S4 Ledger anchors only SHA-256 hashes to the XRP Ledger. No documents, filenames, part numbers, serial numbers, PII, CUI, or classified information ever touches the blockchain.
A SHA-256 hash is a one-way mathematical fingerprint. It cannot be reversed to recover the original data. Even knowing the hash, an attacker cannot determine what was hashed.
- 64-character SHA-256 hash string
- XRPL transaction metadata (timestamp, fee, memo field)
- Original documents, files, or records
- Part numbers, NSNs, serial numbers
- Personnel names, SSNs, or PII
- Contract numbers or dollar amounts
- Classified or CUI-marked data
- Any identifiable defense information
- Collision resistance: No two different inputs have ever been found to produce the same SHA-256 hash. The probability is approximately 1 in 2^128 — computationally infeasible.
- Pre-image resistance: Given a hash, it is computationally infeasible to find the original input.
- NIST approved: SHA-256 is approved by NIST (FIPS 180-4) for federal information processing.
- Industry standard: Used by Bitcoin, TLS certificates, code signing, and DoD systems.
- Consensus: XRPL uses the XRP Ledger Consensus Protocol (not proof-of-work or proof-of-stake). Validators agree on transaction ordering without mining.
- Decentralized: 150+ validators operated by universities, exchanges, and independent operators worldwide.
- Uptime: 99.99%+ since 2012. No rollbacks, no chain reversals.
- Finality: Transactions are final in 3-5 seconds. Once anchored, a hash cannot be altered or removed.
- Immutability: Ledger history is cryptographically linked. Altering a past transaction would require rewriting the entire chain — computationally impossible.
- TLS 1.3: All connections to XRPL nodes use TLS 1.3 encryption
- Key management: Wallet seeds are never stored by S4 Ledger servers. Keys remain with the user.
- No telemetry: The SDK does not phone home, collect analytics, or transmit usage data
- Open source: Full source code available for audit
- Dependency management: Minimal dependencies —
xrpl-pyandcryptography(both audited, widely-used libraries) - Input validation: All inputs are sanitized before hashing. Invalid data types are rejected.
| Control Framework | S4 Ledger Alignment |
|---|---|
| NIST 800-171 | Zero CUI on-chain. Hash-only architecture ensures no controlled unclassified information is exposed. |
| CMMC Level 2+ | Compatible with CMMC practices. S4 Ledger supplements existing controls with integrity verification. |
| DFARS 252.204-7012 | No covered defense information is stored, processed, or transmitted on-chain. |
| NIST 800-53 (AU family) | Provides immutable audit trail (AU-3, AU-6, AU-10, AU-11). |
| FedRAMP | Planned for Phase 5 roadmap. |
| Threat | Mitigation |
|---|---|
| Data exfiltration via blockchain | Impossible — only irreversible hashes are stored |
| Hash collision (fake record passes verification) | SHA-256 collision probability: ~1 in 2^128 |
| XRPL ledger tampering | Requires compromising 80%+ of validators simultaneously |
| Man-in-the-middle on SDK calls | TLS 1.3 encryption on all XRPL connections |
| Wallet compromise | Users control their own keys; S4 Ledger never stores seeds |
| Supply chain attack on SDK | Minimal dependencies, pinned versions, hash-verified packages |
If you discover a security vulnerability in S4 Ledger:
- Email: [email protected]
- Do not open a public GitHub issue for security vulnerabilities
- Include: Description of the vulnerability, steps to reproduce, potential impact
- Response time: We will acknowledge within 48 hours and provide a resolution timeline within 7 days
We follow coordinated disclosure practices. Reporters will be credited unless they request anonymity.
In the event of a security incident:
- Affected services are isolated immediately
- Impact assessment within 4 hours
- User notification within 24 hours if data is affected
- Post-incident report published within 30 days
- Remediation deployed and verified
© 2026 S4 Ledger. Charleston, SC.