Generate a local RSA or EC test key pair
Generate an RSA (2048, 3072 or 4096) or EC (P-256 or P-384) key pair with Web Crypto and verify a synthetic signature.
- Runs in your browser
- No upload
- Check before download
Generate an RSA (2048, 3072 or 4096) or EC (P-256 or P-384) key pair with Web Crypto and verify a synthetic signature. Save genuine JWK, SPKI and, if you ask for it, PKCS8 files. Private exports require the checkbox; no key is stored automatically or certified suitable for production.
Local processing and secrets
Inputs stay in this tab and its terminable worker. No input, secret, filename or contact is sent to a service, stored, logged or measured. Fixed parser/code/metadata assets load from this site only for the selected job. Sensitive inputs have no original-backup button; private exports require an explicit choice and download. Reset or leave the page to release the references; memory erasure cannot be guaranteed by JavaScript. Test-secret fields accept multiple lines and are visible in this tab.
Resource limits
At most1MiB combined UTF8 string/file bytes,200,000 UTF16 units per string,1,000 batch rows,32 nesting levels and20,000 input nodes; at most4MiB of export files and20 files. Every run ends or is terminated after15 seconds. CSR DER≤64KiB; DKIM headers≤128KiB/1,000 fields/8KiB per field and20,000 mail lines. TypeScript≤20 files,25,000 characters each/100,000 total,20,000 tokens per file,128 syntax levels,100,000 AST nodes and1,000 diagnostics. These are application limits, not a total worker-heap cap. CSV is UTF8, quoted, comma/CRLF, with formula-prefix protection and a declared null marker.
Use and verify the result
- Input, one record per line
Select an RSA or EC test profile, then generate a local pair or import supported private JWK/PKCS8 material. Turn on private export only when you really need it.
- Declared profile
Generate EC P-256 and run the synthetic pair check. The public SPKI PEM and the public JWK describe the same public key, and pairVerified reports the sign/verify check.
- Local processing and secrets
Reopen the public files with the test consumer you plan to use. Keep the private PKCS8 or private JWK separate and secret. Public downloads don't need private export.
Questions about this local profile
What does this result mean?
The synthetic signature only verifies that the generated or imported pair matches. It doesn't certify identity, suitability for production or safe custody of the key.
How do I resolve rejected or missing input?
Match the import profile and the key algorithm. Encrypted or incompatible material is rejected. Don't paste a production secret to troubleshoot a test.
What are the limits of this tool?
Browser-local test material with a 15 s job deadline. Nothing is stored automatically, and memory isn't guaranteed to be erased, so closing or resetting is not secure destruction.
Original dependency notices for this local security-tool family, including its TypeScript compiler and libraries. Original license and copyright notices