Privacy in the digital age: phones, data and new technology

When Desjardins started policing, the most private thing most suspects carried was a wallet. Today, Linh Tran points out, nearly every person officers meet carries a phone holding years of messages, photos, location history, banking records, medical searches and the details of every relationship they have. Desjardins agrees and says that is why courts on both sides of the border have spent the last fifteen years rewriting the law of search for the digital age. Rules designed for wallets, filing cabinets and car trunks do not fit a device that can reveal more about a person than a search of their entire home. This lesson covers how courts have adapted section 8 to phones, computers, data held by companies and new surveillance tools.

Why digital devices are different

Courts have identified several features that make digital searches unusual. Phones and computers store an immense quantity of information, far more than any physical container. The information is intimate, revealing beliefs, health, finances and relationships. It reaches back over time, so a search can reconstruct years of a life. Much of it is not stored on the device at all but in the cloud, so looking at the phone can mean looking at data held on servers anywhere in the world. And the information is created automatically, often without the person knowing, as with location records and app logs. In R. v. Morelli in 2010, the Supreme Court said it is difficult to imagine a more intrusive invasion of privacy than the search of a personal computer, and in R. v. Vu in 2013 it held that a warrant to search a home does not automatically authorize searching the computers found there: police need specific authorization.

Searching a phone after arrest

In R. v. Fearon in 2014, a majority of the Supreme Court held that police may search a cell phone incident to a lawful arrest, but only under strict conditions. The arrest must be lawful. The search must be truly incidental to the arrest, for a valid purpose such as protecting officers or the public, preserving evidence or discovering evidence, and in the case of discovering evidence the investigation would be stymied or significantly hampered without a prompt search. The nature and extent of the search must be tailored to that purpose, which usually means looking only at recently sent or drafted messages, recent photos and the call log. And police must make detailed notes of what they examined, how and why. Outside those limits, police need a warrant.

Marco DiSanto asks why the two countries came out differently. Desjardins explains that the courts weighed the same considerations, the intrusiveness of the search against the needs of an urgent investigation, and drew the line in slightly different places. The Canadian majority allowed a narrow, carefully documented look in limited circumstances, while the dissenting judges would have required a warrant except in urgent situations. In practice, many Canadian services now advise officers to seize the phone and get a warrant unless there is a real urgency. For officers on either side, the safest habit is the same: secure the phone, prevent remote wiping, and seek a warrant.

Data held by others

Much of the information police want is held not by the suspect but by companies: phone carriers, internet providers, banks, app developers and cloud services. Canadian courts have rejected the idea that sharing information with a company ends a person's expectation of privacy. In R. v. Spencer in 2014, the Supreme Court held that police needed a warrant or production order to obtain the name and address of the subscriber linked to an internet address, because that link could reveal a person's online activity. In R. v. Bykovets in 2024, it went further and held that the internet address itself attracts a reasonable expectation of privacy, so police need judicial authorization to obtain IP addresses from third parties such as online payment processors. In R. v. Marakah in 2017, the Court held that a sender of text messages can have a reasonable expectation of privacy in messages found on the recipient's phone. The Criminal Code provides tools for this data: production orders, transmission data warrants and tracking warrants, each requiring a judge's approval.

Priya asks whether police can simply buy data that companies sell to anyone. Desjardins says this is one of the most contested questions in the field. Data brokers sell location and browsing information gathered from apps, and some agencies have purchased it. Privacy commissioners and courts in Canada have been skeptical; after the federal Privacy Commissioner found in 2021 that the RCMP's use of the Clearview AI facial recognition service violated the Privacy Act, the RCMP changed its practices. Officers should treat any new data source as a legal question first and a technical question second.

Surveillance technology

New tools raise the same basic question: does the technique intrude on a reasonable expectation of privacy? In R. v. Tessling in 2004, the Supreme Court held that using a thermal imaging camera from an aircraft to detect heat escaping from a house was not a search, because the heat pattern revealed nothing meaningful about the activities inside. Later cases have been more protective as technology improved, and the Court has emphasized that the analysis must consider what the technology is capable of revealing, not just what it showed in the particular case. Tracking a vehicle requires a tracking warrant, and real-time interception of private communications requires a wiretap authorization under Part VI of the Criminal Code, the most demanding order in Canadian law.

Some technologies sit in a grey zone that law and policy are still sorting out. Automated licence plate readers photograph every plate that passes and store the time and location. Drones can watch backyards from above. Facial recognition can match a face in a crowd to a database. Body-worn cameras record not only suspects but bystanders and the insides of homes. Canadian services have generally adopted these tools under policies reviewed by privacy commissioners, and courts look at how much the data reveals when combined over time. Desjardins advises the class to learn their service's policy for each tool and to remember that the policy is a floor, not a ceiling: the Charter still applies.

Tailoring a digital search

Even with a warrant, a digital search must stay within its authorization. Investigators increasingly use extraction tools that copy everything from a phone, but the warrant usually authorizes searching only for specific evidence, often within a time window. Detective Ana Ferreira of Port Ardent's major crime unit shows the class how investigators filter an extraction so that the review stays within the warrant. The program below represents a small extract and keeps only items within the authorized date range and categories.

# A simplified phone extraction: (day of March 2026, category, description)
items = [
    (2, "photo", "family dinner"), (9, "message", "work schedule"),
    (13, "message", "meet at the store tonight?"), (13, "photo", "street at night"),
    (14, "message", "got the stuff, 3 drills"), (14, "location", "near store 02:10"),
    (14, "browser", "medical symptoms search"), (15, "message", "how much for a drill?"),
    (20, "photo", "dog at the park"), (21, "message", "doctor appointment"),
]
# The warrant authorizes messages, photos and location from March 13 to 15 inclusive
allowed_days = range(13, 16)
allowed_categories = {"message", "photo", "location"}

in_scope = [i for i in items if i[0] in allowed_days and i[1] in allowed_categories]
print("items in extraction:", len(items))
print("items within the warrant:", len(in_scope))
for day, cat, desc in in_scope:
    print(f"  March {day}: {cat:8s} {desc}")
print("items the reviewer must not examine:", len(items) - len(in_scope))

items in extraction: 10
items within the warrant: 5
  March 13: message  meet at the store tonight?
  March 13: photo    street at night
  March 14: message  got the stuff, 3 drills
  March 14: location near store 02:10
  March 15: message  how much for a drill?
items the reviewer must not examine: 5

Of ten items, five fall within the warrant. The browser search on March 14 is inside the date range but outside the authorized categories, so the reviewer leaves it alone even though it is from the right day. Ferreira tells the class that reviewers document the filters they use, so that a court can see exactly what was examined. A reviewer who wanders through a whole phone because the extraction happens to contain everything turns a lawful warrant into an unreasonable search.

Passcodes, fingerprints and compelled access

A warrant may authorize searching a phone, but what if the phone is locked? Canadian courts have generally held that police cannot compel a suspect to provide a passcode, because doing so would conscript the person against themselves in breach of the principle against self-incrimination; investigators instead rely on forensic tools, other sources of the data, or the person's voluntary cooperation after legal advice. Using a suspect's fingerprint or face to unlock a device is less settled, and officers should seek legal advice and, where possible, specific judicial authorization before doing it.

Linh asks why a fingerprint might be treated differently from a passcode. Desjardins explains the distinction courts draw between physical evidence, which the privilege against self-incrimination generally does not protect, and communication from the mind, which it does. A passcode is something the person knows and must reveal; a fingerprint is something the person has. Whether unlocking a phone with a finger also communicates something, such as that the person controls the phone, is exactly what courts are debating.

Social media, open sources and undercover profiles

Information that people post publicly, such as open social media profiles, public comments and photos anyone can see, generally carries little or no reasonable expectation of privacy, and police can review it like any other public source. But open-source investigation has limits. Creating fake profiles to befriend a suspect, joining private groups and collecting large volumes of data about people who are not suspects can raise privacy issues, and in R. v. Mills in 2019 the Supreme Court held that an officer who posed as a child online to catch a predator did not need prior authorization only because the suspect had no reasonable expectation of privacy in messages to a stranger he believed was a child. Port Ardent requires supervisory approval and a written plan before any officer uses an online undercover identity.

Desjardins reminds the class that publicly available does not mean unlimited. Gathering every public post about a protest group, for example, can chill lawful expression, and privacy commissioners and courts have criticized mass collection of open-source data without a clear investigative purpose. Officers should collect what relates to a specific investigation, record why, and follow their service's policy.