In case you wish to create single purpose email address for registration to Overgrow.com we have gathered list of temporary mail box services (listed by their popularity):
- www.bitmessage.ch (requires knowledge of blockchain/bitcoin)
www.hushmail.com(removed - see discussion below)
- www.tormail.org (available only through Tor network)
For more permanent security-minded inbox these services offer embedded PGP encryption:
If you prefer encryption in desktop mail client, you can check Enigmail - PGP extension to Mozilla Thunderbird.