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SECURITY SCORE
Certificate Information
Subject
CN=gitbook.io
Issuer
C=US, O=Google Trust Services, CN=WE1
Valid From
January 21, 2026
Valid Until
April 21, 2026
80 days
Public Key
ECDSA
256 bit
(P-256)
Adequate
Signature Algorithm
ECDSA-SHA256
SHA-256 Fingerprint
A4:38:A4:E0:73:26:0F:CC:8E:F4:46:3D:B2:27:80:0D:90:EA:B4:4B:FA:4F:61:2E:A3:6A:7C:2F:F6:90:88:1B
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
Missing
Not configured
Content-Security-Policy
Missing
Not configured
X-Frame-Options
Missing
Not configured
X-Content-Type-Options
Missing
Not configured
Referrer-Policy
Missing
Not configured
Permissions-Policy
Missing
Not configured
Recommendations
- • Add Strict-Transport-Security header with max-age of at least 1 year
- • Add Content-Security-Policy header to prevent XSS attacks
- • Add X-Frame-Options: DENY or SAMEORIGIN to prevent clickjacking
- • Add X-Content-Type-Options: nosniff
- • Add Referrer-Policy header (recommended: strict-origin-when-cross-origin)
- • Consider adding Permissions-Policy to control browser features
CAA Records (Certificate Authority Authorization)
CAA Records
Configured
(Restricts certificate issuance)
Current Issuer
Authorized
(Matches CAA policy)
Authorized CAs
Recommendations
- • Consider using critical flag (flags=128) for stricter CAA enforcement
- • Consider adding 'iodef' records to receive notifications about unauthorized certificate issuance attempts
- • Consider adding 'issuewild' records to control wildcard certificate issuance