Rarely Available Photos!!

1) Tim Berners Lee -- Founder of the World Wide Web

2) Picture taken when Microsoft was started

3) Steve Woznaik(sitting) and Steve Jobs of APPLE Computers.

He was three months late in filing a name for the business because he didn't get any better name for his new company.

So one day he told to the staff: "If I'll not get better name by 5 o'clcok today, our company's name will be anything he likes..."

so at 5 o'clcok nobody comeup with better name, and he was eating
APPLE that time...

so he keep the name of the company 'Apple Computers'

4) Bill Hewlett(L) and Dave Packard(R) of HP.

Behind them in the picture is the famous HP Garage.

Bill Hewlett and Dave Packard tossed a coin to decide whether the company they founded would be called Hewlett-Packard or Packard-Hewlett.

And the winner was NOT Bill... the winner was Dave.

5) Ken Thompson (L)and Dennis Ritchie(R) ,creators of UNIX.

Dennis Ritchie improved on the B programming language and called it 'New B'.

B was created by Ken Thompson as a revision of the Bon programming language (named after his wife Bonnie)

He later called it C.

6) Larry Page(L) and Sergey Brin(R), founders of Google.

Google was originally named 'Googol'.

After founders (Stanford graduates) Sergey Brin and Larry Page presented their project to an angel investor...

they received a cheque made out to 'Google' !...

So they kept name as GOOGLE

7) Gordon Moore(L) and Bob Noyce(R) ,founders of Intel.

Bob Noyce and Gordon Moore wanted to name their new company 'Moore Noyce'.

But that was already trademarked by a hotel chain...

So they had to settle for an acronym of INTegrated ELectronics... INTEL

8) Andreas Bechtolsheim , Bill Joy, Scott Mc Nealy and Vinod Khosla of SUN(StanfordUniversity Network) MicroSystems.

Founded by four StanfordUniversity buddies.

Andreas Bechtolsheim built a microcomputer;
Vinod Khosla recruited him;
Scott McNealy to manufacture computers based on it;
and Bill Joy to develop a UNIX-based OS for the computer...

SUN is the acronym for Stanford University Network

9) Linus Torvalds of Linux Operating System Linus Torvalds originally used the Minix OS on his system which he replaced by his OS.

Hence the working name was Linux (Linus' Minix).

He thought the name to be too egotistical and planned to name it
Freax (free + freak + x).

His friend Ari Lemmk encouraged Linus to upload it to a network
so it could be easily downloaded.

Ari gave Linus a directory called linux on his FTP server,
as he did not like the name Freax.

Linus like that directory name and he kept the name of
his new OS to LINUX...

10) Picture taken when INFOSYS was started. This picture was found in the album of the clerk who took this picture...

The picture was with that clerk only because it was his birthday and he just told everyone to stand together at one place to take a pic.

He borrow a camera from his friend and as he can not tell any of his boss to take pic, so he took pic by himself... even it was his birthday.

Very old document...

click to enlarge..

Babington Postscript

Monoalphabetic Ciphers

With only 25 possible keys the Caesar cipher is far from secure.

If, instead, we can use a permutation of the alphabetic characters, then there are 26! or greater than 4 X 10^26 possible keys. This is 10 orders of magnitude greater than the key space for DES and would seem to eliminated brute-force techniques for cryptanalysis. Such an approach is referred to as a Monoalphabetic Substitution cipher.


Keeping it in similar words.. instead of encrypting the data by shifting the alphabets.. we redefine the alphabets with jumbled alphabets and then map the plain text accordingly to get the cipher text.


Since there are many keys in this method we may consider that this algorithm is strong.. but we are wrong..

This is because the redundancey in the english language. I the cryptanalyst knows the nature of the plaintext then the analyst can exploit the regularities of the language.

As a first step, the relative frequency of the letters can be determined and compared to a standard frequency distribution of English, such as shown.



If the message were long enough, this technique might be sufficient to get the plain text out of the cipher message.


This is the table indicating the letter frequency in different languages..

Letter	French	German	Spanish	Esperanto	Italian	Turkish	Swedish
a	7.636%	6.51%	12.53%	12.12%	11.74%	11.68%	9.3%
b	0.901%	1.89%	1.42%	0.98%	0.92%	2.95%	1.3%
c	3.260%	3.06%	4.68%	0.78%	4.5%	0.97%	1.3%
d	3.669%	5.08%	5.86%	3.04%	3.73%	4.87%	4.5%
e	14.715%	17.40%	13.68%	8.99%	11.79%	9.01%	9.9%
f	1.066%	1.66%	0.69%	1.03%	0.95%	0.44%	2.0%
g	0.866%	3.01%	1.01%	1.17%	1.64%	1.34%	3.3%
h	0.737%	4.76%	0.70%	0.38%	1.54%	1.14%	2.1%
i	7.529%	7.55%	6.25%	10.01%	11.28%	8.27%	5.1%
j	0.545%	0.27%	0.44%	3.50%	0.00%	0.01%	0.7%
k	0.049%	1.21%	0.00%	4.16%	0.00%	4.71%	3.2%
l	5.456%	3.44%	4.97%	6.14%	6.51%	5.75%	5.2%
m	2.968%	2.53%	3.15%	2.99%	2.51%	3.74%	3.5%
n	7.095%	9.78%	6.71%	7.96%	6.88%	7.23%	8.8%
o	5.378%	2.51%	8.68%	8.78%	9.83%	2.45%	4.1%
p	3.021%	0.79%	2.51%	2.74%	3.05%	0.79%	1.7%
q	1.362%	0.02%	0.88%	0.00%	0.51%	0	0.007%
r	6.553%	7.00%	6.87%	5.91%	6.37%	6.95%	8.3%
s	7.948%	7.27%	7.98%	6.09%	4.98%	2.95%	6.3%
t	7.244%	6.15%	4.63%	5.27%	5.62%	3.09%	8.7%
u	6.311%	4.35%	3.93%	3.18%	3.01%	3.43%	1.8%
v	1.628%	0.67%	0.90%	1.90%	2.10%	0.98%	2.4%
w	0.114%	1.89%	0.02%	0.00%	0.00%	0	0.03%
x	0.387%	0.03%	0.22%	0.00%	0.00%	0	0.1%
y	0.308%	0.04%	0.90%	0.00%	0.00%	3.37%	0.6%
z	0.136%	1.13%	0.52%	0.50%	0.49%	1.50%	0.02%
à	0.486%	0	0	0	11.74%	0	0.0%
å	0	0	0	0	0	0	1.6%
ä	0	0	0	0	0	0	2.1%
œ	0.018%	0	0	0	0	0	0
ç	0.085%	0	0	0	0	1.26%	0
ĉ	0	0	0	0.66%	0	0	0
è	0.271%	0	0	0	11.79%	0	0.0%
é	1.904%	0	0	0	11.79%	0	0.0%
ê	0.225%	0	0	0	0	0	0
ë	0.000%	0	0	0	0	0	0
ĝ	0	0	0	0.69%	0	0	0
ğ	0	0	0	0	0	1.13%	0
ĥ	0	0	0	0.02%	0	0	0
î	0.045%	0	0	0	0	0	0
ì	0	0	0	0	11.28%	0	0
ï	0.005%	0	0	0	0	0	0
ı	0	0	0	0	0	5.20%*	0
ĵ	0	0	0	0.12%	0	0	0
ñ	0	0	0.03	0	0	0	0
ò	0	0	0	0	9.83%	0	0
ö	0	0	0	0	0	0.87%	1.5%
ŝ	0	0	0	0.38%	0	0	0
ş	0	0	0	0	0	1.94%	0
ß	0	0.31%	0	0	0	0	0
ù	0.058%	0	0	0	3.01%	0	0
ŭ	0	0	0	0.52%	0	0	0
ü	0	0	0	0	0	1.99%	0

An example:

given ciphertext:

UZQSOVUOHXMOPVGPOZPEVSGZWSZOPFPESXUDBMETSXAIZ
VUEPHZHMDZSHZOWSFPAPPDTSVPQUZWYMXUZUHSX
EPYEPOPDZSZUFPOMBZWPFUPZHMDJUDTMOHMQ

1. count relative letter frequencies (see text)

2. guess P & Z are e and t

3. guess ZW is th and hence ZWP is the

4. proceeding with trial and error finally get:

it was disclosed yesterday that several informal but
direct contacts have been made with political
representatives of the viet cong in moscow

Caesar Cipher

This is the earliest know substitution cipher, and was know to be used by Julius Caesar and hence the name.

The procedure:

Each letter of the alphabet is shifted 3 letters down the stream.

Note that the alphabet is wrapped around, so that the letter following Z is A..



The transformation can be defined by listing as follows:

Plain: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cipher: D E F G H I J K L M N O P Q R S T U V W X Y Z A B C


The mathematical analysis can be given as:

encryption:

C = E ( k , p ) = ( p + k ) mod 26

where,

C -> Cipher output.
E -> Encryption.
p -> Letter to be shifted.
k -> No. of places to shift the letter. its value lies between 1 to 25

decryption:

p = D ( k , c ) = ( c - k ) mod 26

where,

D -> Decryption.

an example:

Plaintext:  the quick brown fox jumps over the lazy dog

Ciphertext: WKH TXLFN EURZQ IRA MXPSV RYHU WKH ODCB GRJ

Problems with Caesar Cipher:

• The encryption and the decryption methods are known to everyone.
• There are only 25 keys to try the brute force attack.
• The language of the plaintext is know and easily recognizable.
  

Symmetric Ciphers

The most important tool for communication now-a-days is encryption.

There are 2 forms of encryption methods :

1. Conventional, or Symmetric encryption.

2. Public-Key, or Asymmetric encryption.


Symmetric Encryption:

Symmetric encryption is a form of cryptosystem in which encryption and decryption are performed using the same key. It is also know as conventional encryption.

This method transforms plain text into ciphertext using a secret key and an encryption algorithm. Using the same key and decryption algorithm, the plain text is recovered from the cipher text.

This is a traditional form which use substitution or transposition techniques. Substitution techniques map plain text elements into ciphertext elements. Transposition techniques systematically transpose the position of plaintext elements.

Egs:

1. Substitution Techniques.

• Caesar Cipher
• Monoalphabetic Ciphers
• Playfair Cipher
• One -Time Pad

2. Transposition Techniques.

3. Rotor Machines.

4. Steganography.

Two Rules and Brute - Force Attack

For any algorithm that is used for Cryptography, it must satisfy the two conditions or at the minimum one condition must atleast be satisfied.

They are:

1. The cost of breaking the Cipher should exceed the value of the Encrypted Information.

2. The time required to break the cipher should exceed the useful lifetime of the information.


Brute-Force Attack:


The method of using all the possible keys to get the intelligent plain text from cipher text is called the Brute-Force Attack.

This is the most commonly used attack.

For example: If a encryption method is performed with a key length of 2 bits, then there is a possibility of 4 keys.

in general this is represented as:

if the key length is of "n" bits,

then,

the number of possible keys is equal to 2^n.

dimensions of cryptography

With the use of Symmetric encryption, the principle security problem is maintaining the secrecy of the key..

Cryptology is the combination of Cryptography and Cryptanalys

There are 3 dimensions for cryptography:

1. Type of operation used for transforming plaintext to ciphertext.

In this there are two methods:

• Substitution - which means each element in the plain text is mapped into another element.
• Transposition - which means each element in the plain text is rearranged.

Most of the systems, which are also referred as product systems, involve multiple stages of substitution and transpositions.


2. Number of keys used.

if the same key is used by the sender and the receiver then it is called symmetric/single-key/secret-key/conventional encryption.


3. The way in which the plaintext is processed.

i.e. whether the data is processed in form of blocks (block cipher) or continuously (stream cipher)

Basic words

Let us understand some of the basic words used in cryptography..


1. Plain Text: An original Message which is used is called plain text.

2. Cipher Text: The encrypted message that is obtained when we encrypt the plain text is called cipher text.

3. Enciphering or Encryption: The process of converting from plain text to cipher text.

4. Deciphering or Decryption: The process of restoring the plain text from the cipher text.

5. Cryptanalysis: The techniques used for deciphering a message without any knowledge of the enciphering details.


Attacks on Encryption Algorithms:

The main objective of any attack on the cipher text would be to recover the key in the use rather than simply to recover the plain text. There are generally 2 approaches for this:

• Cryptanalysis : based on the properties of encryption algorithm.

• Brute-force attacks : The attacker tries all possible keys on a piece of cipher text.

History

CRYPTOGRAPHY
CRYPTOGRAPHY
CRYPTOGRAPHY
CRYPTOGRAPHY

Brief History:

Cryptography (or cryptology; derived from Greek κρυπτός kryptós "hidden," and γράφειν gráfein "to write") is a discipline of mathematics concerned with information security.

The History of Cryptography begins thousands of years ago. The earliest known use of cryptography is found in non-standard hieroglyphs carved into monuments from Egypt's Old Kingdom (ca 4500+ years ago). These are not thought to be serious attempts at secret communications, however, but rather to have been attempts at mystery, intrigue, or even amusement for literate onlookers.

Although cryptography has a long and complex history, it wasn't until the 19th century that it developed anything more than ad hoc approaches to either encryption or cryptanalysis (the science of finding weaknesses in crypto systems).

In 1917, Gilbert Vernam proposed a teletype cipher in which a previously-prepared key, kept on paper tape, is combined character by character with the plaintext message to produce the cyphertext. This led to the development of the one time pad and the use of electromechanical devices as cipher machines.

By World War II, mechanical and electromechanical cipher machines were in wide use, although — where such machines were impractical — manual systems continued in use. Great advances were made in cipher-breaking, all in secrecy. Information about this period has begun to be declassified as the official British 50-year secrecy period has come to an end, as U.S. archives have slowly opened, and as assorted memoirs and articles have appeared.


Some pictures of early machines used for Cryptography:

The Enigma machine was widely used by Nazi Germany; its cryptanalysis by the Allies provided vital Ultra intelligence.