The National Academies' Web site runs on a mix of servers, with different levels of security throughout our site. Areas of our Web site that receive or contain confidential information are protected through "secure socket layer" (SSL) encryption.
SSL is the most widely accepted way of protecting data transmitted to and from public Web sites. One advantage to SSL-based security is the use of digital "certificates" to verify the identities of our Web servers, preventing outside servers from posing as secure areas of the National Academies' site.
Because both your Web browser and our Web servers must have compatible certificates for the SSL security to work, the digital certificates we use are issued by VeriSign, Inc. (TM) whose technology is integrated into many commercial Web browsers.
Certificates expire and must be updated periodically. The VeriSign certificate in certain older browser versions expired at the end of 1999. If your browser certificate has expired and you attempt to access secure areas of the National Academies site, you will see a warning message indicating that "the Verisign certificate is expired" and that transmissions may not be secure. If you see this message, it does not mean that there is a security problem. It means that your Web browser may no longer compatible with the current certificates.
To address this, VeriSign recommends upgrading older browsers to newer versions. For information on upgrading Netscape or Microsoft browsers, information is available on the following following websites:
If you use a different browser and need more information, please contact your Internet service provider or your organization's
If you use a different browser and need more information, please contact your Internet service provider or your organization's
computer support department.
Note that VeriSign and the VeriSign logo are trademarks and service marks or registered trademarks and service marks of VeriSign, Inc. For a more detailed explanation of the expired-certificate issue, you may visit the VeriSign website, on the Web at: