> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rootkey.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# RKP-3 - Hybrid
> On-chain anchoring combined with off-chain processing. Designed for complex enterprise workflows that require both auditability and performance - without compromise on either.
## Overview
**RKP-3 (Hybrid)** is ROOTKey's enterprise-grade data processing protocol, combining the auditability of full on-chain anchoring with the throughput of off-chain processing. It is designed for organisations that cannot afford to sacrifice either - systems requiring both high availability under load and cryptographically verifiable records for regulatory or operational purposes.
In RKP-3, critical metadata and proof-of-existence are anchored on-chain, while large payloads, high-frequency operations, or sensitive content are processed off-chain with cryptographic binding to the on-chain record. The integration model adapts to the data classification and performance requirements defined per vault or operation type.
This protocol is the default recommendation for enterprise document management, multi-party workflows, and compliance-critical platforms operating at production scale.
***
## Architecture Overview
```mermaid theme={null}
flowchart TD
A([Client Application]) -->|HTTPS / JSON| B[ROOTKey REST API]
B --> C{Data Classification}
C -->|Critical metadata · audit events| D[(Polygon Blockchain\nOn-Chain)]
C -->|Large payloads · high-frequency| E[Off-Chain Storage\n+ Cryptographic Binding\nto On-Chain Record]
D & E --> F[Unified API Response]
F --> A
```
The classification layer determines routing based on vault configuration, operation type, and payload characteristics. Both paths are cryptographically linked - the on-chain record contains a hash binding to the off-chain record, ensuring end-to-end integrity across both paths.
On-chain anchors include:
* **Operation type and timestamp**
* **Vault and asset identifiers**
* **SHA-256 hash binding** to off-chain content (where applicable)
* **Version and lineage markers**
***
## Request Limits and Throughput
| Parameter | Value |
| ------------------------------------- | ----- |
| Maximum requests per second | XXX |
| Maximum concurrent operations | XXX |
| Maximum payload size - on-chain path | XXX |
| Maximum payload size - off-chain path | XXX |
| Burst allowance | XXX |
For plan-specific throughput limits, visit [Pricing](/pages/pricing).
***
## Performance Indicators
| Metric | Value |
| -------------------------------- | ------ |
| Average latency - on-chain path | XXX ms |
| Average latency - off-chain path | XXX ms |
| P95 latency | XXX ms |
| On-chain anchoring frequency | XXX |
| Recovery time objective (RTO) | XXX |
| Recovery point objective (RPO) | XXX |
> Latency profile depends on routing - operations taking the on-chain path inherit blockchain confirmation times, while off-chain operations return near real-time. Routing is deterministic based on vault configuration.
***
## Validation Capabilities
| Validation Type | Supported |
| ----------------------------------------- | --------------------- |
| On-chain proof of existence | Yes |
| On-chain proof of integrity (hash match) | Yes |
| Off-chain content verification | Yes (hash comparison) |
| Cross-path integrity binding | Yes |
| Independent third-party verification | Yes |
| Version history and lineage tracking | Yes |
| GDPR-compatible erasure of off-chain data | Yes |
RKP-3 supports **dual-path validation**: verifiers can confirm the on-chain anchor independently, then validate off-chain content integrity by comparing against the bound hash. This provides the same cryptographic guarantees as RKP-1 for the audit layer, with the operational flexibility of RKP-2 for the data layer.
***
## Strengths
* **Enterprise-grade flexibility** - route operations to on-chain or off-chain based on data classification, without changing the API contract
* **Full auditability for critical events** - on-chain anchoring for operations that must be independently verifiable
* **High throughput for volume operations** - off-chain path for high-frequency or large-payload workloads
* **Cryptographic binding across both paths** - integrity is guaranteed end-to-end across the full operation lifecycle
* **GDPR compatibility** - off-chain data is erasable; on-chain metadata does not contain personal data
* **Version and lineage tracking** - supports complex document lifecycle management with full history
* **Multi-party workflow support** - each party can independently verify their segment of a shared workflow
***
## Weaknesses
* **Higher architectural complexity** - requires careful vault configuration and data classification design
* **Mixed latency profile** - operations are not uniformly fast or uniformly slow; predictability depends on routing configuration
* **Storage dependency for off-chain records** - full verification of off-chain content requires retained data
***
## Typical Use Cases
Document creation, approval, versioning, and audit - with on-chain anchoring for critical events and off-chain storage for large files.
Multi-party custody chains with high-frequency sensor data off-chain and key transfer events anchored on-chain for regulatory evidence.
Platforms serving regulated industries - insurance, legal, public sector - where different data types carry different auditability obligations.
Transaction-level records processed off-chain at volume, with settlement and reconciliation events anchored on-chain for audit.
High-volume trial data collected off-chain with critical protocol deviations, consent events, and final submissions anchored on-chain.
Operational data from critical systems where most telemetry is off-chain, but configuration changes and incident events require immutable on-chain records.
***
## Compliance Alignment
| Framework | Alignment |
| ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| **NIS2 Directive** | Strongest alignment - supports integrity, availability, auditability, and resilience obligations across critical entity categories |
| **ISO 27001** *(in progress)* | Aligns with A.8.15 (logging), A.5.33 (protection of records), A.5.36 (compliance), A.8.12 (data leakage prevention) |
| **GDPR** | Compatible by design - off-chain erasure capability with on-chain proof-of-existence preserved |
| **DORA** | Supports digital operational resilience requirements - audit trail, incident logging, third-party risk documentation |
| **eIDAS** | On-chain anchors provide qualified electronic evidence for critical operational events |
| **IEC 62443** | Applicable for OT/IT convergence environments with mixed data classification requirements |
ROOTKey is actively pursuing NIS2 alignment and ISO 27001 certification. Contact us at [contact@rootkey.ai](mailto:contact@rootkey.ai) for the current compliance posture, security documentation, and pending certifications.
***
Access sandbox and live environments immediately. No commitment required.
Work with our engineering team to design your vault configuration and data classification strategy for RKP-3.