Contacting David Benfell

Updated March 31, 2017.

I am David Benfell. My identity is established on My vcard is available on my profile page.

There are numerous ways of reaching me, with varying degrees of security.

Directory of more secure means

I am accessible through numerous end-to-end encryption technologies. In addition, all web, email, and XMPP traffic to this server may be protected with a class 2 SSL certificate issued by a generally recognized authority and with a 4096-bit key (the usual length is 2048). The web security rating of this site or of any site may be checked using the Qualys SSL Labs SSL Server Test.


Signal on smartphone; susceptible to traffic analysis

+1-707-824-1194 - this service uses one's regular cell phone number.
XMPP on all devices: vulnerable to traffic analysis. S2S (server-to-server) and C2S (client-to-server) SSL security has been discontinued for security reasons. Use instead.
S/MIME: e-mail and web client identity verification, can be used for encryption, even more susceptible to traffic analysis via certificate authority.Class 2 PKCS#7 certificate or intermediate and personal certificates. Both the intermediate and personal certificates are necessary. The PKCS#7 certificate includes both.

Secure Communication

The most secure known communication programs are encrypted peer-to-peer with no central authority. Unfortunately, my current setup supports these poorly.

Encrypted, But Less Secure Communication

These means are vulnerable to traffic analysis.


I am on Skype as greybeard95a, but I rarely run it, it almost certainly has a backdoor, and it should not be used. Signal (both voice and SMS) are encrypted end-to-end, using my normal cell phone number, +1 707-824-1194.

XMPP chat (instant messaging)

I do not use OTR (Off-The-Record) encryption on XMPP because I use XMPP on multiple devices, some of which do not support OTR, and because a message encrypted via OTR for one device will, as near as I can determine, not be readable on another device. However, I have implemented SSL for contact via my XMPP server and I require it for server-to-server (s2s) connections; if the server for your account does not support this, then you will not be able to contact me by with XMPP. While I am present on a number of instant messaging services, including Facebook and Google-plus, I do not have my XMPP clients configured to use them. Reach me via XMPP at

XMPP may be the most efficient way of reaching me when I'm on the road, on par with an SMS message to my phone, but without the message length restriction or cellular fees. I suggest the Pidgin instant messaging client or, for Android devices, Xabber or Yaxim.

Non-secured Communication

Social Networks

The security of so-called "private" communications via centralized networks, such as Facebook and Twitter, should be considered compromised. Decentralized networks are better.

If I do not know you, it is probably best to contact me via a social network I use often such as Facebook (my profile).


If you wish to send me an e-mail, and I already know you and will recognize your name, make sure that it appears in the From: header of your email to or to This is a normal configuration detail and should present no difficulty in the majority of cases. Please do not encrypt messages using GnuPG/PGP; I am no longer able to decrypt messages sent using my long-established key. Be aware that I have implemented grey-listing as part of my spam defenses and that messages may be significantly delayed.


Candorville, May 14, 2016, via GoComics, fair use. My cell phone number is +1-707-824-1194. I do use Call Control: if you are on that app's community black list, or if you withhold your Caller ID, or if you call from a toll-free number, your call will be automatically blocked. My phone numbers are all listed on the National Do Not Call registry. I have voicemail turned off; it should not be offered to you. I rely on Caller ID to know whose calls I should answer and whom I should call back; if I do not recognize you and am not expecting your call, I will probably reject it.

My snail mail address is:


321 S. Main St. #12
Sebastopol, California 95472

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