Data security is an exercise of protecting data from loss or destroys and unauthorized access. The purpose of data security is to insure secrecy while protecting private or organization data. Data is raw material that is not meaningful to user which stored in columns and rows in databases, servers and computers. All of these data are in a wide range from private data and intellectual property to financial analysis and top secrets. Data cover anything in interest that can be read by user and can be interpret in human form.
Anyway, some of the information isn't purposely leaved the system. The unauthorized access to data could cause large amount of troubles to big organization or even the home user. For example, bank account details can be stolen by someone else while this is affecting home user a lot, causing them involving in criminal actions or lost in their property.
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Lately, data security is having high attention by users, mostly is because of Internet. There are a lot of ways for to lock data from software to hardware. A computer user is now more conscious compare with the past, but is our data really secure? (Anonymous, 2006)
1.2. Definition of Encryption
Encryption is a translation of data into a secret code. It is the most useful way to protect data security. To read an encrypted file, you must have access to a private key or password that let you to decrypt and get the message. Unencrypted data is referred as plain text; data that has been encrypted is called cipher text.
E mail sent without encryption is like a postal card; others can see the contents if they use special tools to pry. With the use of encryption, only the recipient of the message can open and view the contents of the e mail.
It's like putting it in an envelope and sending it by registered mail. Data other than e mail can also be stored encrypted so that others cannot easily see its contents.
(Bossier Parish Community College, 2010)
For example, suppose that Victoria wants to send a private message to Sam. To do so, she first needs Sams public key; since everybody can see his public key, Sam can send it over the network in the clear without any concerns. Once Victoria has Sams public key, she will encrypt the message using Sams public key and sends it back to Sam. Sam receives Victorias message and, using his private key, decrypts it.
1.3. Why Encrypt?
The main goals of data security are Confidentiality, Integrity and Availability. Confidentiality means the data available on a system should be safe from unauthorized people; better examples would be customer credit card data, patient medical data in hospitals or personal data of employees in an organization. If that data is not secured, the company or the organization involved in that will eventually lose its reputation and business.
Integrity means the data available in an organization should be complete and whole. It shouldn't be altered by any unauthorized person. Intentional or unintentional attacks on the data will cause severe damage and finally the data becomes unreliable. One of the best examples would be account holders data in a Bank. If something happens to the banking data, it is devastating and the Bank will be in danger of losing its customers and business. In fact, in such cases, it may face a lawsuit too.
Availability is as important as Confidentiality and Integrity. It means the data requested or required by the authorized users should always be available. For example, assume that a company is hit by a hurricane and it has lost its computers and data. In such situations, the affected company should be able to install new computers and recover its data from backups. Suppose, if proper backups are not available, the concerned company cannot recover the data and resume its operation.
So whenever a company or an organization develops an application, it should focus on the above goals and accordingly develop the system, test it and release it with proper documentation.
(John Peter Jesan, 2006)
2. Data Encryption Techniques
2.1. Overview of Data Encryption Fields
Always on Time
Marked to Standard
Public key & Private key C Both users has a public and private key, the can communicate
by knowing each other's keys.
2.2. Key Based Encryption
Nowadays, random numbers is widely used by technology fields in encryption algorithms. Encryption is a way to protect data by changing meaningful words into cipher text that can only be decrypted and read by authorized personnel. The first encryption method being introduced was in the time of Romans by using manually encryption. Now it has been used by computer system to send data in a safety mode. One of the widely used encryption format is key based encryption.
In the most basic form of key based encryption, the sender encrypts the data using the encryption algorithm with a special key number plugged into it. On the receiving end, the same key must be used in order to decrypt the data.
A variation, known as public key encryption, uses two keys. In this case, one public key is used to encrypt data, and another private key is used to decrypt it on the other side. (Giles Cotter, 2002) This statement shows that, a public key encryption uses different key to encrypt and decrypts data, which is differ from private key encryption, uses the same key to encrypt and decrypts data.
These encryption methods use random numbers to produce their encryption keys. Due to the purpose of data security, the key must be very complex, and very hard to guess by others the real value of the data when they see the key. Hence, numbers generated must be as random as they could.
2.2.1. Public Key Encryption
The concept of public key encryption was introduced by Diffie and Hellman in 1976. The main point of this concept is the idea of using a one way function for encryption. The functions used for encryption belong to a special class of one way functions that remain one way only if some information (the decryption key) is kept secret. Again using informal terminology, we can define a public key encryption function as a map from plain text message units to cipher text message units that can be feasibly computed by anyone having the public key but whose inverse function cannot be computed in a reasonable amount of time without some additional information, called the private key.
This means that everyone can send a message to a given person using the same enciphering key, which can simply be looked up in a public directory whose contents can be authenticated by some means. There is no need for the sender to have made any secret arrangement with the recipient; in fact, the recipient also no need to have had any prior contact with the sender at all.
For example, if Sam wants to send a message to Victoria, he can search for Victorias public key and send it to her without making any secret arrangement with Victoria. And also, Victoria can read the message by decrypting it with the private key she have without informing Sam.
A possible reason for the late development of the concept of public key is that until the 1970's cryptography was used mainly for military and diplomatic purposes, for which symmetric key cryptography was well suited.
(Neal Koblitz, 2004)
However, with the increased computerization of economic life, new needs for cryptography arose. Unlike in the military or the diplomatic corps with rigid hierarchies, long term lists of authorized users, and systems of couriers in the applications to business transactions and data privacy one encounters a much larger and more fluid structure of cryptography users. Thus, perhaps public key cryptography was not invented earlier simply because there was no real need for it until recently.
Some of the purposes for which public key cryptography has been applied are:
a) Confidential message transmission
b) Identification systems, where users prove that they are authorized to have access to data or to a facility, or that they are who they claim to be
c) Authentication, which initiate that the message was sent by the someone ask for and that it hasn't been meddled
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d) Non repudiation, which watch against people that said that they will not to have agreed to something that they really agreed to
e) Key establishment, where two people are using the open airwaves and they want to agree up to a same secret key for use in some symmetric key cryptosystem
f) Electronic cash mechanisms that ensure spender anonymity
g) Electronic voting schemes that ensure that votes are confidential and correctly tallied.
These options will be perform through different types of protocols. The word Protocol means that orderly procedure in which people send messages to one another.
The path from an academic proposal for a new type of mathematical cryptography to its practical implementation is long and arduous. First of all, mathematicians and cryptographers must become convinced that the underlying number theoretic or combinatorial problem upon which the system's security relies is truly intractable. The only way to be more or less sure of this is to wait while experts try to find reasonably fast algorithms to break the cryptosystem; if they fail to do so after several years of trying, then one might believe that the problem is most likely an intrinsically difficult one. For example, most people believe that integer factorization, upon which RSA cryptography is based, is intractable (for at least the next few years) for integers of more than 300 decimal digits.
It would be nice, of course, to be able to prove theorems that state that such a problem cannot be efficiently solved. Ideally, such a theorem would show that the currently known algorithms are close to best possible. But unfortunately, no nontrivial theorems of that sort have been proved for any of the problems whose intractability is assumed in public key cryptosystems.
(Lantronix, Inc., 2006)
2.2.2. Private Key Encryption
Basic cryptographic algorithms split into two families: symmetric algorithms, otherwise known as secret key algorithms, which normally require a key to be shared and simultaneously kept secret within a restricted group, and public key algorithms where the private key is almost never shared. From outside, this may give the image that symmetric techniques have become out dated after the introduced of public key cryptography in the 1976.
(Microsoft Corporation, 2010)
Anyway, symmetric techniques are still being used by many people because only they can achieve some function in terms of higher speed and lower cost encryption, faster authentication, and useful hashing. Furthermore, nowadays we can see symmetric algorithms being used by mobile phones, credit cards, WLAN connections, and symmetric cryptology is also become a very popular research area.
Symmetric cryptography will uses same key to either encrypt or decrypt the data. That shows that both sender and receiver must own the same key. In the field of Internet, this encryption proved sufficient and accepted by cryptography. Symmetric cryptography brings new advantage over the old ones, but also some new problems. For example, cryptography has been widely use in the public, and normally large organization will cross over more than one country with thousands of workers, protecting the secret keys is a tough task. Risk of disclosing key will be much higher; therefore, it is hard for large organization to do so.
With the fast evolving of Internet, symmetric cryptography is in high usage and high accountability because sender and receiver can no need know each other.
The symmetric encryption scheme has five contents:
a) Plaintext: This is the original intelligible message or data that is fed to the algorithm as input.
b) Encryption algorithm: The encryption algorithm performs replacing and changing the arrangement on the plain text.
c) Secret Key: Secret key will also being added to the encryption algorithm. The exact substitutions and permutations performed depend on the key used, and the algorithm will produce a different output depending on the specific key being used at the time.
d) Cipher text: the output of cipher text will be a group of meaningless alpha numeric characters. It depends on the plaintext and the key. The cipher text is a random stream of data, as it stands, is unintelligible.
e) Decryption Algorithm: Decryption is just like the encryption algorithm but it run in reverse form. It uses the secret key and covert the cipher text into original plaintext.
There are two requirements for a symmetric key cryptosystem
a) The key need to be kept secret but the algorithm need not.
b) Sender and the receiver must have the copies of the secret key in a secure environment and must keep the key secure. If someone can find out the key and understand the algorithm, all communications by the key will be known. (Aladdin Knowledge Systems, Inc., 2000)
2.3. Comparison of Public Key Encryption and Private Key Encryption
Although asymmetric encryption provides much more functionality compare with symmetric encryption, in some areas the symmetric encryption are still the best solution, and does the job as securely and more efficiently. Due to its nature, symmetric technology is far less expensive to implement.
The two methods of encryption will be compared in below table:
2.4. Strengths and Weaknesses of Public and Private Key Encryption
2.4.1. Public Key Encryption
The asymmetric nature of public key cryptography allows it a sizable advantage over symmetric key algorithms. The unique private and public keys provided to each user allow them to conduct secure exchanges of information without first needing to devise some way to secretly swap keys. This glaring weakness of private key cryptography becomes a crucial strength of public key encryption.
The biggest obstacle in successfully deploying a symmetric key algorithm is the necessity for a proper exchange of private keys. This transaction must be completed in a secure manner. In the past, this would often have to be done through some type of face to face meeting, which proves quite impractical in many circumstances when taking distance and time into account. If one assumes that security is a risk to begin with due to the desire for a secret exchange of data in the first place, the exchange of keys becomes further complicated.
Another problem concerns the compromise of a private key. In symmetric key cryptography, every participant has an identical private key. As the number of participants in a transaction increases, both the risk of compromise and the consequences of such a compromise increase dramatically. Each additional user adds another potential point of weakness that an attacker could take advantage of. If such an attacker succeeds in gaining control of just one of the private keys in this world, every user, whether there are hundreds of users or only a few, is completely compromised.
(Matt Blumenthal, 2007)
2.4.2. Private Key Encryption
The private keys used in symmetric key cryptography are robustly resistant to brute force attacks. While only the one time pad, which combines plaintext with a random key, holds secure in the face of any attacker regardless of time and computing power, symmetric key algorithms are generally more difficult to crack than their public key counterparts. Additionally, secret key algorithms require less computing power to be created than equivalent private keys in public key cryptography.
Keys in public-key cryptography, due to their unique nature, are more computationally costly than their counterparts in secret-key cryptography. Asymmetric keys must be many times longer than keys in secret-cryptography in order to boast equivalent security. Keys in asymmetric cryptography are also more vulnerable to brute force attacks than in secret-key cryptography. There exist algorithms for public-key cryptography that allow attackers to crack private keys faster than a brute force method would require. The widely used and pioneering RSA algorithm has such an algorithm that leaves I susceptible to attacks in less than brute force time. While generating longer keys in other algorithms will usually prevent a brute force attack from succeeding in any meaningful length of time, these computations become more computationally intensive. These longer keys can still vary in effectiveness depending on the computing power available to an attacker.
Public-key cryptography also has vulnerabilities to attacks such as the man in the middle attack. In this situation, a malicious third party intercepts a public key on its way to one of the parties involved. The third party can then instead pass along his or her own public key with a message claiming to be from the original sender. An attacker can use this process at every step of an exchange in order to successfully impersonate each member of the conversation without any other parties having knowledge of this deception. (Matt Blumenthal, 2007)
2.5. Critical Evaluation
To protect data you have backed up, symmetric encryption is preferable because the key is created, stored, and deleted locally, so the user backing up the data has control over the key. The fewer people that have access to the key, the more secure the encrypted data. A public key encryption method trusts the key value to an outside party; symmetric encryption protects the key with even greater securitylocal control. Along with control come extra steps to protect the key.
That means your site needs to put procedures in place so you protect the key, and at the same time, can quickly identify and retrieve the key when you need to decrypt the data.
As with most IT procedures, encryption best practices are simply a well thought-out series of standard tasks. Assuming that the encryption solution you are using enforces strong encryption, such as AES-256 (the federally approved encryption algorithm considered to be unbreakable), then the rest of the encryption best practices are simply a codification of common sense that includes:
? Having an overall security plan that includes the encryption of backed up data and defines the sets of data to be encrypted
? Identifying who can access encryption features and encrypted data
? Protecting key access with passwords and key nicknames to shield the key so that the real key is never displayed as plain text
? Making backup copies of encryption keys
? Identifying how to track keys, passwords, and encrypted data
3. Database Encryption
A database encryption scheme should meet several requirements. Among them are the requirements for data security, high performance, and detection of unauthorized modifications. Inspired by that pioneer work in the field, there are a few requirements that relate to the practicality of such an encryption solution. Each requirement will be discussed in details in the following subsections.
3.1. Database Security- Model and Attacks
3.1.1. Database operational model
As with current database systems, when discussing the model for database encryption we assume a client-server scenario. The client has a combination of sensitive and non-sensitive data stored in a database at the server. Whether or not the two parties are collocated does not make a difference in terms of security. The servers added responsibility is to protect the clients sensitive data, i.e., to ensure its confidentiality and its integrity.
This model has three major points of vulnerability with respect to client data:
a) Data-in-motion - All client-server communication can be secured through standard means, e.g., an SSL connection, which is the current de facto standard for securing Internet communication. Therefore, communication security poses no real challenge and we ignore it in the remainder of this paper.
b) Data-in-use - An adversary can access the memory of the database software directly and extract sensitive information. This attack can be prevented using a tampered proof hardware for protecting the database server's memory.
c) Data-at-rest - Typically, DBMSs protect stored data through access control mechanisms. However, its goals should not be confused with those of data confidentiality since attacks against the stored data may be performed by access to the database files follow by a path instead of through the database software, physically remove the storage media or by access to backup files.
Different security mechanisms can be categorized based on the level of trust in the database server, which can range from fully trusted to fully un-trusted:
a) Fully trusted - In this scenario, the server can perform all of the operations and no threat exists. Obviously this scenario is not of our interest, and is ignored in the remainder of this paper.
b) Fully un-trusted - In this scenario, a client does not even trust the server with clear text queries; hence, it involves the server performing encrypted queries over encrypted data. This scenario corresponds to the Database as a Service (DAS) model.
c) Partially trusted C The database server itself together with its memory and the DBMS software is trusted, but the secondary storage is not. (Erez Shmueli, 2009)
3.1.2. Types of Attacks
a) Passive Attacks
In an encrypted database, the secure index should not give any information of plaintext values in database. The possible information leaks were as below:
Static leakage - at a particular time, observe snapshot of the database to gain information on the plain text value of the database. For example, if the database is encrypted where same plaintext values is being encrypted to same cipher text values, information about the plaintext, such as their frequencies can easily be learned.
Linkage leakage C Linking a table value to its position index can also easily to gain information on the plain text value. For example, if the table value and the index value are same, an observer can find in the table cipher text value in the index, and predict the plaintext value.
Dynamic leakage C By see through and analyze the changes happened in database over a period of time, the information of plaintext value can be obtained. For example, some one can observe the index for a period of time, the person can estimate its plaintext value based on its position in the index.
b) Active Attacks
Passive attacks are only observing the database while active attacks will modify the database. Active attacks are more troublesome because they may mislead the user. The modifications can happen in a few ways.
Spoofing - Replacing a cipher text value with a generated value. Assuming that the encryption keys are secure, a possible attacker might try to generate a valid cipher text value, and substitute the current valid value stored on the disk. Assuming that the encryption keys were not compromised, this attack poses a relatively low risk.
Splicing - Replacing a cipher text value with a different cipher text value. Under this attack, the encrypted content from a different location is copied to a new location under attack.
Replay - Replaced a cipher text value with older version that has been updated or deleted. (Erez Shmueli, 2009)
3.2. Types of Encryption to Overcome
Added security measures typically introduce significant computational overhead to the running time of general database operations. However, it is desirable to reduce this overhead to the minimum that is really needed, and thus:
? It should be possible to encrypt only sensitive data while keeping insensitive data unencrypted.
? Only data of interest should be encrypted/decrypted during queries' execution.
? Some vendors do not permit encryption of indexes, while others allow users to build indexes based on encrypted values. The latter approach results in a loss of some of the most obvious characteristics of an index C range searches, since a typical encryption algorithm is not order-preserving. In addition, it is desirable that the encrypted database should not require much more storage than the original one.
3.2.1. File-System Encryption
The encryption scheme presented in suggested encrypting whole disk so that database can be protected. The main disadvantage of this scheme is that the entire database is encrypted using a single encryption key, and thus discretionary access control cannot be supported.
3.2.2. DBMS-Level Encryption
Several database encryption schemes have been proposed in the literature. The one presented in is based on the Chinese-Reminder theorem, where different sub-keys are used to encrypt different cells for each. This scheme enables encryption at the rows and also cells. Another scheme, presented in, extends the encryption scheme presented in, by supporting multilayer access control. It classifies subjects and objects into distinct security classes that are ordered in a hierarchy, such that an object with a particular security class can be accessed only by subjects in the same or a higher security class. The scheme presented in proposes encryption for a database based on Newton's interpolating polynomials.
(Jingmin He, 2001)
The database encryption scheme presented in is based on the RSA public-key scheme and suggests two database encryption schemes: one column oriented and the other row oriented. One disadvantage of all the above schemes is that the necessary element in a database is row instead of cell, so the structure of database needs to be modified. In addition, all of the cells and rows need to be modified according to the schemes. Thus, in order to perform an update operation, all the encryption keys should be available.
The SPDE scheme which encrypts each cell in the database individually together with its cell coordinates (table name, column name and row-id). In this way static leakage attacks are prevented since equal plaintext values are encrypted to different cipher-text values. Furthermore, splicing attacks are prevented since each cipher-text value is correlated with a specific location, trying to move it to a different location will be easily detected. Further security analysis and fixes to this scheme can be found in. ( Erez Shmueli, 2009)
3.2.3. Application-Level Encryption
In Web Data Service Provider Middleware (WDSP) application is suggested which translates the user queries into a new set of queries which execute of the encrypted DBMS. The model was implemented as the DataProtector1 System which serves as an http level rule-based middleman who regulates access to secure data stored on web service provider. The solution is attractive to public data storage, backup and sharing services which are very popular on the web nowadays.
( Erez Shmueli, 2009)
3.2.4. Client-Side Encryption
The highly raised Internet usage, and also advance improvement in software and networking, has brought to ease of sharing data for a variety of purposes. This cause the process of database management is being outsourced by organizations to cut down their costs and so that they can concentrate on the core business. One fundamental problem with this architecture (besides performance degradation due to remote access to data) is data privacy. That is, sensitive data have to be securely stored and protected against untrustworthy servers. Encryption is one promising solution to this problem.
Defining the encryption scheme under the assumption that the server is not trusted, raises the question of how a query is evaluated if data has been encrypt while the server cannot access to the encryption keys.
(Erez Shmueli, 2009)
3.3. Critical Evaluation
Database attacks can directly shows their effects on economy. It is more advances nowadays and will lead to data loss which is critical to run day-to-day transaction, from payment, customer information, inventory tracking and so on. Furthermore, database also will store private and confidential information of customer such as credit card numbers, health record, and financial situations and so on. If customer information is exposed, it might affect the relationships between organization and customer.
The source of threats to databases can be caused by hackers, network, or maybe internal employees that can bypass to the organizations firewall. Firewalls are a layer of protection that can help organization to keep unauthorized people from accessing to organizations network so the trend of protecting data nowadays is more about letting the right people has access right into the network. As a result, the vulnerability of attack on a database will grow accordingly to the complexity of a system where a database has been placed in. if organizations continue in their traditional style of keeping all their data without any encryption techniques used, the organizations privacy is definitely at a high risk level. Taking the right security approach enables business and protects critical data.
In a conclusion, a good database encryption will need to have the following characteristics:
? Protect data in both database and storage system
? Enforce privileges at the field/user level
? Separate security policy from data management
? Protect encryption keys
? Audit and report access to sensitive data
4. Critical Evaluation
Generally, encryption is readily available in some software, for example, Adobe Reader and Microsoft Word. For Adobe Reader, you can encrypt the file so that it can only be opened with a password. There will be two password being used, which is user password for opening the document and master password for changing the security settings and the user password.
However, the encryption level of Adobe Reader is still low because file with security options contain everything needed for opening the file. Using a 3rd party software is possible to break down the encryption. Cracker software does not need to recover the password, but only apply the documented algorithm for opening the protected PDF. The encryption algorithm used by Adobe Reader is RC4 with 40 bits key which commonly used in hardware and software products such as web browsers. In fact 40 bits dont provide much security. There are some facts to support this statement while long encryption keys cannot compensate for a poor choice of passwords. For 128-bit encrypted PDF files, if you are using ElcomSoft to crack, it takes 22 minutes to break a 4 characters password, 9days for 5 characters password, 42 days for 6 characters password and for years to crack password which contains more than 7 characters. Weak passwords instead of strong one result in shorter cracking time. As Adobe Readers recommendations, we should use more digits, punctuation and other special characters in our passwords and it should exist length of at least 8 characters.
(John C. A. Bambenek, 2008)
From the above case we can see that, security is not on encryption because no encryption is perfect. There is no doubt that strong encryption is needed, especially for information that shouldnt be expose. There is no sturdy guarantee to say that all of the path between endpoints of message will be secure, in simple words, the message need to be hide during transmission to make it secure. If brute-force is used to decrypt message, the process of encryption by using modern forms is no longer valuable.
If the endpoints between communication messages are vulnerable, there will still have risk. At the very last step, the encrypted message needs to be decrypt so that they are meaningful and useful to users, and this process will occurs at the end of the message transmission. There is a problem with this, is the endpoints of both message has been compromised, the whole message can be stolen although the original unencrypted text is not store in the system.
As Bruce Scheneier often comments, Security is a process, not a product. Poorly used security techniques, especially encryption techniques are often a greater liability to use than not. In a simple word, if encryption is used in such ways that voids the promise of confidentiality or integrity, then the user is worse off than they had not used encryption to begin with. Besides of wasting machine resource, they also wasting their time to perform useless encryption operations. They also have a false sense of security and more vulnerable in their mindset. Encryption needs to be accompanied by server hardening, intrusion detection, firewalls, and auditing. Without it, encryption is easily compromised.
In data security issue, encryption is not everything, besides of preventing from being attack, user must also need to confirm their data is in a safe place, which is back up every of your important data. Encryption can helps to keep secrets, provide signatures, keeps anonymity provided no human errors occur. No human is perfect, every human make mistakes and this will cause to data fraud.
Nowadays, organizations need encryption in their business too. An organization wont success if they fail to protect customer data and proprietary business information which can lead to serious consequences. Fail to protect data may cause an organization lost their customer and hard to find a new one, spoilt their brand image, or even fail their business and fail to meet the business commitment.
In response to increasing demands for enterprise data protection, more organizations are planning strategically for their encryption needs. 21 percents of organizations surveyed now have an encryption strategy applied consistently across the organization, up from 16 percent in 2007. 74 percent organizations have some type of encryption strategy either enterprise-wide or applied based on the type of data or applications used. As expected, leading IT organizations with the most effective security programs (high SESs) are the ones at the forefront of this strategic planning trend and continued to improve the effectiveness of their IT organizations in 2008.
(Ponemon Institute, LLC, 2008)
Anyway, still the same issue; encryption is not everything to enterprise. Its a common trend to think that if data that being encrypt has been strengthen its security, is that encryption makes everything secure? Regarding to the involvement of encryption in the whole database, all data must be decrypt so that they can be read, update or delete and the encryption must not affect the normal daily access control. Encryption is an operation which is highly related to performance, if all the data is encrypted, of course the performance of the system will be affected. Availability is the main point of evaluating security issue, normally we use encryption to protect data, but if due to unskillful person cause data loss because of encryption, or the performance has affect the availability of the data, in fact it will be a new security problem.
One of the best practices for encryption is to change the encryption key regularly. In fact this will cause the production database inaccessible by someone when the data has been decrypt then encrypt with new key. This is one of the main points that lower the level of availability.
In addition, if you wish to encrypt all or most data in a production database, it will bring problems. It may be an advantage for data that is store offline. A good example will be backup data of a production database that will store at a remote location for every 6 months. If all of the data in use being encrypted, when you want to use back the data, it needs time to decrypt, this will also take time and affect performance of the system.
Copies of digital data can be sent worldwide with a click, so the old method of controlling data by deleting it is an obsolete concept. In the digital age, the best way to control data is to encrypt it.
As we move toward a society where automated information resources are increasingly shared, cryptography will continue to increase in importance as a security mechanism. Electronic networks for banking, shopping, inventory control, benefit and service delivery, information storage and retrieval, distributed processing, and government applications will need improved methods for access control and data security. The DES algorithm has been a successful effort in the early development of security mechanisms.
It is the most widely analyzed, tested, and used crypto algorithm and it will continue to be for some time yet to come. By using a strong encryption method, once you have selected a strong encryption method, a sturdy security practice must be implement so that it can control and make sure that people who wants to access to the database that has been encrypt is authorized person. The security practices is to make sure that encryption keys is store in a safe place, and also being copied and backup for restore purpose while passwords will be used to strengthen the level of security.
Of course, additional layers of procedure and security are often available through your encryption system. These best practices let easily manage your encrypted data, and keep encryption keys safe and still accessible when you need to recover data.
(Sun Microsystems, 2007)