The secretive, highly contentious security certificate process strikes a balance between upholding fundamental human rights and protecting society from security threats, says a former top official with the Canadian Security Intelligence Service.

In an exclusive interview with host Evan Solomon on CBC News Network's Power and Politics, Ray Boisvert, former assistant director of intelligence for CSIS, said intense scrutiny and various legal challenges have fine-tuned the rarely used process.

First established in 1978, security certificates have been used in fewer than 30 cases since 1991, according to Boisvert, who is now president of I-Sec Integrated Strategies. The threat environment has "transformed tremendously" and requires a delicate balance between enabling the state to protect its citizens as a fundamental obligation – and upholding individual freedoms protected under the Canadian Charter of Rights and Freedoms, he added.

Boisvert said intelligence gathered by spy agencies is not meant to be used in court like evidence gathered by law enforcement agencies, and is usually obtained and shared through a network of international partners. In the case of security certificates, the information is used in a quasi-judicial setting, creating a "clash" because it can be challenged by lawyers and judges, Boisvert said.

'Significant amount of accountability'

But courts have been "very, very successful" in pulling cases apart — questioning sources and the validity of collection methods. Special advocates and the requirement for ministerial sign-off have added to the accountability despite a lack of transparency and non-disclosure to the accused, he said.

"I think that in itself has proved that despite some of the rhetoric, there is a significant amount of accountability, and those individuals involved in the collection of that information and the presentation of those cases to Federal Court are doing so in a very professional and a very meticulous manner," Boisvert said on Power & Politics.

Boisvert, who has been involved in many security certificate cases during his time at CSIS, could not speak on any specific one – including that of Mohamed Mahjoub.

Today, former Public Safety minister Stockwell Day testified via video link before a federal court in Toronto about his role in issuing that security certificate. He said there were warnings some of the information used to detain Mahjoub may have come from the torture of the Egyptian-born man.

Mahjoub, 51, has been imprisoned and under house arrest since 2000 without facing any charges. Day said material pointed to Majhoub's involvement in 'Vanguard of Conquest,' a group tied to late al-Qaeda leader Osama Bin Laden.

Julie Carmichael, spokeswoman for current Public Safety Minister Vic Toews, could not comment on the specific case, but defended the security certificate process.

"The security certificates process allows the government to take action against individuals believed to be inadmissible to Canada on very serious grounds, including terrorism," she told Power and Politics. "Our objective is to ensure Canadians are safe from terrorist threats."

According to Public Safety Canada's website, the security certificate process falls within the Immigration and Refugee Protection Act and is not a criminal proceeding, but an immigration proceeding. The objective is to remove non-Canadians "who have no legal right to be here and who pose a serious threat to Canada and Canadians."

The site says the government issues a certificate only in "exceptional circumstances" where the information to determine the case cannot be disclosed without endangering the safety of any person or national security. Individuals subject to a certificate have been deemed inadmissible on grounds of national security, violating human or international rights, or involvement in organized or serious crimes, according to the department.