Sunday, September 6, 2015

How do I reset a lost administrative password?



By default the first user's account is an administrative account, so if the UI is prompting you for a password it's probably that person's user password. If the user doesn't remember their password you need to reset it. To do this you need to boot into recovery mode.
Boot up the machine, and after the BIOS screen, hold down the left Shift key. You will then be prompted by a menu that looks something like this:



I've noticed on some systems that timing when to hit the left Shift key can be tricky, sometimes I miss it and need to try it again.

Hit the down arrow until you select the 2nd entry from the top (the one with the recovery mode in the description) and then hit Enter.
Now you should see this menu:


Using the arrow keys scroll down to either root and then hit Enter.
You should now see a root prompt, something like this:
root@ubuntu:~#
At this stage you should have a read-only filesystem. You have to remount it with write permissions:
mount -rw -o remount /
Now we can set the user's password with the passwd command. (In this example I will use jorge as the example, you need to substitute whatever the user's username is):
root@ubuntu:~# passwd jorge
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
root@ubuntu:~#
by: scriptsandcodes ./#Pinoydeveloper
Type in what you want the new password to be at the prompt. After it's successful reboot the machine and the user will be able to log in with their new password.

  • Recovery Mode documentation
  • Lost password documentation

There is concern about this being a security vulnerability. It is not. You need to have physical access to the machine to do this. If someone has physical access to your PC, they could do far worse than change a password. When it comes to physical access, the battle for security is lost. Be wary of who you let on your PC.
Even setting a root password will not be successful, as one can simply boot with init being /bin/sh and have full root access. Again, given physical access, anyone with computer knowledge can do ANYTHING to your computer.


source: #AskUbuntu

Saturday, August 29, 2015

Cryptography

Cryptography?cryp·tog·ra·phykripˈtäɡrəfē/nounnoun: cryptographyCryptography or cryptology; from Greek κρυπτός...

Posted by Bitcoins Philippines on Monday, August 24, 2015


Cryptography or cryptology; from Greek κρυπτός kryptós, "hidden, secret"; and γράφειν graphein, "writing", or -λογία -logia, "study", respectively is the practice and study of techniques for secure communication in the presence of third parties (called adversaries). More generally, it is about constructing and analyzing protocols that block adversaries; various aspects in information security such as data confidentiality, data integrity, authentication, and non-repudiation are central to modern cryptography. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, and electrical engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce.


Cryptography prior to the modern age was effectively synonymous with encryption, the conversion of information from a readable state to apparent nonsense. The originator of an encrypted message shared the decoding technique needed to recover the original information only with intended recipients, thereby precluding unwanted persons from doing the same. Since World War I and the advent of the computer, the methods used to carry out cryptology have become increasingly complex and its application more widespread.


Modern cryptography is heavily based on mathematical theory and computer science practice; cryptographic algorithms are designed around computational hardness assumptions, making such algorithms hard to break in practice by any adversary. It is theoretically possible to break such a system, but it is infeasible to do so by any known practical means. These schemes are therefore termed computationally secure; theoretical advances, e.g., improvements in integer factorization algorithms, and faster computing technology require these solutions to be continually adapted. There exist information-theoretically secure schemes that provably cannot be broken even with unlimited computing power—an example is the one-time pad—but these schemes are more difficult to implement than the best theoretically breakable but computationally secure mechanisms.


The growth of cryptographic technology has raised a number of legal issues in the information age. Cryptography's potential for use as a tool for espionage and sedition has led many governments to classify it as a weapon and to limit or even prohibit its use and export. In some jurisdictions where the use of cryptography is legal, laws permit investigators to compel the disclosure of encryption keys for documents relevant to an investigation. Cryptography also plays a major role in digital rights management and piracy of digital media.


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History of cryptography

Cryptography, the use of codes and ciphers to protect secrets, began thousands of years ago. Until recent decades, it has been the story of what might be called classic cryptography — that is, of methods of encryption that use pen and paper, or perhaps simple mechanical aids. In the early 20th century, the invention of complex mechanical and electromechanical machines, such as the Enigma rotor machine, provided more sophisticated and efficient means of encryption; and the subsequent introduction of electronics and computing has allowed elaborate schemes of still greater complexity, most of which are entirely unsuited to pen and paper.


The development of cryptography has been paralleled by the development of cryptanalysis — the "breaking" of codes and ciphers. The discovery and application, early on, of frequency analysis to the reading of encrypted communications has, on occasion, altered the course of history. Thus the Zimmermann Telegram triggered the United States' entry into World War I; and Allied reading of Nazi Germany's ciphers shortened World War II, in some evaluations by as much as two years.


Until the 1970s, secure cryptography was largely the preserve of governments. Two events have since brought it squarely into the public domain: the creation of a public encryption standard (DES), and the invention of public-key cryptography.




soon to be update....

source: History of cryptography

Cryptography?cryp·tog·ra·phykripˈtäɡrəfē/nounnoun: cryptographyCryptography or cryptology; from Greek κρυπτός...

Posted by Bitcoins Philippines on Monday, August 24, 2015

Monday, August 24, 2015

Top 10 Programming-Language Latest Reviews

Open Source is the Future of the computer science world!


On Wednesday, the popular coding website GitHub shared a graph that gives a closer look at the popularity of different programming languages used on its code sharing website that lets anyone edit, store, and collaborate on software code. Since its launch in 2008, GitHub saw various programming languages picking up momentum, as shown in the graph below.

An insight into what GitHub is…
GitHub is a web-based repository that operates on the functionality of a 'Git,' which is strictly a command-line tool. With 10 Million users as of today, the platform has become the primary source of housing open source software that is free of cost available to the world at large.
A look at the picture of programming trends on GitHub over recent years is actually a look at how the computer world is evolving.

Top 10 Programming Languages

Here are the Top 10 Programming Languages on GitHub today:

  • JavaScript
  • Java
  • Ruby
  • PHP
  • Python
  • CSS
  • C++
  • C#
  • C
  • HTML


  • Yes, Java programming language topped the race. There was a time when Java was most likely to be used by big banks and other enterprise companies that build very private stuff.

    However, GitHub's data shows that Java grew more than any other programming language since 2008 and is being as a forefront of languages used to build open source software.
    Java's rise is also due to growing Android popularity, as Google made Java the primary language for developing applications on Android smart devices.
    Java is followed by Ruby, PHP, Python, and C#.
    The rank is calculated by a GitHub project called Linguist, which listed languages by their adoption in public and private repositories, excluding forks.
    However, these are the list of popular languages represented by GitHub; What, according to you, should be the most popular programming language? Let us know in the comments below.

    A New Open Source Programming Language developed by Facebook

    HACK - A New Open Source Programming Language developed by Facebook
    Facebook just released a new programming language called 'HACK', designed to build complex websites and other software quickly and without many flaws. The company has already migrated almost all of its PHP-based social networking site to HACK over the last year, but it has nothing to do with Hacking.

    When Social Networking website Facebook was started 10 years ago, it was coded in PHP by Mark Zuckerberg and team, but as the company grew, PHP Programming platform became difficult to manage and bug-free.

    Thus, Hack was born! Facebook Team decides to develop a new programming language that could combine elements of static-type programming languages such as C or C++ with dynamic-type languages like PHP, now called "HACK Programming Language".

    "Hack has deep roots in PHP. In fact, most PHP files are already valid Hack files." Facebook said, "We have also added many new features that we believe will help make developers more productive."

    HACK is a new version of PHP, requires Facebook’s HHVM (Hip Hop Virtual Machine) which is designed to execute programs written in Hack and PHP. The top 20 open source frameworks on Github run on HHVM.
    HACK - A New Open Source Programming Language developed by Facebook
    "Traditionally, dynamically typed languages allow for rapid development, but sacrifice the ability to catch errors early and introspect code quickly, particularly on larger codebases." Facebook posted on its engineering blog.

    So Hack Programming Language offers a lot of potential for developers, enabling them to program faster and be able to catch errors more easily, among other things. "Conversely, statically typed languages provide more of a safety net, but often at the cost of quick iteration. We believed there had to be a sweet spot."

    Beta code is open source and now available at Hacklang.org and you can also get Hack programming language tutorials from website to learn this new language. 

    "This is just the first step, and we are dedicated to continuing to evolve this software to make development even easier for both our own engineers and the broader community." The public release is not just to encourage developers, but also to quickly spot errors in Hack.

    HACK CODE GEN: Facebook Open-Sources Code That Writes Code

    Hack Codegen - Facebook Open-Sources Code That Writes Code
    Good news for Open Source Lovers!

    Facebook has open-sourced Hack Codegen – its library for automatically generating Hack code, allowing outside developers to automate some of their routine work while developing large programs.

    HACK is the Facebook's own programming language designed to build complex web sites and other software quickly and without many flaws.

    HACK programming language is developed for HipHop Virtual Machine (HHVM) – an open-source virtual machine designed to execute programs written in Hack and PHP. The top 20 open source frameworks on Github run on HHVM.

    Also Read: Top 10 Popular Programming Languages used on GitHub

    Sunday, August 16, 2015

    MIME content transfer encoding.

    Content-Transfer-Encoding[edit] In June 1992, MIME (RFC 1341, since made obsolete by RFC 2045) defined a set of methods for representing binary data in formats other than ASCII text format. The content-transfer-encoding: MIME header has 2-sided significance: It indicates whether or not a binary-to-text encoding scheme has been used on top of the original encoding as specified within the Content-Type header: If such a binary-to-text encoding method has been used, it states which one. If not, it provides a descriptive label for the format of content, with respect to the presence of 8-bit or binary content. The RFC and the IANA's list of transfer encodings define the values shown below, which are not case sensitive. Note that '7bit', '8bit', and 'binary' mean that no binary-to-text encoding on top of the original encoding was used. In these cases, the header is actually redundant for the email client to decode the message body, but it may still be useful as an indicator of what type of object is being sent. Values 'quoted-printable' and 'base64' tell the email client that a binary-to-text encoding scheme was used and that appropriate initial decoding is necessary before the message can be read with its original encoding (e.g. UTF-8). Suitable for use with normal SMTP: 7bit – up to 998 octets per line of the code range 1..127 with CR and LF (codes 13 and 10 respectively) only allowed to appear as part of a CRLF line ending. This is the default value. quoted-printable – used to encode arbitrary octet sequences into a form that satisfies the rules of 7bit. Designed to be efficient and mostly human readable when used for text data consisting primarily of US-ASCII characters but also containing a small proportion of bytes with values outside that range. base64 – used to encode arbitrary octet sequences into a form that satisfies the rules of 7bit. Designed to be efficient for non-text 8 bit and binary data. Sometimes used for text data that frequently uses non-US-ASCII characters. Suitable for use with SMTP servers that support the 8BITMIME SMTP extension (RFC 6152): 8bit – up to 998 octets per line with CR and LF (codes 13 and 10 respectively) only allowed to appear as part of a CRLF line ending. Suitable for use with SMTP servers that support the BINARYMIME SMTP extension (RFC 3030): binary – any sequence of octets. There is no encoding defined which is explicitly designed for sending arbitrary binary data through SMTP transports with the 8BITMIME extension. Thus, if BINARYMIME isn't supported, base64 or quoted-printable (with their associated inefficiency) are sometimes still useful. This restriction does not apply to other uses of MIME such as Web Services with MIME attachments or MTOM.

    Radix

    In mathematical numeral systems, the radix or base is the number of unique digits, including zero, used to represent numbers in a positional numeral system. For example, for the decimal system (the most common system in use today) the radix is ten, because it uses the ten digits from 0 through 9. In any positional numeral system (except unary, where the radix is 1), the number x and its base y are conventionally written as (x)_y, although for base ten the subscript is usually assumed and not written, as it is the most common way to express value. For example, (100)_{10} (in the decimal system) represents the number one hundred, whilst (100)_2 (in the binary system with base 2) represents the number four.[1] we will update it soon...

    ASCII

    ASCII (Listeni/ˈæski/ ass-kee), abbreviated from American Standard Code for Information Interchange,[1] is a character-encoding scheme (the IANA prefers the name US-ASCII[2]). ASCII codes represent text in computers, communications equipment, and other devices that use text. Most modern character-encoding schemes are based on ASCII, though they support many additional characters. ASCII was the most common character encoding on the World Wide Web until December 2007, when it was surpassed by UTF-8, which includes ASCII as a subset.[3][4][5] ASCII developed from telegraphic codes. Its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on the ASCII standard began on October 6, 1960, with the first meeting of the American Standards Association's (ASA) X3.2 subcommittee. The first edition of the standard was published during 1963,[6][7] a major revision during 1967,[8][9] and the most recent update during 1986.[10] Compared to earlier telegraph codes, the proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists, and added features for devices other than teleprinters. Originally based on the English alphabet, ASCII encodes 128 specified characters into seven-bit binary integers as shown by the ASCII chart on the right.[11] The characters encoded are numbers 0 to 9, lowercase letters a to z, uppercase letters A to Z, basic punctuation symbols, control codes that originated with Teletype machines, and a space. For example, lowercase j would become binary 1101010 and decimal 106. ASCII includes definitions for 128 characters: 33 are non-printing control characters (many now obsolete)[12] that affect how text and space are processed[13] and 95 printable characters, including the space (which is considered an invisible graphic[14][15]:223). we will update it soon....

    Binary data

    Binary data is data whose unit can take on only two possible states, traditionally termed 0 and +1 in accordance with the binary numeral system and Boolean algebra. Forms and interpretations of binary data come in different technical and scientific fields. Such two-valued unit can be termed: "bit" (binary digit) in computer science, "truth value" in mathematical logic and related domains, "binary variable" in statistics. we will update it soon...

    Binary-to-text encoding

    A binary-to-text encoding is encoding of data in plain text. More precisely, it is an encoding of binary data in a sequence of characters. These encodings are necessary for transmission of data when the channel does not allow binary data (such as email or NNTP) or is not 8-bit clean. PGP documentation (RFC 4880) uses the term ASCII armor for binary-to-text encoding when referring to Radix-64.

    What is the Base64?

    Base64 is a group of similar binary-to-text encoding schemes that represent binary data in an ASCII string format by translating it into a radix-64 representation. The term Base64 originates from a specific MIME content transfer encoding. Base64 encoding schemes are commonly used when there is a need to encode binary data that needs to be stored and transferred over media that is designed to deal with textual data. This is to ensure that the data remains intact without modification during transport. Base64 is commonly used in a number of applications, including email via MIME, and storing complex data in XML. we will update it soon...