The Data Inscription Standard Computer Science Essay



Whenever data is exchanged electronically many times the privacy of the data is a required. Encryption is used to restrict unintended recipients from viewing the data, which are deemed confidential and potentially dangerous if made known to irresponsible parties. In other word, encryption is the procedure of transforming plain text data that can be read by anyone to cipher text data that can only be read by someone with a secret decryption key.A message before being changed in any way is called plain text. Plain text messages are converted to ciphertext via some encryption method. An enryption method is called a cryptosystem.

In 1972, the National Bureau of Standards (NBS), a part of the U.S. Department of Commerce, initiated a program to develop standards for the protection of computer data. The Institute for Computer Sciences and Technology (ICST), one of the major operating units of the National Bureau of Standards, had been recently established in response to a 1965 federal law known as the Brooks Act (PL89-306) that required new standards for improving utilization of computers by the federal government. Computer security had been identified by an ICST study as one of the high-priority areas requiring standards if computers were to be effectively used. A set of guidelines and standards were defined by the ICST that were to be developed as resources became available in computer security. The guidelines were to include areas such as physical security, risk management, contingency planning, and security auditing. Guidelines were adequate in areas not requiring interoperability among various computers. Standards were required in areas such as encryption, personal authentication, access control, secure data stor-age, and transmission because they could affect interoperability.

Standards can be divided into different sections: basic, interoperability, interface, and implementation.

1. Basic standards (also called 4'standards of good practice") are used to specify generic functions (services, methods, results) required to achieve a certain set of common goals. Examples include standards for purity of chemicals, contents of food products, and in the computer field, structured programming practices.

2. Interoperability standards specify functions and formats so that data transmitted from one computer can be properly acted on when received by another computer.The implementation (hardware, firmware, software) or structure (integrated, isolated, interfaced layers) need not be specified in interoperability standards, since there is no intent of replacing one implementation or structure within a system with another.

3. Interface standards specify not only the function and format of data crossing the interface, but also include physical, electrical, and logical specifications sufficient to replace one implementation (device, program, component) on either side of the interface with another.

4. Implementation standards not only specify the interfaces, functions, and formats, but also the structure and the method of implementation. These may be necessary to assure that secondary characteristics such as speed, reliability, physical security, etc. also meet certain needs. Such standards are often used to permit component replacement in an overall system.

Services or Applications

The basic DES algorithm can be used for both data encryption and data authentication.

1. Data Encryption: It is easy to see how the DES may be used to encrypt a 64-bit plaintext input to a 64-bit cipher text output, but data are seldom limited to 64 bits. In order to use DES in a variety of cryptographic applications, four modes of operation were developed: electronic codebook (ECB); cipher feedback (CFB); cipher block chaining (CBC); and output feedback (OFB) [26] (Figs. 1-4). Each mode has its advantages and disadvantages. ECB is excellent for encrypting keys; CFB is typically used for encrypting individual characters; and OFB is often used for encrypting satellite communications. Both CBC and CFB can be used to authenticate data. These modes of operation permit the use of DES for interactive terminal to host encryption, crypto-graphic key encryption for automated key management applications, file encryption, mail encryption, satellite data encryption, and other applications. In fact, it is extremely difficult, if not impossible, to find a cryptographic application where the DES cannot be applied.

Figure 1: Electronic codebook (ECB) mode.

Figure2: Cipher block chaining (CBC) mode.

History of encryption

In its earliest form, people have been attempting to conceal certain information that they wanted to keep to their own possession by substituting parts of the information with symbols, numbers and pictures. Ancient Babylonian merchants used intaglio, a piece of flat stone carved into a collage of images and some writing to identify themselves in trading transactions. Using this mechanism, they are producing what today we know as 'digital signature.' The public knew that a particular 'signature' belonged to this trader, but only he had the intaglio to produce that signature.

Of course, technology today has evolved at such rapid pace that the need to protect information grows with the lessening reliability of older encryption techniques. Basic modern encryption is not much different from the ancient civilisations' substitution using symbols. Translation table, lends itself very well in making a piece of data generally unreadable. However computers today are much too advanced that translation table is easily broken and thus no longer viable. Instead encryption today has grown into such specialised field that involve mathematical, non-linear cryptosystem that even a relatively powerful computers take months or even years to break the ciphertext.

The origins of DES go back to the early 1970s. In 1972, after concluding a study on the US government's computer security needs, the US standards body NBS (National Bureau of Standards) - now named NIST (National Institute of Standards and Technology) - identified a need for a government-wide standard for encrypting unclassified, sensitive information.[1] Accordingly, on 15 May 1973, after consulting with the NSA, NBS solicited proposals for a cipher that would meet rigorous design criteria. None of the submissions, however, turned out to be suitable. A second request was issued on 27 August 1974. This time, IBM submitted a candidate which was deemed acceptable - a cipher developed during the period 1973-1974 based on an earlier algorithm, Horst Feistel's Lucifer cipher. The team at IBM involved in cipher design and analysis included Feistel, Walter Tuchman, Don Coppersmith, Alan Konheim, Carl Meyer, Mike Matyas, Roy Adler, Edna Grossman, Bill Notz, Lynn Smith, and Bryant Tuckerman.

NSA's involvement in the design

On 17 March 1975, the proposed DES was published in the Federal Register. Public comments were requested, and in the following year two open workshops were held to discuss the proposed standard. There was some criticism from various parties, including from public-key cryptography pioneers Martin Hellman and Whitfield Diffie, citing a shortened key length and the mysterious "S-boxes" as evidence of improper interference from the NSA. The suspicion was that the algorithm had been covertly weakened by the intelligence agency so that they - but no-one else - could easily read encrypted messages.[2] Alan Konheim (one of the designers of DES) commented, "We sent the S-boxes off to Washington. They came back and were all different."[3] The United States Senate Select Committee on Intelligence reviewed the NSA's actions to determine whether there had been any improper involvement. In the unclassified summary of their findings, published in 1978, the Committee wrote:


However, it also found that


Another member of the DES team, Walter Tuchman, stated "We developed the DES algorithm entirely within IBM using IBMers. The NSA did not dictate a single wire!"[6] In contrast, a declassified NSA book on cryptologic history states:


Some of the suspicions about hidden weaknesses in the S-boxes were allayed in 1990, with the independent discovery and open publication by Eli Biham and Adi Shamir of differential cryptanalysis, a general method for breaking block ciphers. The S-boxes of DES were much more resistant to the attack than if they had been chosen at random, strongly suggesting that IBM knew about the technique in the 1970s. This was indeed the case; in 1994, Don Coppersmith published some of the original design criteria for the S-boxes.[9] According to Steven Levy, IBM Watson researchers discovered differential cryptanalytic attacks in 1974 and were asked by the NSA to keep the technique secret.[10] Coppersmith explains IBM's secrecy decision by saying, "that was because [differential cryptanalysis] can be a very powerful tool, used against many schemes, and there was concern that such information in the public domain could adversely affect national security." Levy quotes Walter Tuchman: "[t]he asked us to stamp all our documents confidential... We actually put a number on each one and locked them up in safes, because they were considered U.S. government classified. They said do it. So I did it". Bruce Schneier observed that "It took the academic community two decades to figure out that the NSA 'tweaks' actually improved the security of DES."

Encryption Now a Days

Industrial espionage among highly competitive businesses often requires that extensive security measures be put into place. And, those who wish to exercise their personal freedom, outside of the oppressive nature of governments, may also wish to encrypt certain information to avoid legalities that entailed possession of such.

With respect to the Internet, there are many types of data and messages that people would want to be kept secret. Now that commercial trading on the Net is a reality, one of the main targets of data encryption is credit card numbers. Other information that could otherwise benefit or educate a group or individual can also be used against such groups or individuals.

Security Problems That Encryption Does Not Solve


â€¢ Principle 1: Encryption Does Not Solve Access Control Problems

â€¢ Principle 2: Encryption Does Not Protect Against a Malicious Database Administrator

â€¢ Principle 3: Encrypting Everything Does Not Make Data Secure

Principle 1: Encryption Does Not Solve Access Control Problems

Most organizations must limit data access to users who must see this data. For example, a human resources system may limit employees to viewing only their own employment records, while allowing managers of employees to see the employment records of subordinates. Human resource specialists may also need to see employee records for multiple employees.




Principle 2: Encryption Does Not Protect Against a Malicious Database Administrator












Principle 3: Encrypting Everything Does Not Make Data Secure






EFS technology makes it so that files encrypted by one user cannot be opened by another user if the latter does not possess appropriate permissions. After encryption is activated, the file remains encrypted in any storage location on the disk, regardless of where it is moved. Encryption is can be used on any files, including executables.

The user with permission to decrypt a file is able to work with the file like with any other, without experiencing any restrictions or difficulties. Meanwhile, other users receive a restricted access notification when they attempt to access the EFS encrypted file.

This approach is definitely very convenient. The user gets the opportunity to reliably and quickly (using standard means) limit access to confidential information for other household members or colleagues who also use the computer.

EFS seems like an all-around winning tool, but this is not the case. Data encrypted using this technology can be entirely lost, for example during operating system reinstallation.

We should remember that the files on disk are encrypted using the FEK (File Encryption Key), which is stored in their attributes. FEK is encrypted using the master key, which in turn is encrypted using the respective keys of the system users with access to the file. The user keys themselves are encrypted with the users' password hashes, and the password hashes use the SYSKEY security feature.

This chain of encryption, according to EFS developers, should reliably protect data, but in practice, as explained below, the protection can be ultimately reduced to the good old login-pass-word combination.

Thanks to this encryption chain, if the password is lost or reset, or if the operating system fails or is reinstalled, it becomes impossible to gain access to the EFS-encrypted files on the drive. In fact, access can be lost irreversibly.

Regular users do not fully understand how EFS works and often pay for it when they lose their data. Microsoft has issued EFS documentation that explains how it works and the main issues that may be encountered when encrypting, but these are difficult for regular users to understand, and few read the documentation before starting to work.

Data Encryption Challenges


â€¢ Encrypting Indexed Data

â€¢ Generating Encryption Keys

â€¢ Transmitting Encryption Keys

â€¢ Storing Encryption Keys

â€¢ Changing Encryption Keys

â€¢ Encrypting Binary Large Objects

Encrypting Indexed Data




â€¢ There are privacy issues associated with overuse of national identity numbers (for example, identity theft).

â€¢ Sometimes national identity numbers can have duplicates, as with U.S. Social Security numbers.

Generating Encryption Keys





Transmitting Encryption Keys


Storing Encryption Keys


The options available to a developer are:

Storing the Encryption Keys in the Database

Storing the Encryption Keys in the Operating System

Users Managing Their Own Encryption Keys

Using Transparent Database Encryption and Table space Encryption

Storing the Encryption Keys in the Database





wrap iname=/mydir/keymanage.sql





SYS.DBMS_DDL.CREATE_WRAPPED (function_returning_PLSQL_code());......




The strengths of this approach are:

â€¢ Users who have direct table access cannot see the sensitive data unencrypted, nor can they retrieve the keys to decrypt the data.


â€¢ The data transformation algorithm is hidden from casual snooping by wrapping the procedure, which obfuscates the procedure code.




Storing the Encryption Keys in the Operating System


Users Managing Their Own Encryption Keys

Using Transparent Database Encryption and Table space Encryption

Transparent database encryption and table space encryption provide secure encryption with automatic key management for the encrypted tables and table spaces. If the application requires protection of sensitive column data stored on the media, then these two types of encryption are a simple and fast way of achieving this.


If you do decide to have user-supplied or user-managed keys, then you must ensure you are using network encryption so that the key is not passed from the client to the server in the clear. You also must develop key archive mechanisms, which is also a difficult security problem. Key archives and backdoors create the security weaknesses that encryption is attempting to solve.

Changing Encryption Keys


Encrypting Binary Large Objects


Layouts of DES in C++ project:-

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