CRYPTOGRAPHIC VERIFICATION

Deterministic primality.
Signed certificates.

C5 provides deterministic primality testing and signed certificates for security-critical applications — take the RSA, ECC, or Diffie-Hellman parameters you already hold and get back checkable, tamper-evident proof.

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Built for production security
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Deterministic testing

No probabilistic guessing. Deterministic results across the full integer range — every verdict is provable, not statistical.

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Signed certificates

Every verification produces an HMAC-SHA256 signed certificate. Auditable. Traceable. Tamper-evident. Attach to any key-generation workflow.

Sub-second response

127-bit verification in under 600ms. 256-bit prime generation in under 2 seconds. Fast enough for real-time key generation.

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NIST compliance

Security assessments aligned with NIST SP 800-57. RSA, ECC, and DH key sizes evaluated against minimum security requirements. Compliance status on every certificate.

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API-ready

One module. Import and call. Integrates with any crypto pipeline — and you can drive it directly from the console below.

Security assessment

RSA-2048

112-bit equivalent security. NIST compliant. ✓

RSA-4096

140-bit equivalent security. NIST compliant. ✓

ECC-256

128-bit equivalent security. NIST compliant. ✓

ECC-384

192-bit equivalent security. NIST compliant. ✓

Console

Drive C5 directly. Paste your key, then press SEND on an endpoint. Responses come back raw.

Your key is held in memory only — never stored in this file, sent only to the base URL above. Paste your key, then press SEND on an endpoint.
Calls go to the base URL with your X-API-Key. C5 routes are editable on each card — confirm the path for your build; if a call 404s, fix the route and re-send. If a call is blocked by CORS, run it from a page served by the same origin as the base URL.