How to transfer big (30GB) family videos without risk of getting into another hands?

My aunt asked me to send her some old family videos that I captured some years ago. They include births and family time that I wouldn't want to be floating around the web.

Is a service like transfernow dot net secure enough for this?

I was thinking of encrypting it with 7-zip with a long password, so even if it got out, it wouldn't be easily viewed.

I could also upgrade my free DropBox plan for a month to store …

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