Use checksums to verify an accounting document transfer

When accounting attachments move between storage systems or providers, matching folder names does not show that every file arrived unchanged. Create a transfer manifest from the approved source and compare it with the destination. The manifest should identify each file, its size, its intended destination, and the transaction or document record it supports.

A cryptographic checksum, or digest, adds a way to compare file content. NIST's Secure Hash Standard describes algorithms whose digests can detect changes to messages. Ask the technical owner to use an appropriate supported algorithm, such as SHA-256, consistently at both ends. Record the algorithm with the result so future comparisons use the same method.

A matching digest supports a conclusion about the transferred bytes. It does not establish that the original invoice was genuine, that the purchase was approved, or that the source archive contained every required record. Those questions still need their own evidence.

Compare the complete manifest rather than only the total storage size. Two missing documents can be obscured by an unrelated large file. Check missing files, unexpected files, duplicate destinations, and changed content separately. Also verify the relationships between attachments and accounting transactions; intact files linked to the wrong invoice remain a failed handoff.

Preserve the source version before investigating a mismatch. A PDF may have been intentionally converted, compressed, annotated, or redacted. Those operations can change its digest even when a reviewer considers the visible document similar. Decide whether the destination requires the exact original or an approved derivative, and label the relationship between them.

For an unexplained difference, repeat the comparison against the retained source and investigate the transfer path. Do not overwrite the only original simply to make the destination match. Keep the discrepancy open until the owner accepts a corrected transfer or a documented transformation.

Keep the accepted manifest in a company-controlled location with access appropriate to its contents. File names and transaction identifiers can themselves reveal sensitive information. Protect the comparison record from casual alteration, and identify who approved any exceptions. A freely editable manifest beside an equally editable archive offers limited evidence about what was transferred originally.

Perform a small retrieval test after the byte-level comparison. Open a representative invoice, statement, signed agreement, and any unusual format the archive must support. Verify readable pages and the intended accounting reference. A checksum can confirm an unchanged file that was already unreadable at the source.

Retain the accepted source snapshot until the transfer's completion and applicable retention decisions are settled. If the source system will close, resolve missing items while it remains available. The handoff should finish with a complete item register, explained transformations, successful authorized retrieval, and a named owner for later archive questions.