2

I have a ssl cert and ssl key, is it possible to checkout its expiration time?

eg. ssl key:

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

ssl cert(omit)

because I sometimes in macos keychain know site's certificate have due time. if I just know the ssl key and ssl cert data, whether I can get the due time?

1
  • 2
    I hope this key isn't used for anything important. – stark Jun 12 at 10:51
5

Keys do not expire. Certificates do. Certificates are binary data. They are not human-readable without tools.

Depending on how the certificate as encoded, you can just rename it to .cer and open it on Windows. It’ll then show you all data that’s in the certificate.

With OpenSSL, you can inspect certificates on the command line:

openssl x509 -text -noout -in cert.pem

OpenSSL is available for basically everything, but you may have to install it first.

You’ll get something like this:

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            04:11:24:0f:88:1e:34:22:06:94:05:d0:74:e5:be:96:00:ec
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=US, O=Let's Encrypt, CN=R3
        Validity
            Not Before: May 16 13:25:30 2021 GMT
            Not After : Aug 14 13:25:30 2021 GMT
        Subject: CN=*.stackexchange.com
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:b6:91:0f:2e:ad:e9:c1:d3:44:32:5a:a3:2d:f7:
                    ca:2f:25:6e:6b:e0:ca:39:d9:63:36:1e:b7:d1:21:
                    ae:cb:43:12:aa:11:80:dc:3b:30:a9:7b:02:ed:66:
                    c5:42:ea:b3:9b:61:5d:17:2f:4f:36:d4:fd:7e:df:
                    ae:da:97:7d:23:e0:e0:f4:be:19:83:9e:a3:1b:2b:
                    32:a3:11:74:40:6c:dd:e3:ef:20:ee:2d:dc:0f:c2:
                    49:ce:89:fe:b2:fb:5f:c4:66:55:b5:4e:8b:23:2a:
                    79:33:2b:e7:94:7f:5d:2a:d8:ea:45:11:35:63:e5:
                    b6:69:b6:6d:b4:05:50:f8:15:76:36:6c:97:c6:d8:
                    61:6d:91:18:8a:69:a0:7a:71:aa:4c:d6:fb:b0:d9:
                    58:8f:f2:f9:e1:c9:9d:54:3d:82:60:81:b2:59:c5:
                    6a:c7:ff:69:c0:f4:31:08:a1:61:da:62:35:82:d5:
                    63:7a:af:4b:66:9e:73:23:63:e8:de:30:74:c4:ed:
                    e0:31:5f:66:70:66:27:fe:8e:a3:4f:c3:98:66:fc:
                    af:2c:0a:7d:f6:ce:e9:26:48:be:e7:12:7b:09:56:
                    7a:9a:f8:bc:9f:6d:5e:c1:56:a9:1b:70:cd:01:71:
                    87:a4:49:d1:3c:5b:31:bd:9d:77:4c:fe:7f:03:2d:
                    44:b9
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Key Usage: critical
                Digital Signature, Key Encipherment
            X509v3 Extended Key Usage: 
                TLS Web Server Authentication, TLS Web Client Authentication
            X509v3 Basic Constraints: critical
                CA:FALSE
            X509v3 Subject Key Identifier: 
                9C:66:DB:15:43:B5:06:86:B1:00:76:AC:9E:8F:5E:C0:3C:29:87:E8
            X509v3 Authority Key Identifier: 
                keyid:14:2E:B3:17:B7:58:56:CB:AE:50:09:40:E6:1F:AF:9D:8B:14:C2:C6

            Authority Information Access: 
                OCSP - URI:http://r3.o.lencr.org
                CA Issuers - URI:http://r3.i.lencr.org/

            X509v3 Subject Alternative Name: 
                DNS:*.askubuntu.com, DNS:*.blogoverflow.com, DNS:*.mathoverflow.net, DNS:*.meta.stackexchange.com, DNS:*.meta.stackoverflow.com, DNS:*.serverfault.com, DNS:*.sstatic.net, DNS:*.stackexchange.com, DNS:*.stackoverflow.com, DNS:*.stackoverflow.email, DNS:*.superuser.com, DNS:askubuntu.com, DNS:blogoverflow.com, DNS:mathoverflow.net, DNS:openid.stackauth.com, DNS:serverfault.com, DNS:sstatic.net, DNS:stackapps.com, DNS:stackauth.com, DNS:stackexchange.com, DNS:stackoverflow.blog, DNS:stackoverflow.com, DNS:stackoverflow.email, DNS:stacksnippets.net, DNS:superuser.com
            X509v3 Certificate Policies: 
                Policy: 2.23.140.1.2.1
                Policy: 1.3.6.1.4.1.44947.1.1.1
                  CPS: http://cps.letsencrypt.org

            1.3.6.1.4.1.11129.2.4.2: 
                ......v.D.e......@....(.......1.?.3........yu.Y5.....G0E.!....Q...g^Mrv..."gK
..Y|.q.....|.. d?...#...<...k..V.]J.._.&........v.}>.....Uh$....R.y+..x...j.h.~".....yu.Y].....G0E. ~<H..../Z1..%k.;.Q$$3....m...q)..!....w...O.!............J.C.He...L
    Signature Algorithm: sha256WithRSAEncryption
         18:05:01:11:f4:4e:e7:51:c4:5e:91:9e:3f:ec:bd:8b:32:85:
         5d:74:08:f7:98:15:74:7b:9f:80:49:79:64:a8:ea:7b:0a:0c:
         25:ed:08:d0:09:23:e2:48:55:ca:10:4e:d6:d9:d4:34:c3:85:
         9b:2b:d0:c4:22:b0:d4:66:bf:49:3a:6d:7e:78:b3:e6:56:c3:
         18:83:f4:31:0e:62:3f:34:a6:9d:c4:82:cd:45:13:60:2d:ca:
         9e:7f:5c:63:f7:e4:49:8d:1b:a2:75:cd:72:97:fb:2a:c0:c7:
         62:76:46:93:5f:8c:84:a4:42:99:50:f6:ef:aa:a6:f7:ab:41:
         91:5c:7a:9e:b6:59:4b:e5:b2:da:47:7e:30:30:56:6d:84:0c:
         aa:7e:14:80:6f:31:4e:6f:fa:84:d4:42:0c:ab:b8:8c:c6:77:
         b1:96:e8:a1:e2:ba:e3:57:e1:f8:b4:b9:40:52:e1:da:62:4c:
         d3:0c:7e:41:05:75:a6:ab:9b:71:54:07:36:93:83:f8:f3:38:
         ba:b3:41:eb:32:64:39:74:62:6a:d0:18:6d:f7:72:5a:3a:d5:
         08:e9:29:b0:e3:44:95:ac:2e:d7:29:b6:7a:3c:df:ad:08:55:
         1a:e3:ce:c7:57:fe:8f:1f:66:25:ba:59:73:83:e1:53:ac:38:
         a2:4d:36:39

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