Like most social networks, Mastodon is not end-to-end encrypted. If you're sending sensitive info it's better to use a separate end-to-end encrypted messaging app.
Mastodon itself warns you about this if you are sending a DM through the web interface (see the screenshot).
More info about the risks and how to mitigate them in the guide at:
➡️ https://fedi.tips/is-mastodon-end-to-end-encrypted
TL:DR - Main risk is your server admin reading your DMs, but they would need techy skills to do this.
@FediTips
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I wonder how many Fedi users are using PGP or similar schemes.
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