Good article by the FSFE: "when deciding on trusting a party, you need to consider:

benevolence: the party doesn’t want to compromise your privacy and/or is itself affected
competence: the party is technically capable of protecting your privacy and identifying/fixing issues
integrity: the party cannot be bought, bribed or infiltrated by secret services or other malicious third parties" https://blogs.fsfe.org/h2/2016/05/31/why-privacy-is-more-than-crypto/ !privacy