OTTAWA -- While controversy swirls around Hillary Clinton for deleting tens of thousands of emails in a personal account she used while serving as U.S. secretary of state, the Canadian government has based its own approach to officials' private text messages on the honour system.

Treasury Board guidelines give bureaucrats free rein to wipe any non-work-related instant messages from their government-issued mobile devices. They are supposed to hold on to texts or PINs that mention government business for record-keeping purposes.

But a newly released document shows the department grappled with an unforeseen technological hurdle that could have scuttled the whole plan.

"Some models of the new generation BlackBerry devices (e.g. Q10 or Passport) do not permit a user to forward PIN-to-PIN messages to email accounts, this making it difficult to retain such messages, or to capture them for response to an (access-to-information) request," says a note attached to a December 2014 memo for Treasury Board Secretary Yaprak Baltacioglu.

PINs, or personal identification numbers, are unique IDs that can be used to send secure messages to other BlackBerry users.

That limitation put Treasury Board -- which is responsible for coming up with information technology and access-to-information rules for all government departments -- in a bit of a bind.

BlackBerry came up with a few work-arounds. Bureaucrats could cut and paste their PIN messages -- including the "to," "from," "date," "time" and "subject" fields -- into an email, which they would then send to themselves.

They also had the option of taking screen shots of their PINs, or they could simply write out a copy of their message and store it away in an email message or a Word document.

Treasury Board suggested ditching PINs altogether.

"Please note that it is a recommended best practice to discontinue the use of PIN-to-PIN messaging and use BlackBerry Messenger (BBM) capability instead, as BBM messages can be easily forwarded to a government of Canada email address," says the note attached to Baltacioglu's memo.

The Canadian Press obtained the document under the Access to Information Act.

Long before Clinton -- the presumptive Democratic presidential nominee -- came under fire for setting up a do-it-yourself home email system when she was secretary of state, Canada's information commissioner raised concerns about electronic record-keeping.

In November 2013, Suzanne Legault urged the government to ban instant messaging on federally issued BlackBerrys and other wireless devices because such messages evaporate so quickly, erasing part of the government record.

In response to Legault's report, Treasury Board came up with a protocol for instant messaging that allows public servants to delete messages that "do not have business value."

The new protocol also recommended that departments and agencies stop electronically saving instant messages, though it is not clear how many have done so.

"For details relating to information management practices in specific departments, please contact them directly," Treasury Board spokeswoman Lisa Murphy wrote in an email.

But at least one prominent department has adopted the practice.

The Toronto Star reported in December that the Canada Revenue Agency had destroyed all text message records of its employees and stopped electronically saving such messages.

The newspaper cited documents released under the Access to Information Act that said Shared Services Canada -- the federal organization responsible for information technology services -- had wiped the records last August.

That revelation prompted a complaint to information commissioner Suzanne Legault's office from New Democrat MP Charlie Angus.

Asked how the government would know if one of its workers did not archive work-related instant messages, Murphy replied that public servants "are professional and take the preservation of the public trust seriously."

"The government expects that all public servants and staffers will respect the requirements to protect the information of business value," Murphy wrote in an email.

"Training and awareness on employees' responsibilities for record keeping is a requirement of the directive on record keeping."

Meanwhile, Angus also recently asked Legault's office to investigate a former Conservative ministerial staffer's systematic deletion of emails.

A recently published ethics commissioner's report found that Michael Bonner, a senior policy adviser to Jason Kenney in 2013 when he served as minister of employment and social development, deleted his electronic messages every two weeks. Kenney is now defence minister.