They can ask you to provide the password if they have probable cause and if you refuse can you be charged with obstruction of justice?
The cops can ask you anything they want including to provide the password to your phone.
However, you absolutely do NOT have to provide your password to anything to the police. And under current Canadian law, a warrant to compel you to do so is essentially unenforceable and carries no penalty, even if they coulf get a Judge to sign off on one.
Here is a good and recent article on this very issue. Police Chiefs are lobbying the government to make it an offence not to comply with such a demand.
https://www.thestar.com/news/world/...egal-battle-over-your-cellphone-password.html
Protection against self-incrimination and your right to privacy and security of the person are fundamental Charter rights.
A password is considered a "product of your mind" and compelling you to disclose what is in your mind for the purposes of incriminating yourself is therefore protected by the Charter.
Your fingerprint, or breath sample or DNA sample are not products of your mind and are therefore compelling production of such is not protected under the Charter the same way a password is.