SSL Certificate Signing Request Validator
Using the CSR Checker is very simple:
CSR Checker is used in various scenarios for SSL/TLS certificate acquisition and management:
Before submitting the CSR to a Certificate Authority (CA), verify that Common Name (domain name), organization name, and country code are correctly entered. Issuing a certificate with incorrect information can result in costly and time-consuming reissuance.
After generating a CSR using OpenSSL or server management panel, confirm that it contains the expected content. Especially for SANs (Subject Alternative Names) or wildcard certificates, check that multiple domains are correctly included.
Verify compliance with security policies. For example, check if RSA 2048-bit or higher, or ECDSA (Elliptic Curve Cryptography) is being used as required.
When the SSL certificate expiration is approaching and a renewal CSR is generated, verify that the same information (organization name, department name, etc.) as the previous certificate is included.
When different CSRs are generated on multiple web servers or load balancers, identify which CSR is for which server by checking the CSR contents.
When certificate installation errors or browser warnings occur, check if the CSR and certificate contents match. Common Name or SANs mismatches are frequent causes.
When security audits or compliance requirements necessitate reporting the public key algorithm or key length of certificates in use, extract this information from the CSR.
A CSR (Certificate Signing Request) is electronic data submitted to a Certificate Authority (CA) when obtaining an SSL/TLS certificate. The CSR contains information to be included in the certificate (domain name, organization name, location, etc.) and the public key.
A CSR includes the following information:
CSRs are based on public key cryptography:
CSRs can be generated using the following tools:
Example: openssl req -new -newkey rsa:2048 -nodes -keyout server.key -out server.csr
CSRs are typically encoded in PEM (Privacy Enhanced Mail) format. It is Base64-encoded text in the following format:
-----BEGIN CERTIFICATE REQUEST----- MIICvDCCAaQCAQAwdzELMAkGA1UEBhMCVVMxDTALBgNVBAgMBFV0YWgxDzANBgNV ... -----END CERTIFICATE REQUEST-----
By verifying that Common Name and organization information are correct before submitting the CSR to the CA, you can reduce certificate reissuance costs.
Verify that the required key length (e.g., RSA 2048-bit or higher) or algorithm (ECDSA recommended) specified in your organization's security policy is being used.
When certificate installation errors or browser warnings occur, quickly identify the cause by checking the CSR contents.
For wildcard or multi-domain certificates, verify that Subject Alternative Names (SANs) are correctly included.
No need to memorize OpenSSL commands; easily check CSR contents in your browser.
CSR data is processed in the browser and not sent to servers, allowing safe verification of sensitive information.
While CSRs contain only public keys, never expose private keys externally. If a private key is compromised, the SSL certificate becomes invalidated and communication can be intercepted.
Current standards require RSA 2048-bit or higher, or ECDSA (Elliptic Curve Cryptography). RSA 1024-bit is deprecated.
It is recommended to generate a new CSR and private key for each certificate renewal. Continuing to use old private keys increases the risk of compromise.
The Common Name (CN) must exactly match the domain name where the certificate will be used. For example, www.example.com and example.com are treated as different domains.
Wildcard certificates (*.example.com) are valid for subdomains (sub.example.com) but NOT for the main domain (example.com).
A CSR is like an 'application form' sent to the CA to obtain a certificate. The CA verifies the CSR content, digitally signs it, and issues the SSL certificate. The CSR contains the public key, while the SSL certificate contains both the public key and the CA's signature.
No, private keys are NOT included in CSRs. CSRs contain only public keys. This tool only parses CSR content and cannot access private keys.
Yes, if you generated a CSR with incorrect information (Common Name, organization name, etc.), you need to regenerate it with correct information. Issuing a certificate with an incorrect CSR may result in additional reissuance fees.
Specify the Common Name with an asterisk (*), like '*.example.com'. This will issue a certificate valid for all subdomains like sub.example.com, www.example.com, etc.
CSRs themselves do not have expiration dates, but from a security perspective, it is recommended to use them immediately after generation. CSRs left unused for long periods increase the risk of private key compromise, so regeneration is recommended.
SANs are an extension feature to cover multiple domain names with a single SSL certificate. For example, one certificate can cover www.example.com, example.com, and mail.example.com.
No, this tool is for verifying and checking CSR contents. To generate CSRs, use OpenSSL or server management panels.
ECDSA (Elliptic Curve Cryptography) provides equivalent security with shorter key lengths than RSA. For example, ECDSA 256-bit equals RSA 3072-bit. However, older browsers and systems may not support it, so if compatibility is important, choose RSA 2048-bit or higher.