🔐 Certificate CRT Decoder
Decode and analyze X.509 SSL/TLS certificates. Extract detailed information from CRT, PEM, or CER certificate files including validity dates, issuer details, subject information, and public key data. All processing is done locally in your browser.
📄 Certificate Input
Supported: .crt, .cer, .pem
📋 Decoded Certificate
Decoded certificate information will appear here...
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About Certificate CRT Decoder
This tool helps you decode and analyze X.509 SSL/TLS certificates in various formats. Simply paste your certificate or upload a file to extract comprehensive information about the certificate.
Features:
- Multiple Format Support: Works with PEM, CRT, CER, and other common certificate formats
- Complete Certificate Details: View version, serial number, signature algorithm, and more
- Issuer & Subject Info: Extract detailed information about certificate issuer and subject
- Validity Period: Check certificate validity dates and expiration status
- Public Key Information: View public key algorithm, size, and modulus
- Extensions: Display certificate extensions including SANs, key usage, and policies
Supported Certificate Formats:
- PEM: Base64 encoded certificates with BEGIN/END markers
- CRT: Common certificate file format (usually PEM encoded)
- CER: Certificate file (can be PEM or DER encoded)
Common Use Cases:
- Verify certificate details before installation
- Check certificate expiration dates
- Validate issuer information
- Inspect Subject Alternative Names (SANs)
- Debug SSL/TLS certificate issues
- Extract public key information
Privacy & Security:
All certificate decoding is performed entirely in your browser using JavaScript. No certificate data is transmitted to any server, ensuring complete privacy and security of your sensitive information.