Canada
Practice Relating to Rule 65. Perfidy
Canada’s LOAC Manual (1999) states:
Acts inviting the confidence of adversaries and leading them to believe that they are entitled to protection or are obliged to grant protection under the LOAC,
with intent to betray that confidence, constitute perfidy. In other words, perfidy consists of committing a hostile act under the cover of a legal protection.

[emphasis in original]
Canada’s Code of Conduct (2001) provides: “Perfidy is a war crime.”
Canada’s LOAC Manual (2001) states that the concept of chivalry “refers to the conduct of armed conflict in accordance with certain recognized formalities and courtesies”. It adds that “the concept of chivalry is reflected in specific prohibitions such as those against dishonourable or treacherous conduct and against misuse of enemy flags or flags of truce.”
In its chapters on land warfare, air warfare and naval warfare, the manual provides:
It is prohibited to kill, injure or capture adversaries by resort to perfidy. Acts inviting the confidence of adversaries and leading them to believe that they are entitled to protection or are obliged to grant protection under the LOAC,
with intent to betray that confidence, constitute perfidy. In other words, perfidy consists of committing a hostile act under the cover of a legal protection.

[emphasis in original]
Rule 10 of Canada’s Code of Conduct (2005) states: “Perfidy is a war crime.”
In the lesson plan for that rule, perfidy is defined as:
Acts inviting the confidence of adversaries and leading them to believe that they are entitled to protection or are obliged to grant protection under the Law of Armed Conflict,
with intent to betray that confidence, constitute perfidy. In other words, perfidy consists of committing a hostile act under the cover of a legal protection (e.g., firing on a member of an opposing force who comes forward under the protection of a white flag).

[emphasis in original]