Para mostrar el contenido de un certificado, usamos como ejemplo un certificado propio ya caducado.

Este es el certificado completo:

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 0 (0x0)
        Signature Algorithm: md5WithRSAEncryption
        Issuer: C=ES, ST=Castellon, L=Castellon, O=None, OU=None, CN=Pablo Romeu/Email=promeu@ono.com
        Validity
            Not Before: Dec 21 10:49:15 2001 GMT
            Not After : Jan 20 10:49:15 2002 GMT
        Subject: C=ES, ST=Castellon, L=Castellon, O=None, OU=None, CN=Pablo Romeu/Email=promeu@ono.com
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
            RSA Public Key: (1024 bit)
                Modulus (1024 bit):
                    00:be:3c:cd:3a:5d:d3:cd:08:48:43:c2:92:0a:01:
                    04:72:f7:c0:b9:9a:81:5d:43:50:8e:9a:ed:f6:34:
                    b6:bb:1c:df:cc:a2:7c:18:e4:04:e1:bc:f4:2e:16:
                    92:8e:ff:23:09:fd:77:ad:11:54:79:3d:33:91:2f:
                    46:bc:8e:f4:50:85:c4:d8:32:19:45:8d:79:3b:b9:
                    ff:a1:7c:f0:3e:a9:f5:0b:fd:3f:c2:a9:59:db:bb:
                    5a:ce:6a:21:8a:b9:3e:a1:d3:19:02:90:6f:15:7b:
                    a1:2b:ff:b1:37:96:d8:1d:d8:61:fc:1f:d7:2a:36:
                    8d:58:e2:24:a3:3a:36:7d:25
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Subject Key Identifier: 
                3A:B6:B0:43:AF:DC:5A:DA:7E:AC:47:85:07:51:7B:EE:76:23:72:76
            X509v3 Authority Key Identifier: 
                keyid:3A:B6:B0:43:AF:DC:5A:DA:7E:AC:47:85:07:51:7B:EE:76:23:72:76
                DirName:/C=ES/ST=Castellon/L=Castellon/O=None/OU=None/CN=Pablo Romeu/Email=promeu@ono.com
                serial:00
            X509v3 Basic Constraints: 
                CA:TRUE
    Signature Algorithm: md5WithRSAEncryption
        9a:ea:ae:c8:d9:f0:b3:17:71:db:37:76:67:12:5c:d0:78:8c:
        b7:f1:52:db:71:7c:f8:a1:6a:7c:a2:6a:7d:d2:b5:af:4d:ce:
        0f:80:5f:7d:e1:a2:b4:23:33:fb:83:db:75:fa:7f:c2:cf:58:
        ad:07:91:ef:c5:10:8b:d5:dd:ff:7d:7c:5a:5e:99:af:fb:73:
        4e:81:ef:0b:89:d2:9e:ab:25:ad:16:3b:57:8e:68:ae:de:4f:
        a6:7b:c3:9a:74:46:7e:c4:ed:51:9a:ef:83:38:c9:d1:9e:00:
        ba:d0:2f:42:c7:f1:f3:0e:a5:35:c3:07:f9:af:7e:c8:78:f1:
        a0:33
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,2EE25840A0914515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-----END RSA PRIVATE KEY-----
Aquí vamos comentándolo
Certificate:	Inicio del certificado
    Data:	Datos del certificado
        Version: 3 (0x2)	Versión y número de serie
        Serial Number: 0 (0x0)
        Signature Algorithm: md5WithRSAEncryption	Algoritmo con el que está firmado
	El siguiente campo se conoce como Distinguisher Name (o DN) del Issuer. Este campo contiene 
	los datos de la CA que emite el certificado. En este caso, es un certificado autofirmado, 
	pues el titular y la CA son la misma persona. En este campo se incluye la nacionalidad 
	(espresada con las dos letras del estándar ISO), Dirección, Organización, Departamento
	Common Name (nombre o seudónimo) y algún otro dato que pueda ser de interés (en este caso
	el email)
	
        Issuer: C=ES, ST=Castellon, L=Castellon, O=None, OU=None, CN=Pablo Romeu/Email=promeu@ono.com
	Periodo de validez del certificado.	
        Validity
            Not Before: Dec 21 10:49:15 2001 GMT
            Not After : Jan 20 10:49:15 2002 GMT
	Este es el DN del titular del certificado
        Subject: C=ES, ST=Castellon, L=Castellon, O=None, OU=None, CN=Pablo Romeu/Email=promeu@ono.com
	Información sobre la clave pública del certificado.
        Subject Public Key Info:
	Se usa el algoritmo RSA de 1024 bits
            Public Key Algorithm: rsaEncryption
            RSA Public Key: (1024 bit)
	Módulo de la clave pública	
                Modulus (1024 bit):
                    00:be:3c:cd:3a:5d:d3:cd:08:48:43:c2:92:0a:01:
                    04:72:f7:c0:b9:9a:81:5d:43:50:8e:9a:ed:f6:34:
                    b6:bb:1c:df:cc:a2:7c:18:e4:04:e1:bc:f4:2e:16:
                    92:8e:ff:23:09:fd:77:ad:11:54:79:3d:33:91:2f:
                    46:bc:8e:f4:50:85:c4:d8:32:19:45:8d:79:3b:b9:
                    ff:a1:7c:f0:3e:a9:f5:0b:fd:3f:c2:a9:59:db:bb:
                    5a:ce:6a:21:8a:b9:3e:a1:d3:19:02:90:6f:15:7b:
                    a1:2b:ff:b1:37:96:d8:1d:d8:61:fc:1f:d7:2a:36:
                    8d:58:e2:24:a3:3a:36:7d:25
	Exponente 
                Exponent: 65537 (0x10001)
	Extensiones del estándar x509 v.3
        X509v3 extensions:
            X509v3 Subject Key Identifier: 
                3A:B6:B0:43:AF:DC:5A:DA:7E:AC:47:85:07:51:7B:EE:76:23:72:76
            X509v3 Authority Key Identifier: 
                keyid:3A:B6:B0:43:AF:DC:5A:DA:7E:AC:47:85:07:51:7B:EE:76:23:72:76
                DirName:/C=ES/ST=Castellon/L=Castellon/O=None/OU=None/CN=Pablo Romeu/Email=promeu@ono.com
                serial:00
            X509v3 Basic Constraints: 
                CA:TRUE
	Firma de la CA
    Signature Algorithm: md5WithRSAEncryption
        9a:ea:ae:c8:d9:f0:b3:17:71:db:37:76:67:12:5c:d0:78:8c:
        b7:f1:52:db:71:7c:f8:a1:6a:7c:a2:6a:7d:d2:b5:af:4d:ce:
        0f:80:5f:7d:e1:a2:b4:23:33:fb:83:db:75:fa:7f:c2:cf:58:
        ad:07:91:ef:c5:10:8b:d5:dd:ff:7d:7c:5a:5e:99:af:fb:73:
        4e:81:ef:0b:89:d2:9e:ab:25:ad:16:3b:57:8e:68:ae:de:4f:
        a6:7b:c3:9a:74:46:7e:c4:ed:51:9a:ef:83:38:c9:d1:9e:00:
        ba:d0:2f:42:c7:f1:f3:0e:a5:35:c3:07:f9:af:7e:c8:78:f1:
        a0:33
	Esta es una copia del certificado codificado mediante triple DES
-----BEGIN CERTIFICATE-----
MIIDcTCCAtqgAwIBAgIBADANBgkqhkiG9w0BAQQFADCBiDELMAkGA1UEBhMCRVMx
EjAQBgNVBAgTCUNhc3RlbGxvbjESMBAGA1UEBxMJQ2FzdGVsbG9uMQ0wCwYDVQQK
EwROb25lMQ0wCwYDVQQLEwROb25lMRQwEgYDVQQDEwtQYWJsbyBSb21ldTEdMBsG
CSqGSIb3DQEJARYOcHJvbWV1QG9uby5jb20wHhcNMDExMjIxMTA0OTE1WhcNMDIw
MTIwMTA0OTE1WjCBiDELMAkGA1UEBhMCRVMxEjAQBgNVBAgTCUNhc3RlbGxvbjES
MBAGA1UEBxMJQ2FzdGVsbG9uMQ0wCwYDVQQKEwROb25lMQ0wCwYDVQQLEwROb25l
MRQwEgYDVQQDEwtQYWJsbyBSb21ldTEdMBsGCSqGSIb3DQEJARYOcHJvbWV1QG9u
by5jb20wgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAL48zTpd080ISEPCkgoB
BHL3wLmagV1DUI6a7fY0trsc38yifBjkBOG89C4Wko7/Iwn9d60RVHk9M5EvRryO
9FCFxNgyGUWNeTu5/6F88D6p9Qv9P8KpWdu7Ws5qIYq5PqHTGQKQbxV7oSv/sTeW
2B3YYfwf1yo2jVjiJKM6Nn0lAgMBAAGjgegwgeUwHQYDVR0OBBYEFDq2sEOv3Fra
fqxHhQdRe+52I3J2MIG1BgNVHSMEga0wgaqAFDq2sEOv3FrafqxHhQdRe+52I3J2
oYGOpIGLMIGIMQswCQYDVQQGEwJFUzESMBAGA1UECBMJQ2FzdGVsbG9uMRIwEAYD
VQQHEwlDYXN0ZWxsb24xDTALBgNVBAoTBE5vbmUxDTALBgNVBAsTBE5vbmUxFDAS
BgNVBAMTC1BhYmxvIFJvbWV1MR0wGwYJKoZIhvcNAQkBFg5wcm9tZXVAb25vLmNv
bYIBADAMBgNVHRMEBTADAQH/MA0GCSqGSIb3DQEBBAUAA4GBAJrqrsjZ8LMXcds3
dmcSXNB4jLfxUttxfPihanyian3Sta9Nzg+AX33horQjM/uD23X6f8LPWK0Hke/F
EIvV3f99fFpema/7c06B7wuJ0p6rJa0WO1eOaK7eT6Z7w5p0Rn7E7VGa74M4ydGe
ALrQL0LH8fMOpTXDB/mvfsh48aAz
-----END CERTIFICATE-----
	Esta es la clave privada (Cifrada), que no se incluye en el certificado, 
	sino aparte, pues el certificado se envía habitualmente a otras
	personas para realizar transacciones seguras con ellas.
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,2EE25840A0914515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-----END RSA PRIVATE KEY-----