CRT File Documentation


Feature Value
File Extension .crt
Format Type Binary
Full Name Certificate File
MIME Type application/x-x509-ca-cert
Standard X.509
Used For SSL/TLS Certificates
Encryption Possible, using RSA, DSA, ECC
Key Sizes 2048-bit commonly, 3072 and 4096 for higher security
Issuer Details about the certificate authority (CA) issuing the certificate
Subject Details about the entity the certificate represents
Validity Period Specified start and end dates between which the certificate is valid
Public Key Algorithm RSA, DSA, ECDSA, etc.
Signature Algorithm SHA-256 with RSA Encryption, among others
Version X.509 v1, v2, or v3
Serial Number Unique identifier for the certificate
Thumbprint (SHA-1) A SHA-1 hash of the certificate
Extension Support Support for extensions in v3 for additional attributes
Revocation Information Details on how to check if the certificate is revoked
Usage Client Authentication, Server Authentication, etc.
Application Web servers, Email encryption, Code signing