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Solution ID : SO18140

Last Modified : 05/02/2018

What extensions and details are included in a SSL certificate?

Cause

 

 

Solution

The following fields are attributes that may be included in the SSL certificate details.
Note: with changing PKI standards, these attributes may change at any time without notice to comply with CAB Forum requirements. 

Version
Serial Number
Signature Algorithm
Issuer
Valid From and Valid To
Subject
Public Key
Subject Alternative Name (SAN)
Basic Constraints
Subject Key Identifier (SKI)
Key Usage
CRL Distribution Points
Certificate Policies
Extended Key Usage (EKU)
Authority Key Identifier (AKI)
Authority Info Access
Logotype
Thumbprint Algorithm
Thumbprint

  • Version:
    This field describes the version of the encoded certificate.  For SSL certificates, the X.509 version is 3 since certificate extensions are used.


     
  • Serial Number:
    The Serial Number is a positive integer assigned by Symantec to each SSL certificate.  It is unique for each certificate issued by Symantec (i.e., the issuer name and serial number identify a unique certificate).


     
  • Signature Algorithm:
    The Signature Algorithm identifies the cryptographic algorithm used by Symantec to sign this certificate.  As of 2016, Symantec signs all SSL certificates using the SHA-2 Algorithm.


     
  • Issuer:
    The Issuer field identifies the entity who has signed and issued the certificate.  For SSL certificates, this would contain the the Distinguished Name (DN) information for the Intermediate CA Certificate.

     

     
  • Valid From and Valid To:
    These fields indicate the validity period of the SSL certificate.



     
  • Subject:
    This contains the Distinguished Name (DN) information for the certificate.  The fields included in a typical SSL certificate are:

    Common Name (CN)
    Organization (O)
    Organizational Unit (OU)
    Locality or City (L)
    State or Province (S)
    Country Name (C)


    For Extended Validation (EV) SSL certificates, these additional fields are also included:

    Company Street Address
    Postal Code
    Business Category
    Serial Number (Business Registration Number)
    Jurisdiction State
    Jurisdiction Locality



     
  • Public Key:
    This field is used to identify the algorithm with which the SSL certificate is used.  It also contains the byte-array information for the certificate.



     
  • Subject Alternative Name (SAN):
    The Subject Alternative Name extension allows additional identities to be bound to the subject of the certificate. The DNS name (dNSName) extension is used to add an additional fully qualified domain name to a SSL certificate.


     
  • Basic Constraints:
    This extension indicates whether a certificate is a Certificate Authority (CA) or not.  If the certificate is a CA, then additional information, such as the depth of the hierarchy it can sign, is specified. SSL certificates are end-entity certificates, not CA certificates.



  • Subject Key Identifier (SKI):
    The Subject Key Identifier extension provides a means of identifying certificates that contain a particular public key.  This is a hash value of the SSL certificate.
     


     

  • Key Usage:
    The Key Usage extensions define what a particular certificate may be used for (assuming the application can parse this extension).  The following extensions are included in an SSL certificate:

    Digital Signature: (Taken from http://www.ietf.org/rfc/rfc3280.txt) The digitalSignature bit is asserted when the subject public key is used with a digital signature mechanism to support security services other than certificate signing (bit 5), or CRL signing (bit 6). Digital signature mechanisms are often used for entity authentication and data origin authentication with integrity.

    Key Encipherment: (Taken from http://www.ietf.org/rfc/rfc3280.txt) The keyEncipherment bit is asserted when the subject public key is used for key transport. An example of Key Encipherment is the SSL handshake, where the two applications use asymmetric encryption to wrap around the exchange of a secret key that is ultimately used for the session.

  • CRL Distribution Points:
    The CRL Distribution Points extension provides the location of the corresponding Certificate Revocation List (CRL) for the SSL certificate.

  • Certificate Policies:
    The Certificate Policies extension defines the legal rules associated with a particular certificate’s usage.  For Symantec SSL certificates, a link to the Symantec Relying Party Agreements is provided: https://www.symantec.com/about/legal/repository.jsp#rpa-ts

  • Extended Key Usage (EKU):
    This extension indicates one or more purposes for which the certified public key may be used, in addition to or in place of the basic purposes already indicated in the key usage extension.  Symantec SSL Certificates include the following extensions:

    Server Authentication: (Taken from http://www.ietf.org/rfc/rfc3280.txt) TLS WWW server authentication. Key usage bits that may be consistent: digitalSignature, keyEncipherment or keyAgreement

    Client Authentication: (Taken from http://www.ietf.org/rfc/rfc3280.txt) TLS WWW client authentication. Key usage bits that may be consistent: digitalSignature and/or keyAgreement

    Symantec Secure Site Pro  (Premium) SSL certificates also have the following extension: 2.16.840.1.113730.4.1 - Netscape Server Gated Crypto (nsSGC)

  • Authority Key Identifier (AKI):
    The Authority Key Identifier extension provides the key identifier of the Issuing CA certificate that signed the SSL certificate.  This AKI value would match the SKI value of the Intermediate CA certificate.

  • Authority Info Access:
    The Authority Info Access extension provides information about how to access information about a CA, such as OCSP validation and CA policy data.


     

  • Logotype:
    The Logotype extension is a logotype representing the organization identified as part of the issuer name in the certificate.


     

  • Thumbprint Algorithm:
    This extension indicates the algorithm used to hash the certificate.


     

  • Thumbprint:
    This extension provides the actual hash to ensure that the certificate has not been tampered with.

 This information has been taken from RFC 3280: http://www.ietf.org/rfc/rfc3280.txt