Verifying A Certificate - ZyXEL Communications ZyWall ATP series User Manual

Certificate File Formats
Any certificate that you want to import has to be in one of these file formats:
• Binary X.509: This is an ITU-T recommendation that defines the formats for X.509 certificates.
• PEM (Base-64) encoded X.509: This Privacy Enhanced Mail format uses lowercase letters, uppercase
letters and numerals to convert a binary X.509 certificate into a printable form.
• Binary PKCS#7: This is a standard that defines the general syntax for data (including digital signatures)
that may be encrypted. A PKCS #7 file is used to transfer a public key certificate. The private key is not
included. The Zyxel Device currently allows the importation of a PKS#7 file that contains a single
certificate.
• PEM (Base-64) encoded PKCS#7: This Privacy Enhanced Mail (PEM) format uses lowercase letters,
uppercase letters and numerals to convert a binary PKCS#7 certificate into a printable form.
• Binary PKCS#12: This is a format for transferring public key and private key certificates. The private key
in a PKCS #12 file is within a password-encrypted envelope. The file's password is not connected to
your certificate's public or private passwords. Exporting a PKCS #12 file creates this and you must
provide it to decrypt the contents when you import the file into the Zyxel Device.
Note: Be careful not to convert a binary file to text during the transfer process. It is easy for this
to occur since many programs use text files by default.

34.11.2 Verifying a Certificate

Before you import a trusted certificate into the Zyxel Device, you should verify that you have the correct
certificate. You can do this using the certificate's fingerprint. A certificate's fingerprint is a message
digest calculated using the MD5 or SHA1 algorithm. The following procedure describes how to check a
certificate's fingerprint to verify that you have the actual certificate.
Browse to where you have the certificate saved on your computer.
1
Make sure that the certificate has a ".cer" or ".crt" file name extension.
2
Figure 430 Remote Host Certificates
Double-click the certificate's icon to open the Certificate window. Click the Details tab and scroll down
3
to the Thumbprint Algorithm and Thumbprint fields.
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