Verified answer

Hi Chris,

I'm not sure this is really a Yahoo Mail question but I'll give you my best answer anyway.

Encryption is not a one way function. For an email to be truly encrypted but also viewable by both parties, both parties would need to use the same encryption key. So, you'd need confirmation that your recipient is using the same encryption which is where certificates come in. You can find plenty of information on this on the internet just by searching 'encrypting emails.'

Hope that helps!