Key Databases

Each cryptographic service provider (CSP) has a key database in which it stores persistent cryptographic keys. Each key database contains one or more key containers, each of which contains all the key pairs belonging to a specific user. The following illustration showsthe relationship between CSPs, key databases, and key containers.

The CSP stores each key container from session to session, including all of the public/private key pairs that it contains. However, session keys are not automatically persisted to any permanent storage media.
Generally, a default key container is created for each user. Default key containers have a default name.
An application can create its own key container and key pairs, and assign a name to the key container. A key is created for each user and each machine. For each user, the key container is located in the HKEY_CURRENT_USER\Comm\Security\Crypto registry key. For each machine, the key container is located in the HKEY_LOCAL_MACHINE\Comm\Security\Crypto registry key.
CryptoAPI encrypts the contents of the key container using the CryptProtectData function. Note that all applications can read and decrypt both user and machine keys by calling CryptUnprotectData on the encrypted key contents.

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Hashing and Digital Signature Algorithms

This section lists several algorithms used to compute hashes and digital signatures. Each of these algorithms is supported by the Microsoft RSA Base Provider.
The MD2, MD4, and MD5 hashing algorithms were all developed by RSA Data Security, Inc. These algorithms were developed in sequential order. The later algorithms are generally more secure than the earlier ones. All three algorithms generate 128-bit hash values.
The secure hashing algorithm (SHA) was developed by the National Institute of Standards and Technology (NIST) and by the National Security Agency (NSA). This algorithm was developed for use with digital signature algorithm (DSA) or Digital Signature Standard (DSS). This algorithm generates a 160-bit hash value.
Message authentication codes are similar to hash values, but are computed using a session key. Because of this, you must possess the session key to recompute the hash value to verify that the base data has not changed.
The message authentication codes implemented by the Microsoft RSA Base Provider are of the most common sort. That is, they are block cipher message authentication codes. This method encodes the base data with a block cipher and then uses the last encoded block as the hash value. The encryption algorithm used to build the Message Authentication Code is the one that was specified when the session key was created.

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Digital SIgnature

What is a Digital Signature? An introduction to Digital Signatures, by David Youd

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Bob

(Bob's public key) (Bob's private key)

Bob has been given two keys. One of Bob's keys is called a Public Key, the other is called a Private Key.

Bob's Co-workers:
				Anyone can get Bob's Public Key, but Bob keeps his Private Key to himself
Pat	Doug	Susan

Bob's Public key is available to anyone who needs it, but he keeps his Private Key to himself. Keys are used to encrypt information. Encrypting information means "scrambling it up", so that only a person with the appropriate key can make it readable again. Either one of Bob's two keys can encrypt data, and the other key can decrypt that data.
Susan (shown below) can encrypt a message using Bob's Public Key. Bob uses his Private Key to decrypt the message. Any of Bob's coworkers might have access to the message Susan encrypted, but without Bob's Private Key, the data is worthless.

"Hey Bob, how about lunch at Taco Bell. I hear they have free refills!"

HNFmsEm6Un BejhhyCGKOK JUxhiygSBCEiC 0QYIh/Hn3xgiK BcyLK1UcYiY lxx2lCFHDC/A

HNFmsEm6Un BejhhyCGKOK JUxhiygSBCEiC 0QYIh/Hn3xgiK BcyLK1UcYiY lxx2lCFHDC/A

"Hey Bob, how about lunch at Taco Bell. I hear they have free refills!"

With his private key and the right software, Bob can put digital signatures on documents and other data. A digital signature is a "stamp" Bob places on the data which is unique to Bob, and is very difficult to forge. In addition, the signature assures that any changes made to the data that has been signed can not go undetected.

To sign a document, Bob's software will crunch down the data into just a few lines by a process called "hashing". These few lines are called a message digest. (It is not possible to change a message digest back into the original data from which it was created.)

Bob's software then encrypts the message digest with his private key. The result is the digital signature.

Finally, Bob's software appends the digital signature to document. All of the data that was hashed has been signed.

Bob now passes the document on to Pat.

First, Pat's software decrypts the signature (using Bob's public key) changing it back into a message digest. If this worked, then it proves that Bob signed the document, because only Bob has his private key. Pat's software then hashes the document data into a message digest. If the message digest is the same as the message digest created when the signature was decrypted, then Pat knows that the signed data has not been changed.

Plot complication...

Doug (our disgruntled employee) wishes to deceive Pat. Doug makes sure that Pat receives a signed message and a public key that appears to belong to Bob. Unbeknownst to Pat, Doug deceitfully sent a key pair he created using Bob's name. Short of receiving Bob's public key from him in person, how can Pat be sure that Bob's public key is authentic?

It just so happens that Susan works at the company's certificate authority center. Susan can create a digital certificate for Bob simply by signing Bob's public key as well as some information about Bob.

Bob Info:     Name     Department     Cubical Number Certificate Info:     Expiration Date     Serial Number Bob's Public Key:

Now Bob's co-workers can check Bob's trusted certificate to make sure that his public key truly belongs to him. In fact, no one at Bob's company accepts a signature for which there does not exist a certificate generated by Susan. This gives Susan the power to revoke signatures if private keys are compromised, or no longer needed. There are even more widely accepted certificate authorities that certify Susan.
Let's say that Bob sends a signed document to Pat. To verify the signature on the document, Pat's software first uses Susan's (the certificate authority's) public key to check the signature on Bob's certificate. Successful de-encryption of the certificate proves that Susan created it. After the certificate is de-encrypted, Pat's software can check if Bob is in good standing with the certificate authority and that all of the certificate information concerning Bob's identity has not been altered.
Pat's software then takes Bob's public key from the certificate and uses it to check Bob's signature. If Bob's public key de-encrypts the signature successfully, then Pat is assured that the signature was created using Bob's private key, for Susan has certified the matching public key. And of course, if the signature is valid, then we know that Doug didn't try to change the signed content.

Although these steps may sound complicated, they are all handled behind the scenes by Pat's user-friendly software. To verify a signature, Pat need only click on it. 

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DATA BASE MANAGEMENT SYSYTEM(DBMS)

WHAT IS DATA?
Data is the name given to facts or entities such as names and numbers. e.g.  Weight, prices, marks etc.

WHAT IS INFORMATION?
Information is the data that has been covered into more useful forms.

WHAT IS DATABASE?
A database can be defined as a collection of coherent, meaningful data (information) or database is the facts or information placed in an organized form.

Without any organization information has no meanings.

A database is an organized collection of data that is useful to us. The data inside in a database can be modified, deleted or new data can be added. They are stored in the form of records as shown in the table below:

EMP_ID	EMP_NAME	AGE	SALARY
1101	SIMRAN	21	22000

The above table shows a single record. The columns-Emp_id, Emp_Name, Age, Salary are the fields or attributes, while the row containing the corresponding the values-1101, Ana, 28, 15000 is a single record. There can be a number of records in a table and number of tables in a database. The tables in a database are related to each other through one/more attributes/fields.

Database is of two types:
1.    Manual databases: Databases created by human beings without any support of computer is known as manual databases.
2.    Computer based databases: Databases created with the help of computer are known as computer based databases.

Computer based databases are of two types:

A. Tradition files processing system
B. Database approach

What Is DBMS?
It stands for database management system. It is a software system that allows the users to define, create and manipulate database and provides a control to the database.

Components of DBMS:
1.    Hardware
2.    Software
3.    Data
4.    Procedures
5.    Users
Advantages of DBMS:
1.    Controlling Redundancy: In file system, each application has its own private files, which can’t be shared between multiple applications. This can often lead to considerable redundancy in the stored data, which results in wastage of storage space. In DBMS by having centralized database this can be avoided.
2.    Integrity can be enforced: Integrity of data means that data in database is always accurate, such that inaccurate information cannot be stored in database.
3.    Standards can be enforced: Since DBMS is a central system, so standard can be enforced easily may be at company level, department level, national level or international level.
4.    Inconsistency can be avoided: When the same data is duplicated and changes are made at one site, which is not propagated to the other site, it gives rise to inconsistency and the two entries regarding the same data will not agree. At such time the data is said to be inconsistent. So if redundancy is removed chances of having inconsistent data is also removed.
5.    Data can be shared: DBMS is a centralized system in which data can be shared by multiple applications.
Disadvantages of DBMS:
1. Complexity: The provision of the functionality that is expected of a good DBMS makes the DBMS an extremely complex piece of software.
2. Size: The complexity and breadth of functionality makes the DBMS an extremely large piece of software, occupying many megabytes of disk space and requiring substantial amount of memory to run efficiently.   
3.  Performance: Performance is slow as compared to file processing system.
4. Higher impact of failure: In DBMS system failure of any component can bring operations to a halt.
5. Cost: Cost of DBMS is very high. It varies significantly, depending on the environment and functionality provided.

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Oracle

INTRODUCTION TO ORACLE

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A relational model, made by Dr. E.F Codd in 1970, sponsored by IBM, accepted as definitive model for RDBMS. This language developed by IBM to manipulate the data stored within Codd’s model was originally called Structured English Query Language(SEQUAL) with the word English later being dropped in favor Structured Query Language(SQL).

In 1979 a company called Relation Software, Inc. released the first commercially available implementation of SQL. Relation Software later came to be known as Oracle Corporation. Oracle corporation is a company that produces the most widely used, Server based, Multi user RDBMS named Oracle.

FEATURES OF ORACLE:

1.    Very Large Memory Support:

Oracle allows Very Large Memory (VLM) configuration in Window 2000 and Window XP, which allows Oracle to access more than 4GB RAM.

2.    4GB RAM TUNING(4GT):

Window NT Server Enterprise and Datacenter Editions include a feature called 4GB RAM TUNING(4GT).This feature allows memory-intensive applications running on Oracle

3.    VLM INSTANCE TUNING:

VLM configuration improves database performance by caching more database buffers in memory.

4.    USER MIGRATION UTILITY:

A new command-line tool, User Migration Utility, simplifies conversion of local or external database users to enterprise users.

5.    ORACLE SHARED SERVER PROCESS:

It is a server configuration which allows many user processes to share very few server processes. The user processes connect to a dispatcher background process, which routes client requests to the next available shared server process.

6.    ORACLE NET MULTIPLEXING AND CONNECTION POOLING:

Oracle net multiplexing and connection pooling features allow a large configuration to connect more users to a single database instance.

7.    ORACLE REAL APPLICATION CLUSTERS:

This clusters raises connection counts dramatically by allowing multiple server computers to access the same database files, increasing the number of user connections by tens of thousands, as well as increasing throughput

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DBMS SQL Queries

Command: Create

Purpose: This command is used to create tables.

Syntax: Create table <table name> (column 1 data type<size>, column 2 data type <size>);

Example::SQL> create table student2(s_no varchar2(4), name char(15), roll_no varchar2(6), branch char(10));
 

Command: Desc

Purpose: This command is used to describe table.

Syntax: desc <table name>;

Example::
SQL> desc student2;
Name Null? Type
  Command: Insert

Purpose: This command inserts values in the table.

Syntax: Insert into table name (col name 1, column name 2) values (value1, value2);

Example::
SQL> insert into student2 values (1,'AMAN', 7213,'c.s.e.');

SQL> insert into student2 values (2,'ANKIT’, 7216,'c.s.e.');

SQL> insert into student2 (s_no,name,branch) values(3,' ADITYA',7206,'c.s.e.');
  Command: Select

Purpose: Selects all columns and rows from table,* and distinct are the options used with it.

Syntax: Select [distinct] <tablename.columnname>
From<tablename>
[Where <condition>]
[Group by<columnname(s)>]
[Having <condition>]
[Order by <expression>];

Example::
SQL> select * from student2;

SQL> select * from student2 where name='ANKIT';

SQL> select * from student2 where s_no=3;
  Command: Alter

Purpose: This is used to modify the structure of the table.

Syntax: Alter table name add<new column datatype<size>;

Example::
SQL> alter table student2 add( address varchar2(25));

SQL> select * from student2;

SQL> alter table student2 modify( address varchar(28));

SQL> alter table student2 drop(address);

SQL> select * from student2;
  Command: Delete

Purpose: This command is used to delete all the rows or either a set of rows from a table.

Syntax: Delete from <table name>;
Delete from <table name> where <condition>;

Example::
SQL> delete from student2 where name='purneet';

SQL> select * from student2;

SQL> delete from student2;

SQL> select * from student2;
  Command: Update

Purpose: This command is used to change and modify the data values in a table.

Syntax:Update <table name>set<column name1>=<expresson1>, < column name2>=<expresson2>;

Example::
SQL> update student2 set name='AKSHAY' where s_no=3;

SQL> select * from student2;
  Command: Rename

Purpose: This command is used to rename a table.

Syntax: Rename<table name> to <new table name>;

Example::
SQL>rename student2 to student;

SQL> select * from student;
  Command: Order by command

Purpose: The ORDER BY clause sorts the result set based on the columns specified.

Syntax: Order by<column name1>, <column name2> <[sort order]>;

Example::
SQL> select * from student2 order by roll_no asc;

SQL> select * from student2 order by s_no asc;

SQL> select * from student2 order by s_no desc;

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