> An alternate scenario is that Eve is also not a threat, but is instead a business that doesn't want the liability of having certain material in the plain inside of its premises ever.
One great example of this Eve is https://mega.nz - by design their servers never have access to the encryption key for any uploaded file, and files are shared by including said key in the hash of the URL. This is done for perfect legal deniability of any material on the site. As long as you trust Mega to not alter their code (you can defend-in-depth against this with various methods, including running an open-source client), and you send sharing links only to trusted parties, the content of your data cannot be detected.
One great example of this Eve is https://mega.nz - by design their servers never have access to the encryption key for any uploaded file, and files are shared by including said key in the hash of the URL. This is done for perfect legal deniability of any material on the site. As long as you trust Mega to not alter their code (you can defend-in-depth against this with various methods, including running an open-source client), and you send sharing links only to trusted parties, the content of your data cannot be detected.
https://mega.nz/SecurityWhitepaper.pdf