Puro.earth Audit Trail Documentation — Verification Chain of Custody

Purpose

This document provides a comprehensive audit trail from sensor measurement through verification to credit issuance for carbon removal credits under the Puro.earth registry. It outlines the requirements for data integrity, timestamp verification, tamper detection, and audit log format, ensuring compliance with the standards set forth by Puro.earth and its integration with Nasdaq's market infrastructure.

Table of Contents

1. [Chain of Custody](#chain-of-custody)

• 1.1 Overview
• 1.2 Data Flow
• 1.3 Data Field Mappings

1. [Data Integrity](#data-integrity)

• 2.1 Data Collection
• 2.2 Data Processing
• 2.3 Data Transmission

1. [Timestamp Verification](#timestamp-verification)

• 3.1 Timestamp Requirements
• 3.2 Synchronization Protocols

1. [Tamper Detection](#tamper-detection)

• 4.1 Methods of Tamper Detection
• 4.2 Alert Mechanisms

1. [Audit Log Format](#audit-log-format)

• 5.1 Log Structure
• 5.2 Log Retention Policy
• 5.3 Access Control

1. [Conformity Assessment Procedures](#conformity-assessment-procedures)

• 6.1 Audit Procedures
• 6.2 Compliance Verification

Chain of Custody

1.1 Overview

The chain of custody (CoC) refers to the process of maintaining and documenting the handling of carbon removal data from the point of measurement to the issuance of carbon credits. Each step in the CoC shall be clearly defined to ensure traceability and accountability.

1.2 Data Flow

The data flow for the carbon removal credits consists of the following stages:

1. Data Collection: IoT sensors collect environmental data.
2. Data Processing: Collected data is processed using certified algorithms.
3. Verification: Data is verified by accredited third-party verifiers.
4. Credit Issuance: Verified data is used for the issuance of carbon credits.

1.3 Data Field Mappings

The following data fields shall be mapped and documented at each stage of the CoC:

| Field Name | Description | Data Type | Example | |-------------------------|----------------------------------------------|----------------|------------------------------| | Sensor_ID | Unique identifier for the IoT sensor | String | "sensor-001" | | Measurement_Timestamp | Timestamp of data collection | ISO 8601 | "2023-10-01T12:00:00Z" | | Measurement_Value | Value of the measurement | Float | 123.45 | | Location | Geographical location of the sensor | String | "Latitude,Longitude" | | Algorithm_Version | Version of the processing algorithm | String | "v1.0.3" | | Verifier_ID | Unique identifier for the verifier | String | "verifier-xyz" | | Verification_Status | Status of the verification | Enum | "Pending", "Approved", "Rejected" | | Credit_Issuance_ID | Unique identifier for the issued credit | String | "credit-abc-123" |

Data Integrity

2.1 Data Collection

Data integrity during the data collection phase shall be maintained through the following requirements:

• IoT sensors shall be calibrated regularly to ensure measurement accuracy.
• Data shall be collected at predefined intervals, specified in the sensor configuration settings.
• All data collected shall be time-stamped at the moment of measurement.

2.2 Data Processing

The processing of data shall adhere to the following standards:

• Only certified algorithms, which have undergone rigorous testing and validation, shall be used for data processing.
• The input and output of the algorithms shall be logged, including the version of the algorithm used.
• Any data transformation applied shall be documented in the processing logs.

2.3 Data Transmission

Data transmission shall comply with the following protocols:

• Data shall be transmitted over secure channels (e.g., HTTPS, TLS) to prevent unauthorized access.
• Data packets shall include checksums to verify data integrity during transmission.
• Transmission logs shall be generated, indicating the timestamp, data packet size, and destination endpoint.

Timestamp Verification

3.1 Timestamp Requirements

All timestamps must adhere to the ISO 8601 format, ensuring consistency and reliability in time representation. The following requirements apply:

• Format: Timestamps shall be represented as YYYY-MM-DDTHH:mm:ssZ.
• Precision: Timestamps shall include at least seconds and may include milliseconds if required by the use case.
• Source: Timestamps shall be generated by an NTP (Network Time Protocol) synchronized server to ensure accuracy.

3.2 Synchronization Protocols

To maintain timestamp accuracy, the following synchronization protocols shall be implemented:

• All devices collecting data shall synchronize their clocks with a central NTP server at least once every hour.
• A fallback mechanism shall be in place to handle NTP server unavailability, ensuring minimal disruption to data collection.

Tamper Detection

4.1 Methods of Tamper Detection

To ensure the integrity of the data collected and processed, the following tamper detection methods shall be employed:

• Hashing: Each data entry shall be hashed using SHA-256 before transmission. The hash shall be stored alongside the data.
• Digital Signatures: Data packets shall be signed using a private key, with the corresponding public key available for verification.
• Anomaly Detection: Machine learning algorithms shall be employed to detect anomalies in data patterns, which may indicate tampering.

4.2 Alert Mechanisms

In the event of detected tampering, the following alert mechanisms shall be in place:

• Automated alerts shall be sent to system administrators upon detection of anomalies or mismatched hashes.
• A tamper incident log shall be maintained, detailing the nature of the incident, timestamp, and any corrective actions taken.

Audit Log Format

5.1 Log Structure

The audit log shall be structured to provide a comprehensive record of all actions taken within the system. The following fields shall be included:

| Field Name | Description | Data Type | Example | |-----------------------|----------------------------------------------|----------------|------------------------------| | Log_ID | Unique identifier for the log entry | String | "log-001" | | Timestamp | Timestamp of the log entry | ISO 8601 | "2023-10-01T12:00:00Z" | | User_ID | Identifier of the user performing the action | String | "user-abc" | | Action_Type | Type of action performed | Enum | "Data Collection", "Processing", "Verification" | | Action_Description | Description of the action | String | "Data collected from sensor-001" | | Status | Status of the action | Enum | "Success", "Failure" |

5.2 Log Retention Policy

Audit logs shall be retained according to the following policy:

• Logs shall be retained for a minimum of 7 years from the date of the last entry.
• Archived logs shall be stored in a secure, immutable format to prevent unauthorized modifications.
• Access to archived logs shall be restricted to authorized personnel only.

5.3 Access Control

Access to the audit logs shall be governed by strict access control policies:

• Role-based access control (RBAC) shall be implemented to restrict access to logs based on user roles.
• All access to audit logs shall be logged, including the user ID, timestamp, and nature of access (read/write).
• Regular audits of access logs shall be conducted to ensure compliance with access control policies.

Conformity Assessment Procedures

6.1 Audit Procedures

To ensure compliance with the outlined requirements, the following audit procedures shall be implemented:

• Internal Audits: Regular internal audits shall be conducted at least annually to assess compliance with data collection, processing, and storage protocols.
• External Audits: An independent third-party auditor shall be engaged every two years to evaluate the overall compliance with Puro.earth standards.
• Audit Checklists: Standardized checklists shall be used during audits to ensure all relevant areas are covered.

6.2 Compliance Verification

Compliance with the standards shall be verified through the following means:

• Documentation Review: All relevant documentation, including data collection protocols, processing algorithms, and audit logs, shall be reviewed during audits.
• Interviews: Key personnel involved in data collection and processing shall be interviewed to assess adherence to established protocols.
• Testing: Randomized testing of data integrity, timestamp accuracy, and tamper detection mechanisms shall be conducted to validate compliance.

Conclusion

This audit trail documentation serves as a comprehensive guide for ensuring compliance with the standards set forth by Puro.earth for carbon removal credits. By adhering to the outlined requirements for chain of custody, data integrity, timestamp verification, tamper detection, and audit log format, organizations can maintain the integrity of their carbon removal data and facilitate trust within the carbon market ecosystem. Compliance with these standards shall be regularly assessed through internal and external audits to ensure ongoing adherence and improvement.