# Talk:Public-key cryptography

WikiProject Cryptography / Computer science  (Rated C-class, Top-importance)
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 To-do list for Public-key cryptography: Merge sections "How it Works" and "Description"

## Readers questions (Concepts that could use some clarification from contributors)

1. The article might be improved for a general audience by a single first sentence that states the goal of this technology, -the problem it is trying to solve, using specific but self contained language. For example, "The purpose of encryption is to sent a message from a sender to a receiver with only the receiver being able to read the contents." -perhaps this is wrong, but you get the idea. Some of us are not exactly sure since this is not our field.

2. Does this technology require that the sender and receiver already be in possession of the public and private keys? Or does this term and this discussion cover how that happens. It should be emphasized that the security arises more from how the two keys are created and securely delivered to each party, if that's true. The article could be improved by separating the discussion of how the keys are used to achieve encryption, from where they come from and how they are secured between the sender and receiver. :

3. It is not clear why one key is generated from the other, if the the math used to do so is chosen specifically to leave an untraceable link between the two keys. (why not used two really unrelated keys?) — Preceding unsigned comment added by Sharesmart (talkcontribs) 15:15, 14 January 2014 (UTC)

## Encryption flow chart diagram doesn't match article text

The second encryption flow chart diagram ("I will pay \$500") does not match the article text.

The diagram shows the private key used for encryption and public key used for decryption. However the article says the opposite: public key is used for encryption and private key for decryption.

The article says: "The publicly available encrypting-key is widely distributed, while the private decrypting-key is known only to its proprietor", also "a message encrypted with a recipient's public key cannot be decrypted by anyone except a possessor of the matching private key". Either the article or diagram need changing. I assume the diagram is wrong. Someone with expertise in this area needs to validate this and make the change. Joema (talk) 15:16, 10 April 2013 (UTC) joema

The diagram is wrong, i've removed it. Skippydo (talk) 03:23, 11 April 2013 (UTC)

## Actual Algorithm, simple example

such a long distracting article, and no algorithm So I'll just put this here. Learn by Example!

• All integers.
• 2 facilitating numbers are to be calculated in order to find the encrypt/decrypt keys. lets call them m,n
• message=6;

(1) choose two prime numbers (preferably huge)

```11,23
```

(2) define n=11*23

```           =253
```

(3) find this multiplier 10,22 ==> m = 220

(4) find encryption key

```   lowest non element in 220....==>3
```

(5) Encrypted message= 6^3 mod 253= 216

(6) find Decryption Key lowest value possible so that (220*value +1)/3 is integer; because (220*2+1)/3= 441 / 3 ==> 147

(7) Decrypt (encrypted message , decryption key)

```    216^147 mod 253 =....= 6
```

--Namaste@? 00:04, 18 November 2013 (UTC)

Your example is an example of the RSA algorithm, which is linked from this article. Since public key cryptography is about the general concept rather than RSA specifically and covers many different algorithms, it would be inappropriate to include that here. An equivalent example is in the linked article for that specific algorithm. —Quondum 00:25, 18 November 2013 (UTC)
Quondum, I couldn't disagree more...you're seriously claiming that an example exists which is both general and specific?? Or are you claiming that examples are inappropriate? This article suffers from a severe case of pomposity which makes it very difficult for someone who doesn't already understand the subject to learn anything. I agree with Diza, a simple example SHOULD be included, and a section titled "Examples" should OBVIOUSLY contain one or more (simple) examples - NOT links to other articles. A list of links is not "Examples" it is References or Reference Examples.Abitslow (talk) 17:26, 18 May 2014 (UTC)
The suggested example illustrates only the operation used in the RSA algorithm, and not the concept of public key cryptography, aside from the fact that encryption and decryption use a different key (which in itself is not a defining characteristic). The crucial aspect of public key cryptography is a one-way function, and the one-wayness is not illustrated by this example. In short, the example does not reasonably illustrate anything that the article is primarily about. This is adequately explained there, and linking to it is sufficient for those who want it – after all, WP is structured as a richly linked medium. Including the example would be undue clutter for the majority who use WP for what it is intended: a reference. In an article about multiplication, one does not give a simple example of addition (e.g. 1 + 1 = 2), one leaves that to the article on addition, and links to it, even though multiplication is built upon addition. An encyclopaedia is a reference, not a textbook. —Quondum 19:08, 18 May 2014 (UTC)

## Intro to Article needs some editing

I would do it myself but I know enough about public key technology to know how complex it is and that's about it, I'm not enough of a security guy to take a shot at editing this. But the intro doesn't correspond to Wiki standards. Articles are supposed to start with the name of the article in bold at the beginning. Also, the name of the article is Public-Key cryptography but the intro starts off talking about "asymetric" which is confusing to users. Either the article should be changed to be about assymetric algorithms or there should be an intro sentence that says something like "also known as asymetric algorithms because... The second one would be my suggestion. --MadScientistX11 (talk) 19:53, 28 April 2014 (UTC)

## Physical keys are a bad metaphor

"There's one key to lock the box. And a different key to unlock it. And the message is the box."

Maybe magic wands would be more apt? — Preceding unsigned comment added by 107.199.201.225 (talk) 05:07, 8 October 2014 (UTC)