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Securely Storing Opt-Out Email Addresses

8 points by mbrubeck 16y ago

phillijw 16y ago
Considering the limits of a valid email address, I really doubt hashing would work as well as you think. You can effectively guess most of the words in the hash and you can be certain there will be somethingA@somethingB.somethingC. You can narrow down the list of possible domain names and assume most will likely be gmail, hotmail, yahoo, or something like that. This just doesn't seem like a very good solution and certainly not worth having on HN for such a short explanation. Not to mention, I doubt Walgreens is that concerned with the security of people who opt out of their emails.
win_ini 16y ago
This isn't really storing emails securely (in fact it reduces security in some cases - such as password resets) Most organizations have bigger email list problems than this - they are keeping email lists in spreadsheets, and other accesible places. In addition, those addresses may be needed for operational purposes - such as notifying some Customers of a breach or recalls on products. Emailing someone for either of these scenarios are not viewed as "Spam" by CAN-SPAM. in addition, you need a record of opt-outs to be CAN-SPAM compliant...using this technique actually makes you non-compliant. In the end, the best thing to do is use a proper email provider or marketing automation vendor that can properly allow you to setup emailing preferences and opt-outs (and can enforce adding unsubscribe links, etc to ALL your emails). These systems store the date/time and IP address of the computer that opted out for compliance reasons. Finally - these systems generally will aggressively SUPPRESS from sending to unsubscribed users (even so far as preventing sending the same email twice accidentally) by marketing users accidentally. While the stored email opt-outs can be used if hacked into - I would assume this would be just as bad as getting the rest of your list....in the end this is kind of security through obfuscation. The best remedy is to store ALL your email addresses in a secure, audited system that is protected properly and enforces email best practices across an organization.

8 points by mbrubeck 16y ago

Considering the limits of a valid email address, I really doubt hashing would work as well as you think. You can effectively guess most of the words in the hash and you can be certain there will be somethingA@somethingB.somethingC. You can narrow down the list of possible domain names and assume most will likely be gmail, hotmail, yahoo, or something like that. This just doesn't seem like a very good solution and certainly not worth having on HN for such a short explanation. Not to mention, I doubt Walgreens is that concerned with the security of people who opt out of their emails.

win_ini 16y ago

This isn't really storing emails securely (in fact it reduces security in some cases - such as password resets) Most organizations have bigger email list problems than this - they are keeping email lists in spreadsheets, and other accesible places. In addition, those addresses may be needed for operational purposes - such as notifying some Customers of a breach or recalls on products. Emailing someone for either of these scenarios are not viewed as "Spam" by CAN-SPAM. in addition, you need a record of opt-outs to be CAN-SPAM compliant...using this technique actually makes you non-compliant. In the end, the best thing to do is use a proper email provider or marketing automation vendor that can properly allow you to setup emailing preferences and opt-outs (and can enforce adding unsubscribe links, etc to ALL your emails). These systems store the date/time and IP address of the computer that opted out for compliance reasons. Finally - these systems generally will aggressively SUPPRESS from sending to unsubscribed users (even so far as preventing sending the same email twice accidentally) by marketing users accidentally. While the stored email opt-outs can be used if hacked into - I would assume this would be just as bad as getting the rest of your list....in the end this is kind of security through obfuscation. The best remedy is to store ALL your email addresses in a secure, audited system that is protected properly and enforces email best practices across an organization.