In HEXSSL, we continuously expand our suite of tools supporting administrators, IT specialists, security auditors, and website owners in quickly diagnosing and verifying elements of the SSL/TLS infrastructure.
After CSR Generator, CSR Checker, SSL Checker, and SSL Monitor, another tool joins the package: HEXSSL SSL Decoder.
This is the missing extension on the market – fast, accurate, and capable of processing both PEM and binary DER certificates. The tool performs a full analysis of X.509 structures and presents them in a clear, organized format.
Why did we create the SSL Decoder?
Managing SSL/TLS certificates often requires analyzing a certificate in its raw form – especially during:
- inspection of a certificate received from a CA,
- diagnosis of certification errors,
- security audits,
- verification of public keys, SAN, signature algorithms,
- checking the consistency of data in multi-domain / wildcard certificates,
- analysis of intermediate or self-signed certificates.
Most public decoders support only PEM. HEXSSL goes further – it also decodes DER certificates and raw Base64.
What can the HEXSSL SSL Decoder do?
The tool was designed for full compatibility with X.509 certificates across formats and variants.
1. Automatic format detection
The SSL Decoder recognizes:
- PEM
- PEM without headers (raw Base64)
- binary DER
- certificates in
.crt,.cer,.pem,.der
The tool converts DER → PEM on the fly, eliminating the need to use OpenSSL locally.
2. Detailed certificate structure preview
The tool displays, among others:
- Subject and Issuer (ordered DN),
- validity start and end dates,
- number of validity days,
- serial number (HEX),
- signature algorithm,
- public key type (RSA/EC/DSA),
- key length (bits),
- Subject Alternative Names (SAN),
- raw, normalized PEM.
A fast way to perform technical analysis directly in your browser.
3. Support for DV, OV, EV, wildcard, and multi-domain certificates
HEXSSL does not limit itself to standard DV certificates – the tool correctly analyzes:
- OV/EV certificates,
- multi-domain certificates (SAN),
- wildcard certificates,
- intermediate CA certificates,
- self-signed certificates.
4. Full privacy – data never leaves the server
Decoding is performed locally, in server memory – without logging and without sending certificates to third parties. This is especially important for audits, pre-production tests, and internal certificates.
Why is this tool better than competing solutions?
Most online decoders have limitations:
| Limitation type | Typical tools | HEXSSL SSL Decoder |
|---|---|---|
| DER support | ❌ none | ✔ full support |
| SAN | often partial | ✔ full parsing |
| Public keys | minimal information | ✔ precise type + length |
| Multi-language | varies | ✔ PL / EN / DE |
| Privacy | often external API | ✔ local processing |
HEXSSL creates administrator-grade tools – fast, precise, and compliant with industry standards.
Who is the SSL Decoder for?
✔ Linux/Windows system administrators,
✔ DevOps / DevSecOps professionals,
✔ security auditors,
✔ online store & web service owners,
✔ SSL certificate integrators & resellers,
✔ anyone diagnosing SSL/TLS issues and certificate chains.
If you work with SSL/TLS infrastructure – this tool will significantly reduce your diagnostic time.
How to start?
The tool is available for free on HEXSSL at:
👉 hexssl.com/ssl-decoder/
Just paste a certificate or upload a file. Decoding takes a fraction of a second.
Together with:
HEXSSL builds a complete ecosystem of tools for managing the SSL/TLS certificate lifecycle – from CSR generation, through validation, to auditing and decoding X.509 structures.
SSL Decoder is the best online platform available for fast, precise, and secure certificate analysis.