Encryption - Revision history

Franks: typo

2008-02-06T01:51:05Z

typo

← Older revision		Revision as of 18:51, 5 February 2008
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	There are different types of encryption, symmetric and asymetric. Symetric encryption requires a secret key that is well known (or "shared") by everyone reading and writing the message (in our example, Alice and Bob). This is the form of encryption most people are familiar with. If someone else (Eve or Mallory) somehow learns the secret key, that person can read all of the messages encrypted with that key. The biggest weakness in most symetric encryption systems is how the [[key distribution\|shared key is distributed]].		There are different types of encryption, symmetric and asymetric. Symetric encryption requires a secret key that is well known (or "shared") by everyone reading and writing the message (in our example, Alice and Bob). This is the form of encryption most people are familiar with. If someone else (Eve or Mallory) somehow learns the secret key, that person can read all of the messages encrypted with that key. The biggest weakness in most symetric encryption systems is how the [[key distribution\|shared key is distributed]].

	In ~~anymetric~~ encryption, two different keys are used for encryption and decryption, removing many of the problems of key distribution. The most common form of asymetric encryption is known as [[public key]] encryption. If Bob doesn't have the secret key, he and Alice can use public encryption (asymetric) to work out a new key in a secure fashion. Public key encryption is subject to the [[Man in the middle]] attack, whereby Eve or Mallory intercepts the message from Alice to Bob, decrypts (and possibly alters) it, then re-encrypts the message with his ''own'' key, before sending it along to Bob.		In asymetric encryption, two different keys are used for encryption and decryption, removing many of the problems of key distribution. The most common form of asymetric encryption is known as [[public key]] encryption. If Bob doesn't have the secret key, he and Alice can use public encryption (asymetric) to work out a new key in a secure fashion. Public key encryption is subject to the [[Man in the middle]] attack, whereby Eve or Mallory intercepts the message from Alice to Bob, decrypts (and possibly alters) it, then re-encrypts the message with his ''own'' key, before sending it along to Bob.

	== Symmetric Encryption ==		== Symmetric Encryption ==

Hawson: Changes, linkage, etc

2008-02-05T16:05:31Z

Changes, linkage, etc

← Older revision		Revision as of 09:05, 5 February 2008
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	~~Encryption is the art of obfuscating information so that a third party cannot read its contents.~~		== Background==

	~~Meet Alice~~. ~~(person A)~~		Encryption is the art of obfuscating information so that a third party cannot read its contents. The encrypted text in encryption is called ciphertext. In plain text it's called plaintext.
	~~Meet Bob~~. ~~(person B)~~.

	Alice ~~likes Bob~~ and ~~wants to write~~ Bob ~~a loveletter~~.		Meet ''Alice'' and ''Bob''.

	Meet Eve. (the person that eavesdrops).		In most cryptography examples, Alice wants to send something to Bob. In our case, Alice likes Bob and wants to write him a loveletter.

			Meet Eve (the person that eavesdrops).
	Meet Mallory (the person that likes to destroy things).		Meet Mallory (the person that likes to destroy things).

	Eve and ~~Mallory want to know what Alice writes~~ to ~~Bob~~. Mallory wants to ~~go even further and anger~~ Alice ~~and Bob~~.		Eve loves gossip, and just wants to read the loveletter. Mallory is actually jealous of Alice, and not only wants to read the letter, but wants to make Bob mad at Alice.

	There is different types of encryption, symmetric and ~~assymetric~~. ~~Former one~~ requires a key that is well known ~~on both ends between~~ Alice and Bob.		There are different types of encryption, symmetric and asymetric. Symetric encryption requires a secret key that is well known (or "shared") by everyone reading and writing the message (in our example, Alice and Bob). This is the form of encryption most people are familiar with. If someone else (Eve or Mallory) somehow learns the secret key, that person can read all of the messages encrypted with that key. The biggest weakness in most symetric encryption systems is how the [[key distribution\|shared key is distributed]].
	If ~~Bob doesn't have~~ the secret key, ~~he and Alice~~ can ~~use public~~
	~~encryption (assymetric) to work out a new key in a secure fashion. Supposedly Eve cannot determine~~ the ~~new~~ key. ~~But Mallory can still get~~ in ~~the way by~~
	~~disrupting communication. At this point~~ encryption ~~won't help either~~
	~~and noone~~ is ~~any smarter about what~~ the key is ~~that Alice holds, not~~
	~~Bob, not Eve and especially not Mallory.~~

	~~The encrypted text in encryption is called ciphertext. In plain text it's~~
	~~called plaintext~~.

			In anymetric encryption, two different keys are used for encryption and decryption, removing many of the problems of key distribution. The most common form of asymetric encryption is known as [[public key]] encryption. If Bob doesn't have the secret key, he and Alice can use public encryption (asymetric) to work out a new key in a secure fashion. Public key encryption is subject to the [[Man in the middle]] attack, whereby Eve or Mallory intercepts the message from Alice to Bob, decrypts (and possibly alters) it, then re-encrypts the message with his ''own'' key, before sending it along to Bob.

	== Symmetric Encryption ==		== Symmetric Encryption ==
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	AES		AES
	Blowfish		Blowfish
			(and many others)

	Most of these are considered BLOCK ciphers because, as in Blowfish's case you can only encrypt a block of 8 bytes at a time.		Most of these are considered BLOCK ciphers because, as in Blowfish's case you can only encrypt a block of 8 bytes at a time.
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	== Asymmetric Encryption ==		== Asymmetric Encryption ==


	Diffie-Hellman exchange		Diffie-Hellman exchange
	RSA		RSA

			== Further reading ==

			; <u>Applied Cryptography</u> by Bruce Schneier : http://www.schneier.com/book-applied.html Currently ''the'' definative reference (unclassified, at least) on cryptography. The entire book is availabe in PDF form at this location: http://www.cacr.math.uwaterloo.ca/hac/

Pbug at 09:23, 1 February 2008

2008-02-01T09:23:54Z

← Older revision		Revision as of 02:23, 1 February 2008
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	The encrypted text in encryption is called ciphertext. In plain text it's		The encrypted text in encryption is called ciphertext. In plain text it's
	called plaintext.		called plaintext.


			== Symmetric Encryption ==

			There is several private key encryptions such as

			DES
			3DES
			AES
			Blowfish

			Most of these are considered BLOCK ciphers because, as in Blowfish's case you can only encrypt a block of 8 bytes at a time.

			Stream ciphers are opposite and encrypt a bit or byte at a time.

			RC4 - supposedly is a stream cipher.

			Private key or Symmetric encryption needs Alice and Bob to have the
			same key, perhaps negotiated last thursday when they had lunch together down at the Plaza, we saw Alice write the key on Bob's napkin.


			== Asymmetric Encryption ==


			Diffie-Hellman exchange
			RSA

Pbug at 21:03, 31 January 2008

2008-01-31T21:03:42Z

← Older revision		Revision as of 14:03, 31 January 2008
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	There is different types of encryption, symmetric and assymetric. Former one requires a key that is well known on both ends between Alice and Bob.		There is different types of encryption, symmetric and assymetric. Former one requires a key that is well known on both ends between Alice and Bob.
	If Bob doesn't have the secret key, he and Alice can use public		If Bob doesn't have the secret key, he and Alice can use public
	encryption to work out a new key in a secure fashion. Supposedly Eve cannot determine the new key. But Mallory can still get in the way by		encryption (assymetric) to work out a new key in a secure fashion. Supposedly Eve cannot determine the new key. But Mallory can still get in the way by
	disrupting communication. At this point encryption won't help either		disrupting communication. At this point encryption won't help either
	and noone is any smarter about what the key is that Alice holds, not		and noone is any smarter about what the key is that Alice holds, not

Pbug: former

2008-01-31T21:03:01Z

former

← Older revision		Revision as of 14:03, 31 January 2008
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	Eve and Mallory want to know what Alice writes to Bob. Mallory wants to go even further and anger Alice and Bob.		Eve and Mallory want to know what Alice writes to Bob. Mallory wants to go even further and anger Alice and Bob.

	There is different types of encryption, symmetric and assymetric. ~~One~~ requires a key that is well known on both ends between Alice and Bob.		There is different types of encryption, symmetric and assymetric. Former one requires a key that is well known on both ends between Alice and Bob.
	If Bob doesn't have the secret key, he and Alice can use public		If Bob doesn't have the secret key, he and Alice can use public
	encryption to work out a new key in a secure fashion. Supposedly Eve cannot determine the new key. But Mallory can still get in the way by		encryption to work out a new key in a secure fashion. Supposedly Eve cannot determine the new key. But Mallory can still get in the way by

Pbug: spaces

2008-01-31T21:00:43Z

spaces

← Older revision		Revision as of 14:00, 31 January 2008
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	Encryption is the art of obfuscating information so that a third party cannot read its contents.		Encryption is the art of obfuscating information so that a third party cannot read its contents.

	Meet Alice. (person A)		Meet Alice. (person A)
	Meet Bob. (person B).		Meet Bob. (person B).

	Alice likes Bob and wants to write Bob a loveletter.		Alice likes Bob and wants to write Bob a loveletter.

	Meet Eve. (the person that eavesdrops).		Meet Eve. (the person that eavesdrops).
	Meet Mallory (the person that likes to destroy things).		Meet Mallory (the person that likes to destroy things).

	Eve and Mallory want to know what Alice writes to Bob. Mallory wants to go even further and anger Alice and Bob.		Eve and Mallory want to know what Alice writes to Bob. Mallory wants to go even further and anger Alice and Bob.

Pbug: minor alice bob stuff

2008-01-31T20:25:48Z

minor alice bob stuff

New page

Encryption is the art of obfuscating information so that a third party cannot read its contents.

Meet Alice. (person A)
Meet Bob. (person B).

Alice likes Bob and wants to write Bob a loveletter.

Meet Eve. (the person that eavesdrops).
Meet Mallory (the person that likes to destroy things).

Eve and Mallory want to know what Alice writes to Bob. Mallory wants to go even further and anger Alice and Bob.

There is different types of encryption, symmetric and assymetric. One requires a key that is well known on both ends between Alice and Bob.
If Bob doesn't have the secret key, he and Alice can use public
encryption to work out a new key in a secure fashion. Supposedly Eve cannot determine the new key. But Mallory can still get in the way by
disrupting communication. At this point encryption won't help either
and noone is any smarter about what the key is that Alice holds, not
Bob, not Eve and especially not Mallory.

The encrypted text in encryption is called ciphertext. In plain text it's
called plaintext.