# Public vs Private Blockchain — Implementation Workbook

Version: 1.0
Published: 2026-07-27
Last updated: 2026-07-27
Owner: Rusaka Research
Review frequency: Quarterly

## Decision statement

What decision must this workbook support?

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## Scope and exclusions

In scope:

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Out of scope:

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## Baseline evidence register

| Evidence item | Source | Date | Owner | Verified by | Status |
|---|---|---|---|---|---|
| | | | | | |
| | | | | | |
| | | | | | |

## Assumption register

| Assumption | Rationale | Decision affected | Downside case | Test | Owner | Review date |
|---|---|---|---|---|---|---|
| | | | | | | |
| | | | | | | |

## Options and decision criteria

| Option | Outcome | Feasibility | Cost | Time | Risk | Reversibility | Recommendation |
|---|---:|---:|---:|---:|---:|---:|---|
| | | | | | | | |
| | | | | | | | |

## Implementation plan

| Phase | Entry evidence | Actions | Owner | Control | Exit evidence | Due date |
|---|---|---|---|---|---|---|
| 1. Operations — Public vs Private Blockchain | | During operations, use Public vs Private Blockchain to select an option against use-case-specific criteria. Start with a current asset inventory, data flows, threat model, control evidence, incidents, contracts, and applicable obligations. Name the accountable owner, the evidence reviewer, the decision deadline, and the output that proves this stage is complete. Record exclusions and unresolved questions rather than allowing them to disappear into narrative. The stage closes only when its evidence can be reproduced by someone who did not prepare it. | | | Required output: a weighted decision matrix with sources and sensitivity checks. | |
| 2. Discovery — Public vs Private Blockchain | | During discovery, use Public vs Private Blockchain to select an option against use-case-specific criteria. Start with a current asset inventory, data flows, threat model, control evidence, incidents, contracts, and applicable obligations. Name the accountable owner, the evidence reviewer, the decision deadline, and the output that proves this stage is complete. Record exclusions and unresolved questions rather than allowing them to disappear into narrative. The stage closes only when its evidence can be reproduced by someone who did not prepare it. | | | Required output: a weighted decision matrix with sources and sensitivity checks. | |
| 3. Design — Public vs Private Blockchain | | During design, use Public vs Private Blockchain to select an option against use-case-specific criteria. Start with a current asset inventory, data flows, threat model, control evidence, incidents, contracts, and applicable obligations. Name the accountable owner, the evidence reviewer, the decision deadline, and the output that proves this stage is complete. Record exclusions and unresolved questions rather than allowing them to disappear into narrative. The stage closes only when its evidence can be reproduced by someone who did not prepare it. | | | Required output: a weighted decision matrix with sources and sensitivity checks. | |
| 4. Pilot — Public vs Private Blockchain | | During pilot, use Public vs Private Blockchain to select an option against use-case-specific criteria. Start with a current asset inventory, data flows, threat model, control evidence, incidents, contracts, and applicable obligations. Name the accountable owner, the evidence reviewer, the decision deadline, and the output that proves this stage is complete. Record exclusions and unresolved questions rather than allowing them to disappear into narrative. The stage closes only when its evidence can be reproduced by someone who did not prepare it. | | | Required output: a weighted decision matrix with sources and sensitivity checks. | |
| 5. Scale — Public vs Private Blockchain | | During scale, use Public vs Private Blockchain to select an option against use-case-specific criteria. Start with a current asset inventory, data flows, threat model, control evidence, incidents, contracts, and applicable obligations. Name the accountable owner, the evidence reviewer, the decision deadline, and the output that proves this stage is complete. Record exclusions and unresolved questions rather than allowing them to disappear into narrative. The stage closes only when its evidence can be reproduced by someone who did not prepare it. | | | Required output: a weighted decision matrix with sources and sensitivity checks. | |

## Measures and thresholds

| Measure | Definition | Source | Baseline | Target | Threshold | Owner | Frequency |
|---|---|---|---:|---:|---:|---|---|
| | | | | | | | |
| | | | | | | | |

## Risk and control register

| Risk | Cause | Impact | Preventive control | Detective control | Owner | Residual risk |
|---|---|---|---|---|---|---|
| | | | | | | |
| | | | | | | |

## Review checklist

- [ ] 1. Operating model: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 2. Architecture and integration: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 3. Risk and compliance: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 4. Economics and value: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 5. Delivery sequencing: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 6. Vendor and partner assessment: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 7. Measurement system: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 8. Quality assurance: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 9. Change management: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 10. Documentation: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 11. Scenario analysis: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 12. Security and resilience: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 13. Data governance: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.
- [ ] 14. Capability and resourcing: evidence is linked, ownership is named, exceptions are recorded, and the current decision is clear.

## Approval record

| Role | Name | Decision | Conditions | Date |
|---|---|---|---|---|
| Accountable owner | | | | |
| Subject-matter reviewer | | | | |
| Risk or control reviewer | | | | |

## Authoritative references

- https://ethereum.org/en/developers/docs/ — Authoritative reference 1 for the evidence and standards relevant to Blockchain and Digital Assets. Confirm the current version and applicability before relying on it.
- https://www.bis.org/about/bisih/topics/cbdc.htm?programme=0 — Authoritative reference 2 for the evidence and standards relevant to Blockchain and Digital Assets. Confirm the current version and applicability before relying on it.
- https://www.fatf-gafi.org/en/topics/virtual-assets.html — Authoritative reference 3 for the evidence and standards relevant to Blockchain and Digital Assets. Confirm the current version and applicability before relying on it.

## Related Rusaka resources

- https://www.rusaka.com/resources/comparisons
- https://www.rusaka.com/resources/guides/digital-asset-custody-guide
- https://www.rusaka.com/resources/playbooks/web3-product-playbook
- https://www.rusaka.com/resources/comparisons/monolith-vs-microservices
- https://www.rusaka.com/resources/comparisons/cloud-vs-on-premise-comparison
- https://www.rusaka.com/resources/calculators/blockchain-roi-calculator
- https://www.rusaka.com/resources/guides/blockchain-strategy-guide

## Important limitation

This educational workbook does not replace legal, investment, tax, accounting,
security, clinical, regulatory, or other qualified professional advice. Confirm
current requirements and obtain formal organisational approval where applicable.