Computing/SSL

Using wget to download files from certificate-protected sites at MIT:

• Download MIT CA
• Convert the extracted MIT CA from DER to PEM format:

openssl x509 -out mitca.pem -outform pem -in mitca.crt -inform der 

• Install personal MIT certificate into web browser
• Extract private and public keys from the .p12 certificate (converting from pkcs12 to PEM). The first step extracts the private key and the second one extracts the public key:

openssl pkcs12 -nocerts -in usercert.p12 -out ~user/userkey.pem
chmod 400 ~user/userkey.pem
openssl pkcs12 -clcerts -nokeys -in usercert.p12 -out ~user/usercert.pem

• Use the certificates to download files:

wget --private-key=/home/user/mitkey.pem \
--certificate=/home/user/mitcert.pem \
--ca-certificate=/home/user/mitca.pem \
https://web.mit.edu/rhlinux/rhel-5.0/5.0-client-i386/rhel-5-client-i386-disc4.iso

Notes

You won't need the --ca-certificate flag if the server SSL cert is signed up a CA recognized in the wget default CA bundle. Now, more importantly, if you remove the --certificate and --private-key parts, that wget should FAIL, giving you an error something like this: OpenSSL: error:14094410:SSL routines:SSL3_READ_BYTES:sslv3 alert

References

• Certificate manipulation
• https://biowiki.mit.edu/wiki/index.php/Setting_Up_SSL_on_Web_Servers
• http://web.mit.edu/apache-ssl/
• http://mark.foster.cc/kb/openssl-keytool.html
• http://mark.foster.cc/kb/cacert-keystore-extraction.html
• http://www.ender.com/2005/11/installing_your_own_ca_authori.html
• From the openssl man page:

      --certificate=file
          Use the client certificate stored in file.  This is needed for
          servers that are configured to require certificates from the
          clients that connect to them.  Normally a certificate is not
          required and this switch is optional.
      --private-key=file
          Read the private key from file.  This allows you to provide the
          private key in a file separate from the certificate.
      --ca-certificate=file
          Use file as the file with the bundle of certificate authorities
          (‘‘CA’’) to verify the peers.  The certificates must be in PEM format.
      --no-check-certificate
          Don’t check the server certificate against the available certificate authorities.