Encoding Techniques Efficiency Study

JavaScript-based email encoders like our antispam encoder are based on the assumption that web crawlers are not sophisticated enough to be able to identify the email address they protects. Is this assumption correct?

It Is a Reasonable Assumption?

The huge share of the email adresses that appear on web pages are unprotected. If we assume someone was willing to construct a tool capable of extracting those few email addresses that are protected, they would have to make a substantial effort for a minute result. Moreover, this assumption is of little relevance in case the user challenge option of the encoder is used.

Empirical Study

We have performed a simple experiment to try to confirm this hypothesis. Over more than three years, email probes have been placed on several web pages. The pages chosen were all indexed by the major search engines and had external inbound links. Probes were valid email addresses, created for the purpose. Their high length, as well a the random character sequence they were composed of, made it practically impossible for them to be guessed (e.g. K0Qsva83sBYNIV1V5LvfxVbE8vKmJU@example.com). Whearas half of the probes placed on each page were protected, the other half were not.

Outcome

None of the protected addresses received any emails, whereas all the others have been harvested and spammed. The un-protected addresses started to receive spam after as little as two days.

Conclusion

To date (Feb 2006), the protection techniques employed in the encoder are efficient.