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.