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It's been a while since I worked with email headers and smtp, but I don't think the Bcc header actually exists in transit. The mail user agent and/or the mail s

by zerohp 13y ago

It's been a while since I worked with email headers and smtp, but I don't think the Bcc header actually exists in transit. The mail user agent and/or the mail submission agent remove it. They could reconstruct this information from the graph.

ChrisAntaki 13y ago
Considering they have an upstream wiretap on all US internet traffic, it seems possible they could determine the BCC.
- XorNot 13y ago
  Why bother? Google knows the BCC line - your email provider by definition has to in order to BCC the message, and it very much depends on them to properly scrub it out as well (I know for a while it was pretty trivial to see BCC's from most providers).
jlgreco 13y ago
Apparently not always: "In the second case, recipients specified in the "To:" and "CC:" lines each are sent a copy of the message with the "BCC:" line removed as above, but the recipients on the "BCC:" line get a separate copy of the message containing a "BCC:" line. (When there are multiple recipient addresses in the "BCC:" field, some implementations actually send a separate copy of the message to each recipient with a "BCC:" containing only the address of that particular recipient.)" http://en.wikipedia.org/wiki/Blind_carbon_copy#Visibility http://en.wikipedia.org/wiki/Blind_carbon_copy#Visibility Depending on combination and location of the MUA and MSA, it is plausible that the NSA was able to get full BCC lines.
tracker1 13y ago
It depends on if you get the envelop. The envelop is a list of recipients for a given server to handle... the headers of the actual email are a convenience for display, not used for relay/forward/delivery.
deleted 13y ago
[deleted]
fleitz 13y ago
The BCC field itself is usually removed from the email but if you're monitoring the STMP session you can reconstruct the BCC from the RCPT TO commands in SMTP.
- ape4 13y ago
  Yes if somebody is in the RCPT TO but not the To: or other fields then they are Bcc:

by zerohp 13y ago

ChrisAntaki 13y ago

Considering they have an upstream wiretap on all US internet traffic, it seems possible they could determine the BCC.

XorNot 13y ago
Why bother? Google knows the BCC line - your email provider by definition has to in order to BCC the message, and it very much depends on them to properly scrub it out as well (I know for a while it was pretty trivial to see BCC's from most providers).

jlgreco 13y ago

Apparently not always: "In the second case, recipients specified in the "To:" and "CC:" lines each are sent a copy of the message with the "BCC:" line removed as above, but the recipients on the "BCC:" line get a separate copy of the message containing a "BCC:" line. (When there are multiple recipient addresses in the "BCC:" field, some implementations actually send a separate copy of the message to each recipient with a "BCC:" containing only the address of that particular recipient.)" http://en.wikipedia.org/wiki/Blind_carbon_copy#Visibility http://en.wikipedia.org/wiki/Blind_carbon_copy#Visibility Depending on combination and location of the MUA and MSA, it is plausible that the NSA was able to get full BCC lines.

tracker1 13y ago

It depends on if you get the envelop. The envelop is a list of recipients for a given server to handle... the headers of the actual email are a convenience for display, not used for relay/forward/delivery.

deleted 13y ago

[deleted]

fleitz 13y ago

The BCC field itself is usually removed from the email but if you're monitoring the STMP session you can reconstruct the BCC from the RCPT TO commands in SMTP.

ape4 13y ago
Yes if somebody is in the RCPT TO but not the To: or other fields then they are Bcc: