Chained custody transition records. Role-scoped tier access from collecting officer through court. Tamper-evident across the pipeline.
Filed · Patent pending
ABT methodology family · variant ABT-L · legal evidence custody
Evidence that proves its own chain without revealing the case
How a cryptographic custody envelope authenticates five handoffs across officer, lab, prosecutor, defense, and court — with each tier seeing only its own record.
US Provisional Patent 64/056,353 · Filed May 4, 2026 · sidratnam.com/abt/
Each custody hand holds its own tier · Transfer is hash-chained · Defense receives its tier directly from the chain — not via prosecution
At the scene, Guerrero constructs the ABT-L envelope for evidence item EV-2024-0441. The envelope includes tiers addressed to each hand in the chain: officer, lab, prosecutor, defense, and court. The collection event is recorded in the hash chain.
Collecting officer
Det. Ines Guerrero
ck_ev0441 — custody root key
Constructs envelope at collection
Signs collection tier
collection envelope →
Registry
Evidence Registry
Witnesses collection event
Hash-chains h_0
Holds no case content
Evidence envelope · EV-2024-0441 · collection
item_idEV-2024-0441
collection_time2024-11-03T14:22:07Z
collecting_officerDet. Ines Guerrero · Badge 4417
scene_location1142 Kessler Ave · Room 3
lab_tier[ encrypted to forensic lab tier key ]
prosecution_tier[ encrypted to prosecution tier key ]
All five tiers are constructed at collection time. Each tier is sealed to the key of its intended custodian. The officer's collection tier is readable by the officer's credential. The lab tier is sealed until the lab receives the item and its key decrypts it. No party sees another party's tier — even if they share the same physical evidence storage system.
Transfer to forensic lab — second hand in the chain
Guerrero transfers EV-2024-0441 to the forensic lab. The transfer event is hash-chained as h_1. The lab decrypts its tier and records analysis results.
Collection
Det. Guerrero h_0
→
Lab
Forensic Lab h_1
→
Prosecution
— pending —
→
Defense
— pending —
→
Court
— pending —
Lab tier · EV-2024-0441 (decrypted by lab tier key)
item_idEV-2024-0441
received2024-11-03T16:45:00Z · Lab Tech Chen
analysis_typeFingerprint + DNA extraction
fingerprint_resultpartial match · 9 points · reference: pending
The lab cannot read the officer's collection tier. The lab receives its own tier — which contains the fields relevant to its function — and nothing more. It cannot access the collection location notes or the officer's situational observations. Each tier is scoped to its custodian's institutional function.
Transfer to prosecution — third hand
The lab completes analysis and transfers EV-2024-0441 to the prosecution. The prosecution receives its tier, which includes lab results and the full collection record.
The prosecution tier does not include prosecution strategy notes that appear only in prosecution's working files. The tier contains the evidentiary record — not privileged work product. The defense tier is separately sealed and cannot be altered by prosecution. The chain extends to defense directly from the registry — prosecution is not the routing node for defense disclosure.
Defense disclosure — Brady material via chain, not via prosecution
The defense receives its tier key from the registry directly. The defense tier was constructed at collection time and has been sealed since. Prosecution cannot have altered it. This satisfies Brady without routing through the prosecution's discretion.
The defense tier was sealed at collection — before the prosecution ever held the item. Prosecution cannot have modified the defense-tier contents, because the defense tier was encrypted at the scene to a key prosecution does not hold. Brady disclosure is satisfied structurally: the defense receives what was recorded at collection and lab, without relying on prosecution's voluntary disclosure.
Court submission — court tier and full chain
The court receives the evidence item with the full chain hash record. The court tier decrypts to a summary authenticated by every prior hand. The court can verify the unbroken chain without reconstructing each tier's full content.
Court tier · EV-2024-0441
item_idEV-2024-0441
case_numberCR-2024-8841
chain_summary5 hands · h_0 through h_4 · all verified
Any party can verify the complete chain by checking the hash sequence. A gap in the chain — an unrecorded transfer, a skipped hand — produces a hash verification failure. There is no plausible deniability for a transfer that broke the chain.
A broken chain is immediately detectable. If evidence passed through an unrecorded hand — a borrowed item, an unauthorized access — the next legitimate hash would fail to verify against the chain. There is no way to introduce an unrecorded transfer without producing a detectable integrity failure. The chain authenticates itself; no testimony about custody is required beyond the hash record.