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Tamper with an audit record.
Watch the chain break.

Below are five AI hiring decisions logged into a SHA-256 hash chain — the kind of per-event record the EU AI Act Article 12 requires. Edit any score, or hit “Tamper this record”. The verifier runs live in your browser and shows exactly where the chain stops matching.

Chain verified. All 5 decisions hash-match — no tampering detected.
  1. #0EVT_8c2f0a1b
    verified

    Resume screen · Senior Backend Engineer

    candidate #A-4471

    Rationale7 yrs distributed-systems experience; matched 9 of 11 required skills.

    prev_hash
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    entry_hash
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  2. #1EVT_9d1a3c5f
    verified

    Resume screen · Senior Backend Engineer

    candidate #A-4472

    Rationale4 yrs experience; matched 6 of 11 required skills; no on-call history.

    prev_hash
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    entry_hash
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  3. #2EVT_b4e0d8a2
    verified

    Phone-screen ranking · Senior Backend Engineer

    candidate #A-4471

    RationaleStrong system-design answer; clear communication; advanced to onsite.

    prev_hash
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    entry_hash
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  4. #3EVT_c5f10e93
    verified

    Phone-screen ranking · Senior Backend Engineer

    candidate #A-4472

    RationaleSolid fundamentals; one architecture gap; advanced to onsite.

    prev_hash
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    entry_hash
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  5. #4EVT_d7a92f04
    verified

    Final shortlist · Senior Backend Engineer

    candidate #A-4471

    RationaleHighest combined score across screen + onsite; ranked #1 of 12.

    prev_hash
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    entry_hash
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    The chain head. Tamper an earlier record and watch everything below it break.

Each block’s entry_hash is SHA-256 over the decision data plus the previous block’s hash. Change one field and that block’s hash stops matching — and because every later block commits to it, the break cascades forward. That is tamper-evidence: you cannot quietly rewrite history.

This is what your AI’s audit trail looks like.

Praxa logs every decision your high-risk AI makes into a chain exactly like this one — verifiable by an auditor without a Praxa account. Free for 10,000 decisions a month.