89/100 SECURITY SCORE

Certificate Information

Subject
CN=blog.martincheng0.com
Issuer
C=US, O=Let's Encrypt, CN=R13
Valid From
October 28, 2025
Valid Until
January 26, 2026 71 days
Public Key
RSA 2048 bit Adequate
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
80:2D:2A:02:89:71:E8:98:59:EF:B7:64:7C:E4:AA:99:D4:58:37:07:14:A6:A3:60:D1:CE:FE:28:8F:D4:A1:4F
Alternative Names

Security Configuration

TLS Protocols
TLS 1.2 TLS 1.3
Forward Secrecy
Supported (Modern clients use PFS)

HTTP Security Headers

Status
Strict-Transport-Security
Present
max-age=63072000
Content-Security-Policy
Basic
default-src; script-src; style-src; +2 more
X-Frame-Options
Excellent
deny
X-Content-Type-Options
Good
nosniff
Referrer-Policy
Present
origin-when-cross-origin
Permissions-Policy
Missing
Not configured
Recommendations
  • Increase HSTS max-age to at least 1 year and add includeSubDomains
  • Improve CSP by adding more specific directives and removing 'unsafe-inline'
  • Consider adding Permissions-Policy to control browser features

CAA Records (Certificate Authority Authorization)

CAA Records
Not Configured (Any CA can issue certificates)
CAA Issues
  • No CAA records configured - any CA can issue certificates
Recommendations
  • Implement CAA records to restrict which CAs can issue certificates for your domain
  • This adds an extra layer of security against unauthorized certificate issuance
  • Example: Add CAA record 'example.com. CAA 0 issue "letsencrypt.org"'
  • Consider adding 'iodef' record to receive security incident reports

Subject Alternative Names

1 domain