diff options
| author | Kai Stevenson <kai@kaistevenson.com> | 2022-10-08 18:46:02 -0700 |
|---|---|---|
| committer | Kai Stevenson <kai@kaistevenson.com> | 2022-10-08 18:46:02 -0700 |
| commit | 186e9555d0a9fa1910b5db306f2b62674b45acea (patch) | |
| tree | fc3bf981288699652084b94b082735b9849bf2e9 /writing/cryptography.php | |
| parent | 7cdaa8b30fcd8ab333d11719dc4b280b28347a71 (diff) | |
applied PHP template to all pages, fixed some things
Diffstat (limited to 'writing/cryptography.php')
| -rw-r--r-- | writing/cryptography.php | 94 |
1 files changed, 45 insertions, 49 deletions
diff --git a/writing/cryptography.php b/writing/cryptography.php index 7fb73c0..6c36572 100644 --- a/writing/cryptography.php +++ b/writing/cryptography.php @@ -1,49 +1,45 @@ -<head>
- <link rel="stylesheet" href="/style.css">
- <link rel="icon" type="image/x-icon" href="/favicon.ico">
-</head>
-
-<body>
- <div class="contentpane">
- <h1>Principles of Crytography for Data Security | <a class="backbutton" href=".">[Back]</a></h1>
- <p>As the amount of life spent online continues to increase, a great deal of private information is naturally
- being transmitted: banking details, medical records, business correspondences. Where once these exchanges of
- data would have occured between a small set of individuals in a shared space, they now happen between
- continents, through hundreds of servers and over complex network infrastructures. It is a system that cannot
- be fully accounted for by any individual, and so the means of transmission are insecure--much like having a
- letter transmitted by a series of couriers, the data is liable to be intercepted or modified. And so both
- parties in the exchange take on a risk that may prohibit especially critical data from being sent.
- Cryptography is the study of data obfuscation--a means of making a message readable only by some. It is the
- answer to the question "when the means of transmission cannot be trusted, how can information be conveyed
- securely?</p>
- <p>There are two classes of encryption: symmetric and asymmetric. Symmetric encryption allows a message to be
- encoded and decoded with the same piece of information, or key. The ancient Caesar cipher is an example of
- this; an arbitrary number acting as the key was agreed upon by both parties, and every letter in the message
- was shifted through the alphabet by that amount. It could easily be decoded by anyone who knew the key by
- simply shifting the letters backward through the alphabet. Simple algorithms such as the Caesar cipher are
- vulnerable to various attacks due to the patterns that they create in the ciphertext. A given letter may
- always be encoded in the same way, meaning that the key could be compromised if the attacker gained access
- to the plaintext and ciphertext forms of the same message. And a message could be decrypted without the key
- by recognizing repeated patterns in the ciphertext representing common words. More advanced symmetric
- encryption methods--like the Advanced Encryption Standard (AES) algorithm, developed for the US National
- Institute of Standards and Technologies--disrupt patterns in the message to prevent these types of attacks.
- </p>
- <p>Symmetric encryption is an imperfect solution in the internet age. Because it requires both parties to know
- the same secret key, those parties must have a secure form of communication already established. In the days
- of Caesar, this key exchange could be performed confidentially by two individuals in close proximity. When
- encryption is used on the internet, it cannot be assumed that the communicating parties will have had any
- physical interactions--and it would be impractical to expect every new customer of an online banking service
- to perform a physical key exchange. Asymmetric encryption solves this problem by removing the key exchange.
- Instead of encrypting and decrypting a message with the same key, an asymmetric encryption algorithm has a
- keypair, comprising a public key, used for encrypting a message, and a private key, used for decrypting a
- message. The keys are so named because the private key is never shared, while the public key can be
- broadcast widely. </p>
- <p>Typically, it demands more processing power to encrypt and decrypt messages with an asymmetric encryption
- implementation than a comparable symmetric one. For this reason, it is desirable to use symmetric encryption
- for most communications. An asymmetric implementation such as the Rivest--Shamir--Adleman (RSA) system is
- used to perform the key exchange. One of the devices will broadcast its public RSA key to the other, which
- will respond by generating an AES key, encrypting it with that RSA key, and returning it. This method of key
- exchange is secure, even if every network packet is intercepted. Once the devices share an AES key, they can
- communicate with the more efficient symmetric encryption method.</p>
- </div>
-</body>
\ No newline at end of file +<?php
+$title = "Principles of Crytography for Data Security";
+require($_SERVER["DOCUMENT_ROOT"] . "/head.php");
+require($_SERVER["DOCUMENT_ROOT"] . "/header.php");
+?>
+<p>As the amount of life spent online continues to increase, a great deal of private information is naturally
+ being transmitted: banking details, medical records, business correspondences. Where once these exchanges of
+ data would have occured between a small set of individuals in a shared space, they now happen between
+ continents, through hundreds of servers and over complex network infrastructures. It is a system that cannot
+ be fully accounted for by any individual, and so the means of transmission are insecure--much like having a
+ letter transmitted by a series of couriers, the data is liable to be intercepted or modified. And so both
+ parties in the exchange take on a risk that may prohibit especially critical data from being sent.
+ Cryptography is the study of data obfuscation--a means of making a message readable only by some. It is the
+ answer to the question "when the means of transmission cannot be trusted, how can information be conveyed
+ securely?</p>
+<p>There are two classes of encryption: symmetric and asymmetric. Symmetric encryption allows a message to be
+ encoded and decoded with the same piece of information, or key. The ancient Caesar cipher is an example of
+ this; an arbitrary number acting as the key was agreed upon by both parties, and every letter in the message
+ was shifted through the alphabet by that amount. It could easily be decoded by anyone who knew the key by
+ simply shifting the letters backward through the alphabet. Simple algorithms such as the Caesar cipher are
+ vulnerable to various attacks due to the patterns that they create in the ciphertext. A given letter may
+ always be encoded in the same way, meaning that the key could be compromised if the attacker gained access
+ to the plaintext and ciphertext forms of the same message. And a message could be decrypted without the key
+ by recognizing repeated patterns in the ciphertext representing common words. More advanced symmetric
+ encryption methods--like the Advanced Encryption Standard (AES) algorithm, developed for the US National
+ Institute of Standards and Technologies--disrupt patterns in the message to prevent these types of attacks.
+</p>
+<p>Symmetric encryption is an imperfect solution in the internet age. Because it requires both parties to know
+ the same secret key, those parties must have a secure form of communication already established. In the days
+ of Caesar, this key exchange could be performed confidentially by two individuals in close proximity. When
+ encryption is used on the internet, it cannot be assumed that the communicating parties will have had any
+ physical interactions--and it would be impractical to expect every new customer of an online banking service
+ to perform a physical key exchange. Asymmetric encryption solves this problem by removing the key exchange.
+ Instead of encrypting and decrypting a message with the same key, an asymmetric encryption algorithm has a
+ keypair, comprising a public key, used for encrypting a message, and a private key, used for decrypting a
+ message. The keys are so named because the private key is never shared, while the public key can be
+ broadcast widely. </p>
+<p>Typically, it demands more processing power to encrypt and decrypt messages with an asymmetric encryption
+ implementation than a comparable symmetric one. For this reason, it is desirable to use symmetric encryption
+ for most communications. An asymmetric implementation such as the Rivest--Shamir--Adleman (RSA) system is
+ used to perform the key exchange. One of the devices will broadcast its public RSA key to the other, which
+ will respond by generating an AES key, encrypting it with that RSA key, and returning it. This method of key
+ exchange is secure, even if every network packet is intercepted. Once the devices share an AES key, they can
+ communicate with the more efficient symmetric encryption method.</p>
+<?php require($_SERVER["DOCUMENT_ROOT"] . "/footer.php"); ?>
\ No newline at end of file |