java

java

Java is a general-purpose computer programming language that is concurrent, class-based, object-oriented,^[14] and specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA),^[15] meaning that compiled Java code can run on all platforms that support Java without the need for recompilation.^[16] Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless ofcomputer architecture. As of 2016, Java is one of the most popular programming languages in use,^{[17][18][19][20]} particularly for client-server web applications, with a reported 9 million developers.^[21] Java was originally developed by James Gosling at Sun Microsystems (which has since been acquired by Oracle Corporation) and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++, but it has fewer low-level facilities than either of them.

Versions

Main article: Java version history

As of 2015, only Java 8 is officially supported. Major release versions of Java, along with their release dates:

• JDK 1.0 (January 23, 1996)^[38]
• JDK 1.1 (February 19, 1997)
• J2SE 1.2 (December 8, 1998)
• J2SE 1.3 (May 8, 2000)
• J2SE 1.4 (February 6, 2002)
• J2SE 5.0 (September 30, 2004)
• Java SE 6 (December 11, 2006)
• Java SE 7 (July 28, 2011)
• Java SE 8 (March 18, 2014)

• Use outside of the Java platform

• The Java programming language requires the presence of a software platform in order for compiled programs to be executed. Oracle supplies the Java platform for use with Java. The Android SDK, is an alternative software platform, used primarily for developing Android applications.

Android

what is ardroid 

Android (stylized as android) is a mobile operating system developed by Google, based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablets. Android's user interface is mainly based ondirect manipulation, using touch gestures that loosely correspond to real-world actions, such as swiping, tapping and pinching, to manipulate on-screen objects, along with a virtual keyboard for text input. In addition to touchscreen devices, Google has further developed Android TV for televisions, Android Auto for cars, and Android Wear for wrist watches, each with a specialized user interface. Variants of Android are also used on notebooks, game consoles, digital cameras, and other electronics

hardwave 

The main hardware platform for Android is the ARM (ARMv7 and ARMv8-A architectures), with x86 and MIPS architectures also officially supported in later versions of Android. The unofficial Android-x86 project provided support for the x86 architectures ahead of the official support.^[6][90] MIPS architecture was also supported before Google did. Since 2012, Android devices with Intelprocessors began to appear, including phones^[91] and tablets. While gaining support for 64-bit platforms, Android was first made to run on 64-bit x86 and then on ARM64. Since Android 5.0 "Lollipop", 64-bit variants of all platforms are supported in addition to the32-bit variants.

Software stack

On top of the Linux kernel, there are the middleware, libraries and APIs written in C, and application softwarerunning on an application framework which includes Java-compatible libraries. Development of the Linux kernel continues independently of other Android's source code bases.

Speech recognition

Speech recognition (SR) is the inter-disciplinary sub-field of computational linguistics that develops methodologies and technologies that enables the recognition andtranslation of spoken language into text by computers. It is also known as "automatic speech recognition" (ASR), "computer speech recognition", or just "speech to text" (STT). It incorporates knowledge and research in the linguistics, computer science, and electrical engineering fields.

Speech recognition is the ability of a machine or program to identify words and phrases in spoken language and convert them to a machine-readable format. Rudimentary speech recognition software has a limited vocabulary of words and phrases, and it may only identify these if they are spoken very clearly.

how to work on speech recognition

An ADC translates the analog waves of your voice into digital data by sampling the sound. The higher the sampling and precision rates, the higher the quality. To convert speech to on-screen text or a computer command, a computer has to go through several complex steps. When you speak, you create vibrations in the air.

Fingerprint recognition

Fingerprint recognition or fingerprint authentication refers to the automated method of verifying a match between two human fingerprints. Fingerprints are one of many forms of biometrics used to identify individuals and verify their identity.

 

 A fingerprint sensor is an electronic device used to capture a digital image of the fingerprint pattern. The captured image is called a live scan. This live scan is digitally processed to create a biometric template (a collection of extracted features) which is stored and used for matching. Many technologies have been used including optical, capacitive, RF, thermal, piezoresistive, ultrasonic, piezoelectric, MEMS.^[1] This is an overview of some of the more commonly used fingerprint sensor technologies.

Optical

Optical fingerprint imaging involves capturing a digital image of the print using visible light. This type of sensor is, in essence, a specialized digital camera. The top layer of the sensor, where the finger is placed, is known as the touch surface. Beneath this layer is a light-emitting phosphor layer which illuminates the surface of the finger. The light reflected from the finger passes through the phosphor layer to an array of solid state pixels (a charge-coupled device) which captures a visual image of the fingerprint. A scratched or dirty touch surface can cause a bad image of the fingerprint. A disadvantage of this type of sensor is the fact that the imaging capabilities are affected by the quality of skin on the finger. For instance, a dirty or marked finger is difficult to image properly. Also, it is possible for an individual to erode the outer layer of skin on the fingertips to the point where the fingerprint is no longer visible. It can also be easily fooled by an image of a fingerprint if not coupled with a "live finger" detector. However, unlike capacitive sensors, this sensor technology is not susceptible to electrostatic discharge damage.^[4]
Fingerprints can be read from a distance.^[2]

Ultrasonic

Ultrasonic sensors make use of the principles of medical ultrasonography in order to create visual images of the fingerprint. Unlike optical imaging, ultrasonic sensors use very high frequency sound waves to penetrate the epidermal layer of skin. The sound waves are generated using piezoelectric transducers and reflected energy is also measured using piezoelectric materials. Since the dermal skin layer exhibits the same characteristic pattern of the fingerprint, the reflected wave measurements can be used to form an image of the fingerprint. This eliminates the need for clean, undamaged epidermal skin and a clean sensing surface.^[5][3] LeEco became the first company to introduce this in Smartphone.^[4]

Capacitance

Capacitance sensors use principles associated with capacitance in order to form fingerprint images. In this method of imaging, the sensor array pixels each act as one plate of a parallel-plate capacitor, the dermal layer (which is electrically conductive) acts as the other plate, and the non-conductive epidermal layer acts as a dielectric.
The iPhone 6 uses a capacitance fingerprint sensor.^[5

Passive capacitance

A passive capacitance sensor use the principle outlined above to form an image of the fingerprint patterns on the dermal layer of skin. Each sensor pixel is used to measure the capacitance at that point of the array. The capacitance varies between the ridges and valleys of the fingerprint due to the fact that the volume between the dermal layer and sensing element in valleys contains an air gap. The dielectric constant of the epidermis and the area of the sensing element are known values. The measured capacitance values are then used to distinguish between fingerprint ridges and valleys.^[6]

Active capacitance

Active capacitance sensors use a charging cycle to apply a voltage to the skin before measurement takes place. The application of voltage charges the effective capacitor. The electric field between the finger and sensor follows the pattern of the ridges in the dermal skin layer. On the discharge cycle, the voltage across the dermal layer and sensing element is compared against a reference voltage in order to calculate the capacitance. The distance values are then calculated mathematically, and used to form an image of the fingerprint.^[7] Active capacitance sensors measure the ridge patterns of the dermal layer like the ultrasonic method. Again, this eliminates the need for clean, undamaged epidermal skin and a clean sensing surface.^[7]

 

What is ethical hacking?

Ethical hacking is identifying weakness in computer systems and/or computer networks and coming with counter measures that protect the weaknesses. Ethical hackers must abide by the following rules.

• Get written permission from the owner of the computer system and/or computer network before hacking.
• Protect the privacy of the organization been hacked.
• Transparently report all the identified weaknesses in the computer system to the organization.
• Inform hardware and software vendors of the identified weaknesses.

Why ethical hacking?

• Information is one of the most valuable assets of an organization. Keeping information secure can protect an organization’s image and save an organization a lot of money.
• Hacking can lead to loss of business for organizations that deal in finance such as PayPal. Ethical hacking puts them a step ahead of the cyber criminals who would otherwise lead to loss of business.

What is Cybercrime?

Cybercrime is the use of computers and networks to perform illegal activities such as spreading computer viruses, online bullying, performing unauthorized electronic fund transfers etc.  Most cybercrimes are committed through the internet. Some cybercrimes can also be carried out using mobile phones via SMS and online chatting applications.

Type of Cybercrime

• The following list presents the common types of cybercrimes:
• Computer fraud:Intentional deception for personal gain via the use of computer systems.
• Privacy violation:Exposing personal information such as email addresses, phone number, account details etc. on social media, websites etc.
• Identity Theft:Stealing personal information from somebody and impersonating that person.
• Sharing copyrighted files/information:This involves distributing copyright protected files such as eBooks and computer programs etc.
• Electronic funds transfer:This involves gaining an un-authorized access to bank computer networks and making illegal fund transfers.
• Electronic money laundering:This involves the use of computer to launder money.
• ATM Fraud:This involves intercepting ATM card details such as account number and PIN numbers. These details are then used to withdraw funds from the intercepted accounts.
• Denial of Service Attacks:This involves the use of computers in multiple locations to attack servers with a view of shutting them down.
• Spam:Sending unauthorized emails. These emails usually contain advertisements.

what is hacking

WHAT IS HACKING

There are many definitions of hacking. In this article, we will define hacking as identifying weakness in computer systems and/or networks and exploiting the weaknesses to gain access. An example of hacking is using by passing the login algorithm to gain access to a system. A hacker is a person who finds and exploits weakness in computer systems and/or networks to gain access. Hackers are usually skilled computer programmers with knowledge of computer security.


MOBLIE PHONES HACKING

Phone hacking is the practice of manipulating or gaining unauthorized access to mobile phones - such as by intercepting telephone calls or accessing voicemail messages. When the unauthorized access is to the phone user's conversation, it is more commonly referred to as phone tapping.
Phone hacking is the practice of manipulating or gaining unauthorized access to mobile phones - such as by intercepting telephone calls or accessing voicemail messages. When the unauthorized access is to the phone user's conversation, it is more commonly referred to as phone tapping.

ETHICAL HACKER(WHITE HAT)
Ethical Hacker (White hat):A hacker who gains access to systems with a view to fix the identified weaknesses. They may also perform penetration testing and vulnerability assessments.

CRACKER(BLACK HAT)

Cracker (Black hat):A hacker who gains unauthorized access to computer systems for personal gain. The intent is usually to steal corporate data, violate privacy rights, transfer funds from bank accounts etc.

GREY HAT

Grey hat:A hacker who is in between ethical and black hat hackers. He/she breaks into computer systems without authority with a view to identify weaknesses and reveal them to the system owner.

HACKIVIST

Hacktivist:A hacker who use hacking to send social, religious, and political etc. messages. This is usually done by hijacking websites and leaving the message on the hijacked website.