Ssl – Converting .cer to .pem

sslssl-certificate

I have zero knowledge on certificates . I searched on internet and found few , but none of them helped me in my case.

I am on Red Hat Enterprise Linux ES release 4 (Nahant Update 9)

I am trying to convert .cer ( this is a CAS certificate) to .pem and getting the below error

openssl x509 -inform der -in cas.cer -out cas.pem
unable to load certificate
4419:error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag:tasn_dec.c:959:
4419:error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error:tasn_dec.c:304:Type=X509

I am able to read the plain text of it just by running

[root@sls32 install]# openssl x509 -in cas.cer -text -noout
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 1331657215 (0x4f5f79ff)
        Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=USA, ST=PA, L=KOP, O=TEST, OU=TEST, CN=TEST.com
        Validity
            Not Before: Mar 13 16:46:55 2012 GMT
            Not After : Dec 27 16:46:55 2016 GMT
        Subject: C=USA, ST=PA, L=Malvern, O=TEST, OU=TEST, CN=TEST.co                                                                                                             m
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
            RSA Public Key: (1024 bit)
                Modulus (1024 bit):
                    00:9d:af:d0:c9:ce:8f:50:88:72:46:34:d3:b3:80:
                    e2:07:61:21:10:1f:b2:81:ce:7f:ad:0b:d3:5c:d3:
                    67:33:b1:20:e7:fc:8b:aa:5e:5a:e5:22:1e:91:c3:
                    e9:29:7e:d0:ea:ec:32:35:b1:b9:b6:d7:ca:e7:7a:
                    21:c3:91:99:fa:14:61:b5:20:31:40:28:cb:93:07:
                    04:dd:dc:56:f0:1e:ac:dd:11:8a:86:db:27:66:e7:
                    31:3f:81:50:17:8c:3d:3a:c5:92:ed:f8:52:e7:cc:
                    44:66:1d:9f:96:a4:1b:9b:ad:13:6a:e3:9c:dc:b8:
                    fb:81:28:76:cd:f7:a5:9d:f7
                Exponent: 65537 (0x10001)
    Signature Algorithm: sha1WithRSAEncryption
        28:68:a0:0b:f1:cc:20:b2:d9:69:a5:1b:4b:fc:83:ad:f8:4d:
        2a:cf:2e:7f:10:7c:60:d0:9b:63:2c:54:be:df:15:32:c7:56:
        b8:56:45:a8:62:af:77:25:b7:17:b0:ef:3f:b9:41:d0:17:90:
        8c:b9:a3:8b:bd:d2:72:89:4f:85:d5:96:c4:7b:9a:e5:ec:89:
        3d:16:c5:9c:70:91:13:79:8b:ef:1d:d0:88:eb:e4:23:e2:6c:
        79:68:bf:69:30:c9:9c:98:d8:1e:a5:b8:b6:ed:07:32:88:c6:
        6e:f2:69:d2:f9:06:22:7a:9a:cd:92:1e:3b:b1:4c:7b:14:4a:
        69:48

Could any body give me the correct command for it ?

Thank You

Best Answer

Actually, the .cer and .pem extensions are quite confusing for me. From the command output provided, I think your cas.cer should be bas64 encoded, which is the format accepted by OpenSSL without any additional parameter.

So, you may try to copy the cas.cer to cas.pem (no conversion is needed, just change the filename).

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