Question:

I work during the day, and because I mostly use the Web at work, I don’t have an Internet connection of my own at home. Sometimes at night I like to check my e‑mails and browse the Internet. One of my neighbors has an open, unsecured wireless connection. Can I use his Wi-Fi without permission?

Response:

Before beginning a discussion about using unsecured Internet connections according to Jewish law, it must be noted that many countries and states have specific laws that prohibit accessing someone else’s computer or network without authorization. According to Jewish law, as long as civil law does not contradict Torah law, “the law of the country is the law,” and the halachah follows civil law.1 In New York State, for instance, unauthorized use of a computer network is considered a Class A misdemeanor.2

Therefore, any discussion on this topic from the perspective of Jewish law must be based on the assumption that civil law does not explicitly address it. Nevertheless, the question of using an unsecured network raises a number of halachic issues, and is worth delving into further.

Borrowing Without Permission

When you use your neighbor’s Wi-Fi, you are essentially “borrowing” his computer, router, modem and Internet connection without permission. The Talmud records a dispute among the sages as to whether one who borrows something without permission is considered a borrower or a thief.3 The halachah follows the opinion that this person is considered a thief, even if he or she intends to return the object afterward.4

There are exceptions to this rule, however. In cases where the object of “theft” is something that no one (not even a small number of people) would object to someone’s borrowing without permission, and there is no risk of damaging the object, halachah considers it permissible to use it without approval.5

Although accessing the Internet through an open Wi-Fi connection rarely causes damage to the network, it seems safe to assume that at least a small number of people would object to their Wi-Fi being used without permission, and doing so would be considered stealing.

There is, however, another reason why some say that using an open Wi-Fi network without permission would be permitted.

Objects of No Substance

When discussing the mitzvah of listening to the shofar on Rosh Hashanah, the halachah posits that if someone blew from a stolen shofar, he nevertheless fulfilled his obligation. The rationale in this case is that the laws of theft do not apply to entities without substance, like sight and sound.6

(It should be noted that there is a dispute about whether the reason one still fulfills his obligation is because the mitzvah is only to hear the sound of the shofar, and the laws of theft do not apply to sound alone, or because [unlike, for example, the mitzvah of lulav] there is no requirement that the shofar must belong to the one using it.7 The halachah follows the opinion that the reason is because the laws of theft do not apply to something without substance.8)

Based on this idea that things without substance cannot be stolen, it would seem that using a neighbor’s open Internet connection without permission would be permitted. However, other commentaries point out that stealing something without substance isn’t considered stealing because using that intangible object did not cause a loss to the owner. Should it cause a loss, it would certainly be considered damaging or stealing another person’s property.9

Generally, subscribers pay an Internet service provider (ISP) for a limited amount of access to the Internet, called bandwidth. The speed of an Internet connection depends on the amount of available bandwidth at a given time. Wider bandwidth allows more data to be sent and received simultaneously, resulting in faster Internet service. When a non-subscriber downloads large files using an open Internet connection while the subscriber is using the Internet, the reduced bandwidth can significantly slow the owner’s connection. In other words, this causes a loss to the neighbor.

Therefore, although an Internet connection may be classified as something without substance, if using it causes the owner a loss in any way, it would be prohibited to use it without permission. If one used the Internet in a way that had no effect on the owner’s speed, however, or at times when the neighbor isn’t using the Internet, it might be halachically permitted.10

Although less common, some service providers charge subscribers based on the amount of data used. In this case, using a neighbor’s Wi-Fi without permission could cause a loss regardless of the time of day, and using the open network would be prohibited without permission.

“This One Benefits . . .”

When discussing this issue, some rabbis refer to a well-known Talmudic concept that if “one person will benefit, and the other one suffers no loss,”11 you cannot hold the other person back from deriving that benefit.12 In fact, in some instances halachah forces the owner to allow the other person to derive that benefit.13 But as we explained above, in many instances using someone else’s Internet connection does indeed cause a loss to the owner. Therefore, this rationale would apply only in a scenario in which the owner does not suffer a loss.

So, to answer your question: If you live in a place where using an unsecured Internet connection without permission is permitted by civil law, and you can be sure that your using the Wi-Fi will not slow your neighbor’s connection, increase his bill or cause him any other kind of loss, halachah would theoretically permit you to use the Wi-Fi without permission. But why not play it safe? Knock on his door and ask him if he minds—it’s the neighborly thing to do.