Limiter la police à chercher le nom des fichiers, des dossiers ou de la valeur de hachage dans sa fouille d'un support informatique crée des angles morts inacceptables

R. v. John, 2018 ONCA 702 

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[23] As this court noted in R. v. Jones (2011), 107 O.R. (3d) 241, [2011] O.J. No. 4388, 2011 ONCA 632, at paras. 43-44:

The focus on the type of evidence being sought, as opposed to the type of files that may be examined is helpful, it seems to me, particularly in cases where it may be necessary for the police to do a wide-ranging inspection of the contents of the computer in order to ensure that evidence has not been concealed or its resting place in the bowels of the computer cleverly camouflaged.

To the extent they are required to examine any file or folder on the computer to reasonably accomplish that authorized search, the police are entitled to open those files and folders and to examine them, at least in a cursory fashion, in order to determine whether they are likely to contain evidence of the type they are seeking.

(Citations omitted)

[24] I do not accept the argument that there must be prior evidence of concealment of incriminating evidence before police can look at all images and videos stored on a computer in this kind of investigation where some child pornography has been located on the computer on initial examination. Rather, a search of all images and videos is appropriate in an investigation like this precisely to determine whether there is more child pornography on the computer. To limit police to searches by hash values, file names and download folders would be to provide a roadmap for concealment of files containing child pornography.

[25] I also do not accept the argument that the search was overbroad because it was not tailored to a date range in terms of the files searched. Here the police were looking for images and videos of child pornography and evidence that might show who was responsible for that content. This was not a broad search of multiple devices or large amounts of data unrelated to the specific investigation, such as in R. v. Sop, [2014] O.J. No. 3666, 2014 ONSC 4610 (S.C.J.), at paras. 116-149; or R. v. Marek, [2016] A.J. No. 24, 2016 ABQB 18, at paras. 120-147.

[26] Finally, I reject the argument that the search of all images and videos here was overly invasive because the vast majority of the offending material would have been located using a combination of hash value comparison, keyword searching of file name and [page678] searching the file folders most likely to contain child pornography. This argument fails because it uses the ultimate results or fruits of the search to dictate whether the scope of the search was reasonable. Given the limitations of searching only by hash value or file or folder name discussed above, hindsight should not be used in this way to turn what was once a reasonable search in all the circumstances into an unreasonable one.