Friday, 3 June 2011
1) Installing fedora

1st create partition for root drive, then create partition for home drive, then /drive and finally swap drive

Swap space: swap, put it somewhere else, so to have space.

2) Installing on thumbdrive

C: 3rd drive, SDC: 3rd drive, SDA: 1st drive, SDB: 2nd drive etc
Master boot record: MBR,

3) Creating your own PGP/GPG key

PGP: pretty good privacy
GPG: GNU Privacy Guide

Public key infrastructure: if i want to send a secret msg to someone else, how to ensure, only that somebody is the only one thats able to see? Without the rest being able to see. Thus, all these, is under cryptography: field to encrypt. Encrypt to hide details.

EG
Actual msg: D E A D
but dont send the actual message
everytime see a D, change to F.. E change to G.. so msg sent becomes: FGCF, if ppl reverse process it, can encode the message as DEAD.

A string of words: key
WIFI: key easy to break, so can somehow 'read' the msg, WPA: abit harder, a few days to break

PKI: Public Key Infrastructure
use alrogrithm, create 2 number, use one of the numbers to generate public key that is sent, everyone can see. Then give the other number, use it as a private key, to somebody u want to read your msg, that person can then use it to reverse it to get the actual msg. relationship between the 2 number is a fixed relationship.

EXAMPLE

have 2 very large numbers eg A and B, numbers related to each other. Relationship comes from the algorithm that it was run.

Eg actual MSG: HELP ME, then add it to number A, creates some key eg XYZABC12345, that is now sent. cannot use number A to do reverse.

So to figure out what is the actual msg, do same actual math formula, but instead of number A, use number B, then output will be : HELP ME
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*prime no. is the basis of PKI* relationship between the 2 keys is due to algorithm that is possible becos of prime no.
*also the length of the key is impt. Measured by no. of bits. Eg private key is only 2 numbers/ 2 bits:10, only 4 possibilities: 01,10,00,11.
The more the bits, longer the key, more possibilities, more likely your key is valid cos it takes longer for ppl to break the key. Can use brute force method, but how long
Brute force method: the way of breaking the key. Where it goes thru all the possible combinations to solve it.

*ENCRYPT: 1st objective: u know who send the msg to you
2nd objective: ensure u are the only person that reads it, guarentee, only receiver can see it
Here, authenticating each other!

Eg Person 1 wants to send msg to Person 2, only person 2 can read it. Take actual msg, take private key, create a public key. Then take person 2 public key, apply onto your msg, get the output, send the output to the person 2 u want to read your msg. Person 2 takes the output plus the private key, reverse process, gets the actual msg.

If dont take care of private key, then everyone have access to your actual msg. Only give your private key to the person u want to read the msg. Private key is something like your password.
This is one way, u know for sure, the msg come from the person who gives the private key to you. Its like a digital signature.

- HTTPS: the S is the secure part.
- basis of PKI: can have electronic commerce

SUMMARY OF PKI

Basically, it is a scheme to allow for the deployment of an electronic means to sign documents for authenticity checks.

Rivest Shamir Adleman (RDA) came up with a method in 1970s, widely acknowledged as the first alogarithm for PKI and is used in e-commerce.

The magic of this method centers on the use of two large prime numbers which act as your keys. One will be the public key, and one will be held secret and safe as the private key.
The advantage of this is the not only do you gain ability to encrypt, preventing authorized access, you will not be giving away your unique private key, hence providing a method of determining "sender identity".

2 scenarios: first, one that u use ur private key to encrypt something, and the receiver uses your public key to open it. another scenario could be that you want to designate a specific recipient, hence you apply both your own private key and the public key of the recipient, then you send it, the mail can only be opened with knowledge of both your public key and his own private key.

Hence this ensures 3 things, that only the recipient can see it, recipient is sure of sender identity and there was no content loss in the process of sending.

Crytography is about the size in the sense that the number of bits determine the difficulty of "cracking" the code or, the strength of the keys (in binary: 0 and 1).

The "Brute Force Method" is the way of cracking where the cracker goes through all the possible combinations to solve it.
In the addition of an additional bit will double the time take to solve it. (number of combinations = 2^n, where n=no. of bits). In technology, 1024,2048 and 4096bits are commonly applied. ALOT OF TIME to go through all the possible combinations,

- 2 main software in the opensource side, namely the PGP(pretty good privacy) and the GPG(gnu privacy guard).

One example of PKI is our EZ LINK card, in which a "private" key is embedded and signed by the card provider (NETS, EZlink or others). When the card is tapped, in the milliseconds of contact, the card is activated and the required information is retrieved from the card to verify the fund available for use. Net trust company: creates the private key of ez link.

Certificate authority (CA): In cryptography, a certificate authority or certification authority (CA) is an entity that issues digital certificates. The digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon signatures or assertions made by the private key that corresponds to the public key that is certified. In this model of trust relationships, a CA is a trusted third party that is trusted by both the subject (owner) of the certificate and the party relying upon the certificate. CAs are characteristic of many public key infrastructure (PKI) schemes.

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PGP: PGP(pretty good privacy) and the GPG(gnu privacy guard). In the 1990s, Us legislation classified crytography as a munition and hence any distribution to outside of the US was illegal. Philip Zimmermann of PGP fame decided to circumvent this by using a loophole in the right to free speech act to publish the code in a book using fonts that be be easily read and transcribed to computers. This allowed the PGP code to be available to everyone in the world.


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