The Security of EL GAMAL

some people ask me, it is posibble to break EL Gamal Cryptosytem...i said, that everything is posibble in the Computer World...But to break El Gamal it have a long way and a long time... El Gamal Security have a discrete problem. but i have some tips how to analyze the El gamal Strength... this way not to break and use to crime..but to give us some known, to make our El Gamal Criptosystem better strength....

 ElGamal is very secure. The only ways to break it are by finding collisions in the hash functions it uses, or (in theory) by computing the secret key when two ciphertext messages are sent with the same function of the secret exponent. See Wikipedia for more details

You can do what I do when using safe (p=2p'+1) prime moduli, which is to 
convert the plaintext to all QR's so semantic security is preserved - 
although this is in effect working in the subgroup of QR's of order p', 
which is presumed DDH-hard. 



Which is just a feeble excuse :) to present this method of ensuring all the 
bits are QR's, and the overall scheme is IND-CPA. I don't know who else 
invented the method first, but I haven't seen it elsewhere: 


[- 

Chose p' so p' = 1 mod 4. Thus p = 3 mod 8, and (2/p) = -1 (ie 2 is a QNR 
mod p). 

Before encryption prepend the bits 001 to the plaintext, test for QR: if it 
is QR then pass on to the encrypter, if it is NQR then shift left (multiply 
by two) before passing it on. 

2 is NQR, and any NQR x any NQR = a QR - so all the blocks sent to the 
encrypter are QRs. 

After decryption, shift right if the second bit of the block is set. Discard 
the first 3 bits.

I Love U (To MY CinderElla)

I love you

like the night loves day
like the dark miss the light
like sand to the water
like nails continue to grow
although always you cut

I love you
sincerely candle on fire
a valley on the mountain would
as calm as a lake in the sky
missed a star on the day
of the heart that you hold
because no registration for the universe
heart that can be as high as you reach
sky-high because no
deep heart can you dive
not as deep as the ocean

I love you
as arrows pointing in my face

pain will rip my pride

to read my Love Story this

IF You Know (an insomniac dreams)

occasional night without the moon appear ...
add to the quietness of the silence ...
left heaven to be abused ..

but never sleep without a dream ...
through the eyes of a vain ..
who continue to come, while dancing the song of lonely ...

I'll never know ..
when he came to me ..
through the river and the hill of soul ...
and I also never knew ...
when she went ...
carry the dream of expensive ...
or also I never knew ...
when she flew ...
carried by the wind ... the wind ... and the male beetles

Surabaya,
dawn, October 2007

ECC Cryptography

elliptic curves cryptosystem or shortened by the ECC, is one of the asymmetric cryptographic system that uses the discrete logarithm problem (the discrete logarithm problem). Structure of elliptic curves are used as mathematical operations group to establish a process of encryption and description

In 1985, Neil Koblitz and Victor Miller independently introducing Elliptic Curves Cryptosystem - ECC which uses the discrete logarithm problem at the points elliptic curve called ECDLP (Elliptic Curves Discrete Logarithm Problem). This Criptosystem ellipse curve can be used in any purposes such as:
• Scheme encryption (ElGamal ECC)
• Digital Signature (ECDSA - Elliptic Curves Digital Signature)
• key exchange protocol (Diffie Hellman ECC)

Elliptic Curves Cryptosystem using discrete logarithm problem in elliptic curve using elliptic curve groups. Structure of elliptic curves are used as mathematical operations group to establish a process of encryption and description. This method causes difficulties to calculate k given Q and P, where Q = k P.

for example calculate the ECC, awaiting the next blog :)

Analyzing in Text Mining

Text Mining is Mine the data in the form of text. Source of data is usually derived from the documents. The goal is to find words that can represent what is in the document so that it can be inter-connectedness analysis of documents

phase of text mining are:
Tokenism
Filtering
Stemming
Tagging
Analyzing

what is Analyzing ?
Finding how much connection between the words between documents
Term Frequency-Inversed Document Frequency (TF-IDF) is the simplest algorithm is usually used for scoring

the process of TF-IDF

(Laylat al-Qadr) ليلة القدر

night a thousand months ...

beautiful night
if You promise me Your love
greatest night
if You give Your heart
because my heart and my love
entirely for You, my Love
Sincerely to You, my Heart
entirely for You, O God

tonight and other nights, I'm Yours

History of Cryptography

Cryptography has been used about 40 centuries ago by the people Egypt to send a message to the troops who were on the battlefield and to the message is not readable by the enemy, although the messenger captured by the enemy. Around 400 BC, cryptography was used by the Spartans in the form of a piece of papyrus or parchment covered with a wooden rod. In ancient Roman times, when Julius Caesar wanted to send a message secret to a general on the battlefield. Such messages should be sent by a soldier, but because it contains a secret message, Julius Caesar did not want to open the message in the middle of the road. Here Julius Caesar thinking about how to handle it is to randomize the contents of the message into a message that can not be understood by anyone but can only be Generals understood by all. Of the General had been notified earlier how to read the random messages, having learned key. In the second world war, German enigma machine or also called the rotor machine used by Hitler to send a message to troops on the battlefield. Germans really believe that the message is encrypted use can not be solved enigma.
But the assumption was wrong, after years of study and the allies had cracked the codes it. After the Germans know that the enigma can be solved, then the enigma has experienced several changes. German Enigma used to encrypt a message that has the possibility to be able 15'1018
decrypt the message. some historians believe that the end of World War II due to the Enigma encryption techniques solved.
The development of computer and communication systems in the 60's impact on the demand of certain parties as a means to protect information in digital form and to provide services security. Starting from Feistel of IBM's business in the early 70s and achieving
\ peak in 1977 with the appointment of DES (Data Encryption Standard) as a federal information processing standards of the United States to encrypt information that is not yet classified. DES is a cryptographic mechanism The most known throughout history. The most surprising development in the history of cryptography occurred in 1976 when Diffiel and Hellman published "New Directions in Cryptography". This paper introduces the revolutionary concept of public key cryptography, and also provides a new method for key exchange, security is based on
power discrete logarithm problem. although, Diffiel and Hellman not have practical realization of the idea of public key encryption that time, the idea is very clear and foster a broad interest in the cryptographic community. In 1978 Riv est, Shamir and Adleman discovered the design of public key encryption is now called RSA. Draft RSA factoring problem, based on hard numbers,

and reactivate efforts to find a more efficient method for factoring. 80 years of vast increases in these areas, the RSA system is still safe. Another system is the design of public key found by Taher ElGamal in 1985. This design based on discrete logarithm problem. One of the important contribution of public-key cryptography is a sign digital signatures. In 1991 the first international standard for digital signatures adopted. This standard is based on RSA public key design. In 1994 United States government adopted the Digital Signature Standard, a cryptographic mechanisms based on the ElGamal algorithm.

Crypto Graphia

Cryptography (cryptography) comes from the Greek, composed of two tribes word of "crypto" and "Graphia". "Crypto" means hidden, while "Graphia" means writing. Cryptography is the study of mathematical techniques related to information security aspects, such as data confidentiality, validity of data, data integrity, and authentication data (Menezes, Oorschot and
Van stone, 1996). But not all aspects of information security can be resolved with cryptography. Cryptography can also be defined as the science or art to message security guard. When a message is sent from one place to others, the content of these messages may be intercepted by other parties who are not entitled to know the contents of the message. To keep the message, the message can be converted into a code that can not be understood by other parties.
Encryption is an encryption process to change a codes (messages) from which can be understood (plaintext) into a code that is not understandable (ciphertext). Whereas the reverse process to convert ciphertext be called plaintext decryption. The process of encryption and decryption mechanisms and require a certain key. Cryptanalysis (cryptanalysis) is the opposite of cryptography, which is a science to solve the cryptographic mechanisms in a way to get the key from ciphertext used to get plaintext. Cryptology (cryptology) is a science that includes cryptography and cryptanalysis.
There are four fundamental goals of cryptography is also an aspect security of information, namely

1. 1. Confidentiality, are aspects related to the maintenance of information content from anyone except those with authority or a secret key to open the encrypted information.
2. 2. Data integrity, are aspects related to the preservation of the data changes illegally. To maintain the integrity of data, the system must have the ability to detect data manipulation by the parties is not entitled, such as insertion, deletion, and substitutedother data into actual data.
3. 3. Authentication, are aspects related to identification or recognition, both for inclusion and the information system itself. Two parties communicate with each other to introduce themselves to each other. The information submitted must be authenticated authenticity, data content, time delivery, and others.
4. 4. Non-repudiation (denial rejected), is an attempt to prevent the denial by sending a sending information, or should be able to prove that a message from someone, when he denied sending such information. (Menezes, Oorschot and Vanstone, 1996).

Encryption PGP (Pretty Good Privacy)

BASIC THEORY



" PGP" (Pretty Good Privacy) is a type of encryption used for encrypting email. created by Phil Zimmerman . Cryptography is best to use. The software also has some integrated one program, also available in the Linux Operating System environments and Windows. Actually, it's free but there are versions that must be paid.
When you use "PGP" you have to have the data in binary form to be sent. So for email delivery at only design in the form of text. "PGP" also makes an encrypted message in the form of a segment if the file is too large.
Working principle of this algorithm "PGP" is when we apply this algorithm to send a message to our friends, "PGP" keys to make 2 pieces of public key and private key (Example Bob And Alice) and Bob and Alice will exchange their public keys.
When Alice sends Bob an email to the email will be encrypted with Bob's public key and Bob's Private Key, then the email will be sent through the network. If BOB wants to read the email then Bob must have a public key and the Allice key Private own.

dream season

dream season


do not ever express hatred
although the heart would not
because I did not know
since when I love you

let dreams fly
with your shadow
if your body is no longer independent

because the boat display was
cross a ocean of love
and is now anchored in your heart
I did not know why the wave
did not take me sailing again

love is not a honey
but love is the spirit of things
believe me, this season is still beautiful
and I'll stay until flamboyant
must fall, and I imagine
you pick it up .... with a smile
and your beautiful eyes say
"This is my love ......"

The Caesar's Cryptography

Caesar substitution:
Cryptography has been known since Roman times. Was a great king of the Romans at that time whose name was Julius Caesar who introduced the first cryptographic techniques. He used it to hide a secret letter he would send. If the couriers were arrested and the letter fell into the hands of the enemy then the Mush still can not get any information even managed to get a physical letter. Caesar cryptography technique is actually simple, namely by replacing each letter with another letter in the alphabet with the previous agreement. So Cesar and the recipients have made an agreement with a table - tables alphabetically between the original letter by letter instead. Here is an example of cryptographic Caesar.

Example, alphabetical table appointments as follows:

If you want to send a C-section the phrase: "WAR" then the contents of the letter is "DZI". While recipients will return to match sentences in the letter in the table and translated back so he could read the same sentence with what is going to be sent Caesar. While others who do not have the above table can not be read, so that security letter awake. It was said that Caesar's love letter to Cleopatra also uses cryptography so that it can not be known by the senate - the Roman senate who did not like his relationship with Cleopatra.

Cryptography techniques above Caesar substitution technique is also called a cesarean (Substitution Caesar) or substitution techniques. Cryptographic system is to survive long enough, but eventually can be solved. The simplicity of the encoding techniques into the basic technique of substitution is weakness. Enough with the technique Brute Force Attack, or even with just the trial error cryptographic encryption can be solved. By simply knowing what the letters out and then a lot of analysis. For example in the Indonesian language the letter 'A' appears at most, so if the letter is the letter 'Z' appears at most, it can be concluded that the letter 'Z' is a substitute letter 'A'. Once on the next to get a clear information.

What is Cryptography?

Cryptography is the art of encoding information by using specific techniques with the aim of such information can only be known and read by the right side. Cryptography is not merely technical, but also an art. This is because an attempt to break the password is also directly proportional to the effort encrypting, or even more. In its development so that any attacker (person who wants to break the cryptographic code) which called "cryptanalysis" and the cryptographers (principals cryptography) is always locked on each others creativity to each technique.

But the science of cryptography can not be separated from the engineering sciences. Particularly modern cryptography which relies heavily on mathematics. In contrast to the more classical cryptography technique modification of existing data in order not to be recognized. In this book we will be much talk about discrete mathematics which became a mainstay of "ElGamal" cryptography.

Actually there is science in addition to other cryptography to encrypt data that is stenography, which is a data encryption technique with increasing data - other data or abbreviate the data with a specific pattern. Examples of the shorthand is Digital watermarking. Explanation of stenography will be discussed in the chapter on stenography.

Cryptography itself divided by the time period Type 2, namely:

1. Classical cryptography.
2. Modern cryptography.

Meanwhile, if divided by type of cryptographic keys are used, then the cryptography is also divided by 2 is:

1) Symmetric Cryptography
2) asymmetric Cryptography

Cryptography is also divided based on 2 sharing data will be processed, namely:

1. Cryptography Chipper Block
2. Cryptography Stream

مرحبا بكم في رمضان

مرحبا بكم في رمضان

welcome Ramadan. months full forgiveness and mercy. Love that always meet the longing of the soul unto God. this month I will submit everything to you my love. Not because of heaven or hell, but because you love ....

in this August 17 date 64 years ago, Ramadan is a silent witness the independence of Indonesia. Ramadan 5 years ago I can still see the girl that I love, and June 5 24 years ago, my birth date is

Ramadan is always so special for me

Filter Stop List

stop list is a text data that is contained in a particular list. Stop list is a list of words omitted in the text mining. Stop list is an example subject, pronoun, conjunction, etc..

Data in the stop list is not needed in search of information and knowledge to the text data. example a sentence "I love you", the world "I" and "you" do not have meaning in the text because knowledge is certainly the word love. I said you and data including the stop list.

in a system of text data mining more detail a list it will stop the better. this is because the process of stemming the words, Tagging, and keyword search text data will be shorter. effectiveness in time and memory to be the main goal of making stop list.

Stemming the sentences

"Stemming the sentence" is a process of splitting the sentence into words - the words. In programming languages are usually known by the name "tokenism". Why the sentence should be parsed into words? this process so that the introduction of the text is running with the pitch and fast measure. With the introduction of a data per text in the word can be ascertained that there is no data that is not in the process.

problems that arise is how the word back in the Indonesian language. Of course there must be reprocess for word - the word is back. Or can only, be a re-word a word itself or may be double counted. That's up to the case faced by a system analyst.

What is "Pre processing" ?

"Preprocessed" is a data cleaning process to be more easily processed by the system. Preprocessed is useful in order to extract the data before and taken his knowledge or keyword does not already have dirty data or data that are not needed. Example of dirty data such as:

• Digit
• Punctuation
• Bullets

Based on the research I do, numbers, punctuation marks, and bullets do not have a significant influence on a text data. This is because data in the text will eventually be in the ranking while the data is dirty data can not stand on its own.

Because it is the numbers, punctuation marks, and bullets need to be erased before the process of text mining that others do.

this is the scheme of prepossessing

The Text Mining

Text mining is a system to mine data as text. The mine here in the analogy can be like someone who is a gold mine. When the mine equipment was then a lot of clay, but we separated them and find where the existence of the gold is.

Same as text mining, we search for knowledge or important data from the data that a lot of text. The resulting data is a keyword or data that indicates the content of text data before.

Here is a text mining scheme:

to more clearly waiting next article

Searching Verse - Ayat Al - Qur'an Content Based on the belief Problems In Using Text Mining (My Final Project Prposal)

Internet world is very much sought by the community. Many of them are looking for solutions, tutorials, discussion, or browse through the discussion on the Internet. One is looking for the solution of the problem belief.

Verse - verse in Al - Qur'an is not organized based on a problem, so does the scatter, so it takes a long time to search verses - verses that are required for problem-solving faith.

So with the end of this project will help to find a verse reference and translation Al - Qur'an problems in belief, and are easily accessible because of web-based so it can be used by anyone

Keywords: Internet, Text Mining, Al - Qur'an, belief

Background authors take the title of this final project is difficulty implementing the Al-Qur'an in life - especially in the day by solving some of the people, as the form of Al-Qur 'an that conventional hard to learn.

Verse - verse in "Al - Qur'an" is not organized based on a problem, so does the scatter, so it takes a long time to search verses - verses that are required for problem-solving faith.
Search process clause - paragraph conventional "Al - Qur'an" way or with the Al - Qur'an during which digital is on the Internet (eg www. QuranDigital.Com-Al) is not enough to help, if the results we want is a paragraph -- paragraph in accordance with the particular problems that we face. With such a system is required to identify, find, and group problem diinputkan by the user. So that the system can display the verse - verse "Al - Qur'an" as a reference and solutions.

With the above problems, then you can use a process of introducing the text in a Text Mining. With the process so that problems in the user input performed with several methods such as parsing, stemming, and morphing To be able to recognize problems.
By the end of this project is expected to help find a verse reference and translation "Al - Qur'an" problems in belief, and are easily accessible because of web-based so it can be used by anyone.

Authors interested in writing and discuss the text mining al - Qur'an. Especially in extracting information about the problem of faith in verse - verse it. With the goal of producing a web application that can:

1. 1. Search for verse - verse al qur 'an issue of translation and belief
2. 2. Providing solutions to the problems of displaying text - verse and translated it.

The problem was that in the end of this project are:

• How to search for keywords from the problems that have?
• How can differentiate the problem, including a belief or not?
• How to related a problem with the belief paragraph - paragraph "Al - Qur'an" and translated?

TEXT MINING
text mining is the process of mine text data with a data source is usually from the document and find the goal is the word - a word that represents a document so that it can be done in the analysis relationship document [1] ..
Text data will be processed into numeric data that can be process further. So in terms of text mining is the data pre processing - that is the precursor that is applied to the text data that aims to generate numeric data [3].


On pre prosesing have conducted several phases, namely [4]:

• Removal and markup format document that is used if a text is not pure then this step is taken. Because the text document that usually we see a non-text formats such as html, pdf or in the form of a word. Format this format requires that a text has additional elements to be able to generate the view that our friendly eyes. Information is omitted because they do not need and do not reflect the contents of a text document
• Remove punctuation punctuation and numbers is also considered not important, because it happens in the research that I do not see the relevance words, sentences or the like, so the word is considered independently.
• Changing from capital letters to all lowercase.
• Parsing and Stemming. decomposition into the form of single words and words into the form of the establishment of the foundation, so that words that have a basic form of words will be the same.
• Weighting -> Starting with the calculation of the number of words in each document, which will then be calculated using the scheme weighting process desired.

Science belief according to Al - Digital Koran is a faith and confidence of Allah, which are grouped in a peaceful faith that we know [5] [6] [9]:

1. Faith in God

2. Faith to Angel of God

3. The faith of Scripture

4. The faith of the Messenger of Allah

5. Faith to the Day of Resurrection

6. The faith of destiny

Here is a system architecture design project end. Where users do request to the web server, web server and computing to explore with the authentication keyword database. Then the web server to provide the results to the user.

Process on the end of this project are:

1. The process is there is a prepossessing method to remove the punctuation mark, number, symbol, mark up, and make all the words with the uniform makes them all small letters.
2. Stemming the method is to split the sentence into words - words that stand alone. Because the word in the text mining in the sentence has no relevance.
3. Stemming the words of this process is cut so that the leading particle and the word - a word only in the form of basic words. So weighting valid.
4. Weighting or group weighting process word - a word basis.
5. Search for keyword keyword is the word - a word which is more than 2 and is a keyword in the belief

Conclusion

Based on the results of experiments and analysis carried out in the Project End this can be concluded that:

1) The system has been created as able to meet the needs of search applications verse - verse of the Holy "Qur'an"-related problems by using the belief Text Mining.
2) All the keywords that can be identified particle all except the word "kingdom" which is the "king".
3) This system does not save all the data "Al - Qur'an" on a problem, but taken at least 70% of the "Al - Qur'an". Data "Al - Qur'an" is considered to be taken to represent the other.


2. Advice

Here are some suggestions for the development of the system in the future, based on the results of the design, implementation, and testing that was done.:
1) Complete data paragraph "Al - Qur'an", of course, must at the same time with a larger database from "MYSQL".
2) Complete the data keyword belief problems
3) improve the stemming algorithm, that is the case in the word "kingdom". With:
a. First check in the database, including whether or not the basic word. If you are including the words do not have the basic process through stemming.
b. Perfect combination of particle algorithm.
4) The making of the application form of "WAP" or desktop applications, so that the web service can be accessed by the application of the various platforms.
5) The making of the feature entry words and basic word of particle with administrative authentication credentials.

Just Joke

a day, john was near death. with a pain he said to his wife, Alice.

John: My dear, after I die I want you to marry Bob. I will be quiet in heaven if you become his wife.

Alice: Bob enemies when you are young, why do you want me married to Bob?

John: Thus I want him to feel that I Suffering natural for this since I married You.

Ensuring Security Cryptography

In this world there are some parties who want to take information from chipertext already in cryptography. party called kriptanalis.

Kriptoanalisis also be defined as art or science to solve ciphertext become plaintexts using the midst security a cryptography system. This makes Kriptoanalisis labeled as illegal ways to translate ciphertext. Based on the activities of attackers, the attack that occurred can be divided into two types, namely:

a) passive attacks, where attack is attacker only monitors the channel communication. Passive attacker only threaten confidentiality of data.

b) active attacks, where attack is
attacker trying to remove, add, or in a way that another change in the transmission path of communication. Active attacker will threaten data integrity and authentication, and confidentiality.


Types of Seizures
There are several types of attacks that can be done by kriptoanalis, with the assumption that kriptoanalis had cryptography algorithm used in the system that will be attacked, namely:

1. Ciphertext Only Attack
'Kriptoanalis' only have a few ciphertext a result of tapping. But he does not know the key and the plaintext. Employment 'kriptoanalis' is seeking to obtain the decryption key the plaintext.

2. Known Plaintext Attack
Kriptoanalis successfully obtain discount
the plaintext and a full the chipertext, but he believes that both are interconnected. For example, the snippet plaintext which is believed to be a letter, because there is the phrase "respect us." 'Kriptoanalis' then try to match the chipertext that have meaning "respect us." Next task is to find a little of the decryption key information that he had it.

3. Candy Plaintext Attack
"Kriptoanalis" not only know a plaintext and the chipertext as in the case 2 above, but also free to choose some plaintext considered in accordance with a certain part of ciphertext. "Kriptoanalis" next task is to a key of guess.

4. Adaptive Candy Plaintext Attack. This attack is a special case of third type of attack mentioned above. "Kriptoanalis" not can only select a the plaintext would be encrypted, but can also modify choice based on the results of previous encryption. In Candy the plaintext attack, it may only can select a block for large plainteks encrypted, while he is on the attack can block plaintext choose a smaller and then select the other based on the results previously.

5. Candy Ciphertext Attack
"Kriptoanalis" can choose which ciphertext different decryption and to have access against plaintext encrypted. As example, "kriptoanalis" have access to the box
electronic process that can perform decryption automatically. Employment is "kriptoanalis" find the decryption key.

6. Candy Text
Candy is a combination of plaintext attack Candy and ciphertext attack. Here "kriptoanalis" already know the encryption algorithm ciphertext used and that will be read. "Kriptoanalis" can also select the plaintext would be cipherteks encrypted with spouse raised with a particular secret key.

Conditions that ensure security algorithms

There are 3 conditions that, when fulfilled by the algorithm cryptography, it will be able to guarantee security confidential communication made, namely:

1. If the cost to attack or penetrate cryptography algorithms that are used more than the price information will be obtained from results of these attacks. For example, the required computer system is worth 1 billion to penetrate algorithm that is used to protect information is worth 500 million.

2. When the time needed to penetrate algorithm is longer than the validation who wish to obtain information. For example, the time to penetrate a credit card is 1 years, whereas before the 1 year credit card is no longer valid.

3. When cipherteks produced by a cryptography algorithm less than cipherteks required to penetrate algorithm it. For example, of 1000 bits is required cipherteks to hit the key that is used on an algorithm, while the data resulting from the size of the encryption process is less of 1000 bits.

About Taher El Gamal (wikipedia)

Dr. Taher Elgamal

(born 18 August 1955) is an Egyptian cryptographer. Elgamal is sometimes written as El Gamal or ElGamal, but Elgamal is now preferred. In 1985, Elgamal published a paper titled A Public key Cryptosystem and A Signature Scheme based on discrete Logarithms in which he proposed the design of the ElGamal discrete log cryptosystem and of the ElGamal signature scheme. The latter scheme became the basis for Digital Signature Algorithm (DSA) adopted by National Institute of Standards and Technology (NIST) as the Digital Signature Standard (DSS). He also participated in the 'SET' credit card payment protocol, plus a number of Internet payment schemes.

Elgamal has gained a Bachelor of Science degree from Cairo University, and Masters and Doctorate degrees in Computer Science from Stanford University. He served as chief scientist at Netscape Communications from 1995 to 1998 where he was a driving force behind SSL. He also was the director of engineering at RSA SecuritySecurify in 1998 and becoming their CEO. When Securify was acquired by Kroll-O'Gara[1], a company providing Independent IT Controls measurement and software verification at the binary level. In October 2006 he joined Tumbleweed Communications [2] in a capacity of a Chief Technology Officer. Tumbleweed was acquired in 2008 by Axway Inc. He is an advisor to Onset Ventures, glenbrook partners, PGP corporation, Arcot Systems, Finjan, Facetime and serves as Chief Security Officer of Axway, Inc. Inc. before founding he became the president of its information security group. In 2008, Securify was acquired by Secure Computing and is now part of McAfee. In addition, Elgamal sits on the board of Vindicia, a company which provides online payment services as well as the Advisory Board of SignaCert, Inc.

Example of El Gamal Criptography in Number

Picture above is an example of numerical calculation analogy ElGamal. Clark Kent was originally the public key (y), after he chose a private key is (x). Count y can be read in addition chaining post in this blog. after that Clark tells Lex Luthor key public.

Lex Luthor will send a character 'A' to Clark. Knowing Clark's public key and private key without knowing the property of Clark, he calculates chiperteks (a, b). ASCII characters with a code and b is sent to Clark. Clark chiperteks receive it. ago he was doing decryption by using a and b. plainteks that is' A ', the same as you want to send Lex Luthor

Number Of ElGamal

If all the prime factors of p - 1 are relatively
small, lots of cryptographic attacks are possible. Generally, primes p such that p-1 has a big prime
factor are much better.









Note: k; r can be computed before the message is seen. In addition, you need a new k and r
every time you sign a message. Otherwise, it will not be secure.







Digital Signature Algorithm (DSA)

Addition Chaining or Divide and Conquer for ElGamal Programing

Problems in the Calculations exponential and modulo in 'El Gamal' can be done using the manual counting or a calculator, but if the code is calculated in the program will generate a value of 0. this is because there is no data type in programming resource that can accommodate the data before these modulus. So to solve this problem some authors reduce the formula to calculate a and y.

vw mod p = [( v mod p )( w mod p )] mod p
example :



Method above in mathematics discreet technique called divide and conquer. Referred to as addition chaining technique because the results was carried out together with direct multiplication modulo operation. With this technique, the results will not reach a large number.

Besides the problem of y and a, the value of b also has a similar problem. Even in the calculation of b values before the integer modulus greater. This is because in addition to exponensial with a large number but also multiplied by the value of plain text blocks to mj. With divide and conquer method is also the formula b can be measured down

revealed to be:


From the equation above can be concluded that the value of mj is no need to be a factor during the process y^k mod p is calculated. Fair value multiplied later after y ^ k mod p is established, and then the new modulus with p more

ASCII TABLE FOR EMAIL APLICATION USE ELGAMAL KRIPTOGRAPHY

{“32”,” ”} 0
{“33”,”!”} 1
{“34”,”””} 2
{“35”,”#”} 3
{“36”,”$”} 4
{“37”,”%”} 5
{“38”,”&”} 6
{“39”,”’”} 7
{“40”,”(”} 8
{“41”,”)”} 9
{“42”,”*”} 10
{“43”,”+”} 11
{“44”,”,”} 12
{“45”,”-”} 13
{“46”,”.”} 14
{“47”,”/”} 15
{“48”,”0”} 16
{“49”,”1”} 17
{“50”,”2”} 18
{“51”,”3”} 19
{“52”,”4”} 20
{“53”,”5”} 21
{“54”,”6”} 22
{“55”,”7”} 23
{“56”,”8”} 24
{“57”,”9”} 25
{“58”,”:”} 26
{“59”,”;”} 27
{“60”,”<”} 28 {“61”,”=”} 29 {“62”,”>”} 30
{“63”,”?”} 31
{“64”,”@”} 32
{“65”,”A”} 33
{“66”,”B”} 34
{“67”,”C”} 35
{“68”,”D”} 36
{“69”,”E”} 37
{“70”,”F”} 38
{“71”,”G”} 39
{“72”,”H”} 40
{“73”,”I”} 41
{“74”,”J”} 42
{“75”,”K”} 43
{“76”,”L”} 44
{“77”,”M”} 45
{“78”,”N”} 46
{“79”,”O”} 47
{“80”,”P”} 48
{“81”,”Q”} 49
{“82”,”R”} 50
{“83”,”S”} 51
{“84”,”T”} 52
{“85”,”U”} 53
{“86”,”V”} 54
{“87”,”W”} 55
{“88”,”X”} 56
{“89”,”Y”} 57
{“90”,”Z”} 58
{“91”,”[”} 59
{“92”,”\”} 60
{“93”,”]”} 61
{“94”,”^”} 62
{“95”,”_”} 63
{“96”,”`”} 64
{“97”,”a”} 65
{“98”,”b”} 66
{“99”,”c”} 67
{“100”,”d”} 68
{“101”,”e”} 69
{“102”,”f”} 70
{“103”,”g”} 71
{“104”,”h”} 72
{“105”,”i”} 73
{“106”,”j”} 74
{“107”,”k”} 75
{“108”,”l”} 76
{“109”,”m”} 77
{“110”,”n”} 78
{“111”,”o”} 79
{“112”,”p”} 80
{“113”,”q”} 81
{“114”,”r”} 82
{“115”,”s”} 83
{“116”,”t”} 84
{“117”,”u”} 85
{“118”,”v”} 86
{“119”,”w”} 87
{“120”,”x”} 88
{“121”,”y”} 89
{“122”,”z”} 90
{“123”,”{”} 91
{“124”,”|”} 92
{“125”,”}”} 93
{“126”,”~”} 94
{“127”,”DEL”} 95
{“128”,”Ç”} 96
{“129”,”ü”} 97
{“130”,”é”} 98
{“131”,”â”} 99
{“132”,”ä”} 100
{“133”,”à”} 101
{“134”,”å”} 102
{“135”,”ç”} 103
{“136”,”ê”} 104
{“137”,”ë”} 105
{“138”,”è”} 106
{“139”,”ї”} 107
{“140”,”î”} 108
{“141”,”ì”} 109
{“142”,”Ä”} 110
{“143”,”Å”} 111
{“144”,”É”} 112
{“145”,”æ”} 113
{“146”,”Æ”} 114
{“147”,”ô”} 115
{“148”,”ö”} 116
{“149”,”ò”} 117
{“150”,”û”} 118
{“151”,”ù”} 119
{“152”,”_”} 120
{“153”,”Ö”} 121
{“154”,”Ü”} 122
{“155”,”blank”} 123
{“156”,”£”} 124
{“157”,”¥”} 125
{“158”,”_”} 126
{“159”,”ƒ”} 127
{“160”,”á”} 128
{“161”,”í”} 129
{“162”,”ó”} 130
{“163”,”ú”} 131
{“164”,”ñ”} 132
{“165”,”Ñ”} 133
{“166”,”ª”} 134
{“167”,”°”} 135
{“168”,”¿”} 136
{“169”,”_”} 137
{“170”,”¬”} 138
{“171”,”½”} 139
{“172”,”¼”} 140
{“173”,”¡”} 141
{“174”,”«”} 142
{“175”,”»”} 143
{“176”,”░”} 144
{“177”,”▒”} 145
{“178”,”▓”} 146
{“179”,”│”} 147
{“180”,”┤”} 148
{“181”,”╡”} 149
{“182”,”╢”} 150
{“183”,”╖”} 151
{“184”,”╕”} 152
{“185”,”╣”} 153
{“186”,”║”} 154
{“187”,”╗”} 155
{“188”,”╝”} 156
{“189”,”╜”} 157
{“190”,”╛”} 158
{“191”,”┐”} 159
{“192”,”└”} 160
{“193”,”┴”} 161
{“194”,”┬”} 162
{“195”,”├”} 163
{“196”,”─”} 164
{“197”,”┼”} 165
{“198”,”╞”} 166
{“199”,”╟”} 167
{“200”,”╚”} 168
{“201”,”╔”} 169
{“202”,”╩”} 170
{“203”,”╦”} 171
{“204”,”╠”} 172
{“205”,”═”} 173
{“206”,”╬”} 174
{“207”,”╧”} 175
{“208”,”╨”} 176
{“209”,”╤”} 177
{“210”,”╥”} 178
{“211”,”╙”} 179
{“212”,”╘”} 180
{“213”,”╒”} 181
{“214”,”╓”} 182
{“215”,”╫”} 183
{“216”,”╪”} 184
{“217”,”┘”} 185
{“218”,”┌”} 186
{“219”,”█”} 187
{“220”,”▄”} 188
{“221”,”▌”} 189
{“222”,”▐”} 190
{“223”,”▀”} 191
{“224”,”α”} 192
{“225”,”β”} 193
{“226”,”Γ”} 194
{“227”,”π”} 195
{“228”,”∑”} 196
{“229”,”σ”} 197
{“230”,”μ”} 198
{“231”,”τ”} 199
{“232”,”Φ”} 200
{“233”,”Θ”} 201
{“234”,”Ω”} 202
{“235”,”δ”} 203
{“236”,”∞”} 204
{“237”,”ф”} 205
{“238”,”ε”} 206
{“239”,”∩”} 207
{“240”,”≡”} 208
{“241”,”±”} 209
{“242”,”≥”} 210
{“243”,”≤”} 211
{“244”,”⌠”} 212
{“245”,”⌡”} 213
{“246”,”÷”} 214
{“247”,”≈”} 215
{“248”,”°”} 216
{“249”,”.”} 217
{“250”,”.”} 218
{“251”,”√”} 219
{“252”,”_”} 220
{“253”,”²”} 221
{“254”,”■”} 222


Description:
( "Xxxx", "Y") = aaa
Xxx = ASCII code beginning
Y = the characters in the code
Aaa = new code because the data migration code 0 - 31 not used
Number of characters = 223 is the same as the p value is 223 (prime and range data)

Respected, or in Fear ?

Some people valued because people fear him, but people have appreciated that because other people really respect him. What is the difference between respect and fear? if respect because they fear a later time when we are weak then that person will no longer fear us. However, if you appreciated the honor because in any situation, people will still appreciate.

I am confused, what I appreciated because other people fear to me, or because of the respect? or may be more severe than the "required"?

The El Gamal Cryptosystem

We have seen that the security of the RSA Cryptosystem is related to the difficulty of
factoring large numbers. It is possible to construct Cryptosystems based on other difficult
number-theoretic problems. We now consider the El Gamal Cryptosystem, named after its
inventor, 'Taher El Gamal', which is based on the difficulty of a problem called the \discrete
logarithm."

algorithm ElGamal public key cryptography

P { margin-bottom: 0.08in } -Our lives at this time influenced by cryptography. From transactions in the ATM machine, hold a conversation via telephone, Internet access, until the missile control using cryptography. Once the importance of cryptography for security information (Information Security), so that when talking about security problems associated with the use of computer, so can not be separated from the cryptography.

One of the algorithms used for encryption and discussed in this article are ElGamal algorithm. This algorithm emphasizes the problems mathematics algorithms. Problems with the ElGamal encryption chipertext results will be very difficult in kriptanalis.

The problems raised in this article are:

1. How to generate random numbers (prime and not prime) to be the key cryptography in the system?
2. How to publish public key and private key to hide?
3. How do I calculate a exponent operation that produces an integer that is very large so that can not be saved by any type of data in a resource program (JAVA)?
4. How do I calculate the modulo operation of an integer is very large?
5. How do I calculate the inversion modulo operation of an integer is very large?
6. How to plain text character conversion chiper text or otherwise using the ASCII table, where the maximum number of ASCII characters must be a prime?

Problems in discrite Algorithm El Gamal is: if p is a prime and g and y is any integer. Find x so that g ^ x ≡ y (mod p). Scale used in the El Gamal is:
1. The prime p (not secret)
2. Random number, g (g

Elgamal algorithm algorithm is one of the public-key cryptography is created by Taher ElGamal in 1984. In the algorithm is generally used for digital signatures, but then modified so that it can also be used for encryption and description.

Encryption process is as follows:

• Encryption

1. Plainteks organized into blocks of m1, m2, ..., so that each block represents the value in the range 0 to p - 1.
2. Select a random number k, which in this case 0
3. Each block is encrypted with the formula m
4. a = g^k mod p (1)
5. b = y^km mod p (2)
6. Pair a and b are cipherteks to block the message m. Thus, the size ciphertext twice its size plainteks.

• Decryption

1. For a and b mendekripsi use a secret key, x, and m plainteks be back with the equality
   m = b / a^x mod p (3)
   mathematics from the equation above can be plainteks that can be returned with the pair a and b

Making a System
Here is a flowchart used in Agoritma ElGamal:

The first prime number p randomly resurrected. Numbers p Range data is used as a reference for plainteks and chiper text. Eg reference to the ASCII code 0 - 256 then the p value is 257.
After that raised random value g and x. X is the value of private key can be raised up so the user wishes and do not have to be random. Terms of generation g and the value of x is:

After the countdown y (public key) to call a function to calculate the y value of the shipment paremeter g, x, and p. After we made the key y g, y, p as a public key and private key as x.

After determining the key encryption process is complete then the message begins with a special encryption function call with parameter m post plain text and key - public key.

After the encryption then email is sent to the destination email. Chiper text size 2X plain text. Once the recipient receives the email in the text chiper decryption with the decryption function with parameters that are sent chiper text. The process of decryption will be done by using the private key of the recipient email (x).

Operation in the a and y is the same value pangkatnya just different. In the a, g dipangkatkan with k while the y, g dipangkatkan with x.

Encryption algorithm from the above looks simple. However, there are complex issues that matter for inclusion in the program code. This is because the algorithm ElGamal operation perpangkatan and modulo the number that large. For example eg in the y and a:
If p = 223 g = 13 x = 131 and k = 127

Above problems can be overcome with the addition of the concept of chaining or divide and conquer

Decryption
Decryption formula is as follows:

formula derived above need to be counted as regular as if it will result in a decimal value. In fact the value in the ASCII table is always integer. So 1 / (a^x) will be downgraded to

Results obtained in decryption is the same value of mj mj with a value that is sent before encryption

the sender does not need to know the private key of the goal. Simply use the public key issued by the Email recipient. With the mathematics diskrit Chipper results obtained a text which does not contain any information on if taken by the man in the middle. That can perform decryption of the text Chipper only party that has a private key or know the purpose of email.