macOS/Linux

shasum -a 256 filename.jpg

Windows PowerShell

Get-FileHash filename.jpg -Algorithm SHA256

Install

pip install opentimestamps-client

Generate proof

ots stamp filename.jpg

Upgrade (wait for blockchain confirmation)

ots upgrade filename.jpg.ots

Verify

ots verify filename.jpg.ots

Which Files Need OTS?

File Type OTS Required Reason

Public photos (redacted) ✅ Yes Prove tamper-proof

Public videos (redacted) ✅ Yes Same as above

GPS track files ✅ Yes Prove spatiotemporal track

Public hash manifest (.txt) ✅ Yes Prove manifest integrity

Private hash manifest (.txt) ✅ Yes Prove existence

Private original images ❌ No Not on-chain

Only files uploaded to IPFS need OTS

Create Hash Manifest

PUBLIC_COMMON.txt Template：

STProof_FDC_20260420_PUBLIC_COMMON_Hash_OTS

filename.jpg SHA256 xxx… CID bafybei… OTS_CID bafkreif…

PRIVATE_XXX.txt Template：

STProof_FDC_20260420_XXX_PRIVATE_Hash_OTS

filename.jpg SHA256 xxx… filename.jpg.ots SHA256 xxx…

(No CID, original images not uploaded)