Hash Chain Verification

Verify the integrity of your audit log using cryptographic hash chain verification to detect any tampering or modifications.

What is Hash Chain Verification?

Logproof uses a cryptographic hash chain to ensure the integrity of your audit log. Each event contains a hash that is calculated using SHA-256 based on:

The hash of the previous event
The current event's data (timestamp, action, actor, target, metadata)

This creates a tamper-proof chain where any modification to a past event will break the chain and be immediately detectable. If any event is altered, deleted, or inserted, the hash chain verification will fail at that point.

How it works: Event hash = SHA-256(previous_hash + event_data). This ensures that each event cryptographically depends on all events that came before it.

Verify Endpoint

GET /verify

Verify the integrity of your entire audit log hash chain.

Required Scope

verify

Response

Field	Type	Description
`status`	string	Verification status: `valid` or `broken`
`events_checked`	integer	Total number of events checked
`first_event_id`	string	ID of the first event in the chain
`last_event_id`	string	ID of the last event in the chain
`broken_at_event_id`	string\|null	ID of the event where the chain broke (null if valid)

Examples

curl -X GET "https://logproof.de/v1/verify" \
  -H "Authorization: Bearer YOUR_API_KEY"

<?php

$client = new \GuzzleHttp\Client();

$response = $client->get('https://logproof.de/v1/verify', [
    'headers' => [
        'Authorization' => 'Bearer YOUR_API_KEY',
    ],
]);

$data = json_decode($response->getBody(), true);

if ($data['data']['status'] === 'valid') {
    echo "Hash chain is valid!\n";
    echo "Checked {$data['data']['events_checked']} events\n";
} else {
    echo "Hash chain is broken at event: {$data['data']['broken_at_event_id']}\n";
}

const axios = require('axios');

async function verifyHashChain() {
  try {
    const response = await axios.get('https://logproof.de/v1/verify', {
      headers: {
        'Authorization': 'Bearer YOUR_API_KEY'
      }
    });

    const { status, events_checked, broken_at_event_id } = response.data.data;

    if (status === 'valid') {
      console.log('Hash chain is valid!');
      console.log(`Checked ${events_checked} events`);
    } else {
      console.log(`Hash chain is broken at event: ${broken_at_event_id}`);
    }
  } catch (error) {
    console.error('Verification failed:', error.message);
  }
}

verifyHashChain();

import requests

headers = {
    'Authorization': 'Bearer YOUR_API_KEY'
}

response = requests.get(
    'https://logproof.de/v1/verify',
    headers=headers
)

data = response.json()['data']

if data['status'] == 'valid':
    print(f"Hash chain is valid!")
    print(f"Checked {data['events_checked']} events")
else:
    print(f"Hash chain is broken at event: {data['broken_at_event_id']}")

Example Response (Valid Chain)

{
  "data": {
    "status": "valid",
    "events_checked": 15234,
    "first_event_id": "evt_01H2X3Y4Z5A6B7C8D9E0F1G2",
    "last_event_id": "evt_01H8X3Y4Z5A6B7C8D9E0F1G2",
    "broken_at_event_id": null
  }
}

Example Response (Broken Chain)

{
  "data": {
    "status": "broken",
    "events_checked": 15234,
    "first_event_id": "evt_01H2X3Y4Z5A6B7C8D9E0F1G2",
    "last_event_id": "evt_01H8X3Y4Z5A6B7C8D9E0F1G2",
    "broken_at_event_id": "evt_01H5X3Y4Z5A6B7C8D9E0F1G2"
  }
}

Important: A broken hash chain indicates that your audit log may have been tampered with. Contact support immediately if you detect a broken chain.

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