Cryptography

The History and Mathematics of Codes and Code Breaking

Tag: web

Oh What a Tangled Web

A Tricky Web of Trust

The passage in Little Brother that really intrigued me was the passage about “a web of trust” found on pages 153 and 154. The previous passage talked about public keys versus private keys and the risks associated with these keys. It is very difficult to make the public key incredibly public and a middle man can easily confuse the two people trying to communicate by secretly intercepting, reading and changing messages. The only way to ensure that communication is secure is to meet in person and swap keys, thus creating a secure web of trust limited by the pure number of people you can meet up with in person. However, if people keep passing on all of their keys to people they trust the ring grows and encompasses a larger group where secure communication is possible.

I think this is incredibly interesting since it seems then that any terrorist or criminal group would use this to communicate. Most partners in crime meet in person and would be able to devise such a plan to evade any potential middle men trying to intercept their communications. The passage seems to say that if you trust someone enough and see him or her in person, you can absolutely ensure safe communication with him or her. This ties into our discussions on whether the cryptographers or decrypters are winning and if such strong cryptos should even be allowed. In this case, the passage seems to be claiming that cryptographers will always win if they employ this strategy. This leads to questioning whether these encrypted messages are truly protecting innocent people or if they are masking and hiding criminals and terrorists. The argument could beOh What a Tangled Web made that cryptography that is unbreakable unless trust is broken is considered too strong and can be used too easily for harm. While this cryptography method may be used to protect individual’s privacy, I assume it would also be used to enable dangerous communication and activity.

 

Image: Oh What a Tangled Web by Jenny Downing, Flickr (CC)

Emotion vs. Logic: The Web of Trust

In Cory Doctorow’s novel, Little Brother, the protagonist Marcus Yallow and his comrades form a web of trust as a response to the DHS’s infiltration of the Xnet. The concept of a web of trust intrigued me. As a product of cryptography, the web of trust relies heavily on the actual trust between individuals and less so on the complexity of the cipher. The biggest weakness of the web of trust is not that the cipher can be broken, but that the people involved may be untrustworthy. In addition, one untrustworthy person can compromise the entire web because each person holds the others’ keys.  The danger of the web of trust is illustrated with Masha’s threat that she can compromise the whole web of trust because she is a part of it.

Another aspect of the web of trust that I found interesting was that it required the participants to meet in person. Although it reduces the convenience and accessibility of the web of trust, it greatly increases its security. As mentioned in the novel, public-key cryptography is vulnerable to the man-in-the-middle (in Marcus’s case, the DHS) and could result in the unknown interception and decryption of incriminating messages. With the web of trust, only those in the web have access to the public keys, and therefore all the messages received by others from the web are guaranteed to be legitimate.

The logic and encryption behind the web of trust is invincible to decryption. The intelligence of a cryptanalyst is irrelevant to breaking a web of trust; in fact, exploiting the instability of human relationships is the only method in which the web can be broken. Because the web’s security relies on human emotion and the trust between individuals, it could actually be potentially weaker than other forms of cryptography. The fickle nature of trust formed between friends and colleagues is a risk that could possibly equal the mathematical vulnerability of other ciphers.

Image: “wide web,” by josef.stuefer, Flickr (CC)

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