Linux Security Cookbook

4.5. Decoding an SSL Certificate

Problem

You want to view information about a given SSL certificate, stored in a PEM file.

Solution

$ openssl x509 -text -in filename
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            d0:1e:40:90:00:00:27:4b:00:00:00:01:00:00:00:04
        Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=US, ST=Utah, L=Salt Lake City, O=Xcert EZ by DST, CN=Xcert EZ by 
DST/Email=[e-mail]
        Validity
            Not Before: Jul 14 16:14:18 1999 GMT
            Not After : Jul 11 16:14:18 2009 GMT
        Subject: C=US, ST=Utah, L=Salt Lake City, O=Xcert EZ by DST, CN=Xcert EZ by 
DST/Email=[e-mail]
...

Discussion

This is a quick way to learn who issued a certificate, its begin and end dates, and other pertinent details.

See Also

openssl(1).