatibility, SHA-512 for high-assurance use cases. Supported formats include PDF (300MB), DOCX (50MB), images, and more, with batch processing up to 50 files or 2GB.

How it works

1
Sign in with Google
Create your free Deliteful account — takes under a minute with Google OAuth.
2
Upload the documents to fingerprint
Add PDFs, DOCX files, images, or other supported formats you need to verify.
3
Select your algorithms
Enter sha256, sha512, or md5 as needed — or leave blank to default to SHA-256.
4
Download the checksum report
Receive a plain-text report with each file's computed hash values.
5
Store checksums as tamper-evident baseline
Retain the report alongside the document or in your security log as proof of original file state.

Frequently asked questions

How does a file hash prove a document hasn't been tampered with?: A cryptographic hash is a fixed-length fingerprint of a file's contents. Any change — even a single character — produces a completely different hash. By comparing a stored baseline hash against the current file's hash, you can determine definitively whether the file has been altered.
What is the difference between MD5, SHA-256, and SHA-512 for document security?: MD5 is fast but has known collision vulnerabilities and should not be used in security-sensitive contexts. SHA-256 is the current standard and appropriate for most document integrity use cases. SHA-512 offers a larger hash space and is used in high-assurance environments where extra margin is required.
Can this tool be used to verify contracts or legal documents before signing?: Yes. Generate a hash of the document before distribution to all parties. If any party later claims the document was altered, the hash provides technical evidence of the file's original state.
Can I hash confidential documents safely?: Files are processed server-side and held in temporary storage only for the duration of hashing. They are not retained after the session ends. For highly sensitive materials, review Deliteful's privacy policy before uploading.
Is the checksum report admissible as evidence of document integrity?: This depends on jurisdiction and context. Hash values are widely used as technical evidence of file integrity in legal and regulatory proceedings, but consult qualified legal counsel for advice specific to your situation.

Create your free Deliteful account with Google and start generating tamper-evident checksums for your most sensitive documents.