Sebelius countered that the system is secure, even though the site's certificate, known in government parlance as an "authority to operate," is of a temporary nature. A permanent certificate will be issued only when all security issues are addressed, she stressed.
Spokeswoman Joanne Peters added separately: "When consumers fill out their online ... applications, they can trust that the information they're providing is protected by stringent security standards and that the technology underlying the application process has been tested and is secure. Security testing happens on an ongoing basis using industry best practices."
The security certificate is required under longstanding federal policy before any government computer system can process, store or transmit agency data. The temporary certificate was approved by Medicare chief Marilyn Tavenner, the senior HHS official closest to the rollout. No major security breaches have been reported.
The memo said, "From a security perspective, the aspects of the system that were not tested due to the ongoing development, exposed a level of uncertainty that can be deemed as a high risk for the (federal marketplace website)."
It recommended setting up a security team to address risks and conduct daily tests, and said a full security test should be conducted within two to three months of the website going live.
A separate page stated that "the mitigation plan does not reduce the risk to the (website) itself going into operation on October 1, 2013. However, the added protections do reduce the risk to the overall Marketplace operations and will ensure that the ... system is completely tested within the next 6 months."
That page was signed by three senior technical officials below Tavenner at the Centers for Medicare and Medicaid Services. All the officials deal with information security issues.
Republicans opposed to Obama's health care law are calling for Sebelius to resign. She apologized to people having trouble signing up but told the committee that the technical issues that led to frozen screens and error messages are being cleared up on a daily basis.