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الحلقة السادسة عشر من راديو اسأل مطور, في هذه الحلقة نناقش مهارة جديدة من مهارات المطور و هي مهارة التعامل مع الكود القديم. نقدم بعض النصائح في كيفية التعامل مع الكود القديم و أيضاً كيف تستلم كود من مطور آخر بحيث تسهل على نفسك كثير من التعب الذي قد يحدث في المستقبل. أيضاً بعض الأدوات التي قد تساعدك.
Welcome to the 16th episode of Ask Developer Podcast, in this episode we discuss the topic of Legacy Code, and how to handle and handover code bases, also tools and best practices that can help.
Join our facebook page
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EP16 - Developer Skills - Working With Legacy Code

اللقاء الأسبوعي الرابع عشر لمجموعة اسال مطور, في هذا الاسبوع نناقش موضوع أمن المعلومات و كيف يمكنك كمطور تثقيف نفسك عن المخاطر و المشاكل الأمنية المختلفة و كيفية مواجهتها.
لمشاهدة اللقاء على يوتيوب
http://www.youtube.com/watch?v=7RlYk5suvMM
لمزيد من التفاصيل
http://www.askdeveloper.com/2013/06/ask-developer-hangout-14-software.html

اشترك في اللقاءات عن طريق متابعتنا على صفحتنا
http://facebook.com/askdeveloper

EP19 - Ask Developer Hangout - Week 14 - Software Security

Introduction
Waterfall classic software development lifecycle
Iterative Approach.
2- Agile Software Development
History of Agile
Principles (for full list http://agilemanifesto.org/principles.html)
Satisfy the customer through early and continuous delivery of valuable software
Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.
Business people and developers must work together daily throughout the project
Promoting self organizing team
At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.
Pros & Cons
Famous Processes
Scrum
XP (eXtreme Programming)
Common Practices
Pair Programming
Test Driven Development (TDD)
Small Teams
Daily meetings

EP24 - Ask Developer Hangout - Week 12 - Agile Software Development

اللقاء الأسبوعي السادس و الثلاثون لمجموعة اسأل مطور, في هذا الأسبوع نناقش أهم التغيرات و التطورات في مجال تطوير البرمجيات التي حدثت في عام 2013
Looking back to 2013 what happened in the developers world, what technologies, practices, wins and losses

EP27 - Ask Developer Hangout - Week 36 - Software Development Events In 2013

الحلقة الثلاثون من راديو اسأل مطور, في هذا الأسبوع نطرح دور الDevOps في تطوير المؤسسات

What is the role of DevOps?
 "Automate All Things"
A role currently related to Online Services.
The principle of self-serve IT
Streamline and Automate Operation tasks
 Monitoring & Alerting
 Deployment
 Scaling up & down
 OS\Platforms upgrades, patches ... etc
 Building internal platforms to facilitate many IT related jobs
  Creating virtual machines
  Assigning DNS's
  Configuring load balancers \ software load balancers
  Self-Serve deployment
Technologies 
 All virtual machine automation software
 Chef http://www.getchef.com/
 Puppet http://puppetlabs.com/
 Salt http://docs.saltstack.com/index.html
 Graphite http://graphite.wikidot.com/

EP30 - DevOps

اللقاء الأسبوعي الثامن و الثلاثون, في هذا الأسبوع يحدثنا المهندس طارق عمرو عن الMachine Learning.

Slides for the presentation
http://tarekamr.com/slides/datascience

EP31 - Ask Developer Hangout - Week 38 - Machine Learning With Tarek Amr

الحلقة 32, في حلقة هذا الأسبوع نناقش تطور برمجة الويب و نطرح بعض الاختلافات بين الويب قديماً و حالياً و التحديات المختلفة.

	The simplicity and complexity of the web.
	It used to be just HTML
		Then Javascript
		And CSS
		And million libraries and frameworks.
	Markup as a way for building UIs.
		WPF
	Server side vs client side (the loop)
	Web technologies in non-web scenarios:
		FirefoxOS
		NodeJS Desktop applications (using Node-Webkit https://github.com/rogerwang/node-webkit)
			Example: https://www.mapbox.com/tilemill/ I've used this desktop application and liked it, and a week later discovered that it's a NodeJS app.
	Browsers as Operating Systems:
		Chromebooks
		FirefoxOS
	Single-page applications (SPA) as a way to blur the lines between web applications and desktop applications.
		Google's big push for AngluarJS is part of making web application replace desktop applications.

EP32 - Web Development Evolution

هل محبين و متابعين التكنولوجيا في المنطقة العربية يجب عليهم التحدث و الكتابة بالعربية؟ هل من يود تعلم التكنولوجيا في المنطقة العربية عليه أن يجيد اللغة الانجليزية و يتجه للمصادر الأجنبية؟
Should Arabic technology enthusiasts and workers speak and write in Arabic? should people who wish to learn about IT go for Arabic or English resources?

EP33 - Arabic Or English

ِAsk Developer Podcast الحلقة 34, في هذه الحلقة نناقش موضوع ال Freelancing و كيف تبدأ فيه و ما هو و مميزاته و عيوبه و بعض النصائح من التجارب الشخصية.
What is freelancing? 
Comparing freelancing to regular job
How to find freelancing opportunity? 
How to handle clients? 
How to put your name out there? 
Places To look for freelancing opportunities. 
 Rentacoder
 Guru

Video version
https://www.youtube.com/watch?v=k-562HWe1N4


EP34 - Freelancing

الحلقة السادسة و الثلاثون من راديو اسأل مطور, نناقش في هذا الأسبوع أهمية نظم حفظ و تنظيم الكود Source Control و نقارن بين أنواعها المختلفة و نتكلم باستفاضة عن Git

What is source control
Why do I need Source Control
Source control absence from official CS curriculum is a disaster
Source control can be as important as If Else statements
Important for individuals. Vital for teams
Types of Source Control Systems
	Centralized (Traditional)
		CVS
		SVN - Subversion.
		TFS
	Distributed
		Git
		Mercurial 
Awesome Git Features
	Stash
	Branching with no overhead
	Local Commits (never lose a thing)
	Rewriting History (rebasing)
Git vs GitHub
	GitLab
	Bitbucket
Using GitHub in non-programming projects


EP36 - Source Control And Git

Introduction
What is a package?
What is a Package Manager?
Why Do we need Package Manager?
Pros and Cons
	Pros
		Break your code into sharable components.
		Reduce build times.
		Easy to find well-made packages to speed up development.
		Resolving versioning in a clean way.
	Cons
		Sometimes packages don't play well together
		Too many package managers with very little differences
Examples
	Ruby Gems (was that the first one?)
	Python Pip
	NuGet
	NPM
	apt-get
	OneGet
	Chocoloty
	Bower
	Yum
	pacman


EP38 - Package Managers

	• What's wrong with the world as it is today?
		○ Gatekeepers and Walled Gardens 
		○ The Master Switch by Tim Wu
			▪ Tim Wu is the one who coined the Net Neutrality term.
			▪ This book tells the story of how every communication medium starts a revolution that upsets the order, then eventually it gets controlled. The same thing could happen to the Internet.
	• Bitcoin
		○ Is this about money, or about technology
		○ Is this about the technology or bitcoin, or the technology of distributed money.
		○ How Bitcoin works. Video.
		○ Bitcoin mining in plain English.
	• Blockchain
		○ permissionless distributed database based on the bitcoin protocol that maintains a continuously growing list of data records hardened against tampering and revision, even by its operators. The initial and most widely known application of block chain technology is the public ledger of transactions for bitcoin, which has been the inspiration for similar implementations often known as altchains
		○ Trustless transactions
		○ Simple explanation of how Blockchain works.
	• Distributed hash tables
		○ class of a decentralized distributed system that provides a lookup service similar to a hash table
	• Git
		○ Git GPG Signature
	• BitTorrent
	• IPFS: Inter-Planetary File System
		○ Intro to IPFS 
		○ IPFS: Why We Must Distribute the Web (Video)
		○ How to Use IPFS to fix NPM
		○ HTTP is obsolete. It's time for the distributed permanent web
			▪ This page is actually served via IPFS
It covers important points: how IPFS does mutable data, how it does human-readable URLs.

EP45 - A little bit about Bitcoin

Information Security
 1. Introduction
  ○ Security by obscurity
   § Steganography
    □ Hiding data inside another form of data, like using non-used bits in image to hide a message
     § Cool, but not practical.
     § Disadvantages
      ◊ Algorithm secrecy vs. key secrecy
  ○ Cryptography is everywhere and yet if done right, you can barely see it.
  ○ Goals: 
   § Confidentiality
    □ Secrets stay secret.
   § Integrity
    □ Data is not tampered with.
   § Non-Repudiation
    □ No party can deny sending messages.
   § Authentication
    □ Each party can ensure that the sender is what they expect.
  ○ Cryptography
   § Hashing
   § Encryption
   § Signing
   § Protocols
  ○ Random Number Generators
   § Extremely important, almost all encryption/hashing strength is affected by how random the random number generator is.
   § Don't use simple random number, use a cryptographic random number generator with a sophisticated source of entropy.
   § Pseudorandom number generator
   § Dual_EC_DRBG random generator backdoor
 2. Body
  ○ Hashing (one Way)
   § Properties
    □ Fixed length output no matter what size the input was
    □ Very easy to compute the hash of a given message, however very hard to compute from a hash the corresponding input.
    □ Mathematically infeasible to generate a message that has a given hash
    □ Any modification to a message produces a completely different hash that has no relationship to the original message's hash.
    □ It is mathematically infeasible to find two messages with the same hash. Hash Collision
   § Hashing Functions
    □ Provides data integrity, however lacks authentication
    □ Examples
     ® MD5 
      ◊ Considered Insecure
     ® Secure Hash Family SHA-X, Sha-1, Sha-2 [Sha256, Sha512], Sha-3
      ◊ Sha-1 is considered insecure.
      ◊ Sha-1, Sha-2 designed by NSA
      ◊ Sha-3 is not designed by NSA, Competition winner.
    □ Attacks
     ® Brute force
      ◊ CPU's are getting faster and cheaper every day.
      ◊ GPU's are getting faster and cheaper every day.
      ◊ Special Hash calculating hardware is becoming more available especially with the BitCoin push.
     ® Rainbow table attacks
      ◊ Pre-Calculated tables where you can reverse lookup a hash to a value
      ◊ Try www.crackstation.net
   § Hash Message Authentication Codes (HMAC)
    □ Adds authentication to integrity
    □ Can be used with all previous algorithms, HMACMD5, HMACShA1, HMAC256 … etc.
   § Salted Hash
    □ Adds random salt to mitigate rainbow table
    □ Salts are unique per record, and not a secret.
   § Password Based Key Derivation Function (PBKDF2)
    □ RSA Public Key Cryptographic Standard PKCS #5 Version 2.0
    □ Internet Engineering Task Force RFC 2898 Specification
     ® Adds a lot of iterations to slow it just enough to mitigate brute force (default 50,000 iterations)
     ® Adds random salt to mitigate rainbow table
    □ Disadvantage: It can be easily implemented with hardware which makes it vulnerable to bruteforce even with high number of iterations
   § Bcrypt
    □ Password Hashing function
    □ State of the art password hashing
   § Usages
    □ Integrity Check
Password Storage

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AskDeveloper Podcast

EP46 - AskDeveloper Podcast - Cryptography - Part 1 - Introduction and Hashing

الحلقة السابقة 
https://soundcloud.com/askdeveloper/ep46-askdeveloper-podcast-cryptography-part-1-introduction-and-hashing
○ Encryption (Two Ways)
   § Symmetric Encryption
    □ Same key both encrypts and decrypts the data.
    □ Very fast, yet exchanging key is tricky
    □ Very Algorithmic
    □ Examples
     ® DES Data Encryption Standard (BROKEN)
      ◊ Uses key of 56 bit length
     ® Triple DES (3DES)
      ◊ Uses three keys (or two unique keys) of 56 bit each
     ® AES Advanced Encryption Standard
      ◊ Uses keys of 128, 192 or 256 bits long
    □ Attacks
     ® Brute force
      ◊ Usually mitigated via increasing key length, as difficulty increases exponentially as key size increases, for example time to crack given a modern super computer.
      Key Size Time To Crack
      56 bits 399 seconds
      128 bits 1.02 * 1018 years
      192 bits 1.87 * 1037 years
      256 bits 3.31 * 1056 years
      ◊ Side-Channel Attacks
   § Asymmetric Encryption
    □ Key pairs have mathematical relationship
    □ Each one can decrypt messages encrypted by the other.
    □ Slow, but exchanging key is trivial
    □ Very Mathematical
    □ Anyone can know the Public Key
     ® The Public key can only be used to encrypt data
    □ The Private key is kept secret, and never leaves the recipient's side.
     ® The Private key can only be used to decrypt data
    □ Examples
     ® RSA (Rivest, Shamir and Adelman)
     ® The de-facto standard in the industry
     ® Public and Private keys are based on large Prime Numbers
   § Hybrid Encryption
    □ Uses both Symmetric and Asymmetric encryption at the same time.
    □ Goals:
     ® Use the performance of Symmetric Crypto 
     ® Convenience of sharing keys using Asymmetric Crypto
     ® HMAC for authentication.
    □ Steps: (Order is very important)
     ® Party 1 (Alice)
      1. Generates a random AES Session Key (32 bytes / 256 bits)
      2. Generates a random Initialization Vector (IV) (16 bytes / 128 bits)
      3. Encrypt the message to be sent using the AES Session Key & IV
      4. Calculate an HMAC of the encrypted message using the AES Session key
      5. Encrypt the AES Session Key using the Public Key of Party 2 (Bob) The recipient.
      6. Sends a packet of (Encrypted Message, Encrypted Session Key, Initialization Vector, and HMAC) to Bob
     ® Party 2 (Bob)
      1. Decrypts Session key using his Private Key
      2. Recalculates the HMAC of the encrypted message (Validates message integrity)
       } If HMAC check pass
        – Decrypts the message using the decrypted AES Session Key and Initialization Vector
       } Otherwise, rejects the message because of integrity check failure.


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EP47 - AskDeveloper Podcast - Cryptography - Part 2 - Encryption

○ Digital Signatures
   § Goal: verify Authenticity of a message.
   § Based on Asymmetric Cryptography.
   § Basic operations
    1. Public / Private keys generation (using some algorithm like RSA)
    2. Signing algorithm using the private key
    3. Signature verification algorithm using the corresponding public key
   i. Extending previous Example
    • Steps (Order is very important, bold stuff is the difference added to authenticate sender)
     ® Party 1 (Alice)
      1. Generates a random AES Session Key (32 bytes / 256 bits)
      2. Generates a random Initialization Vector (IV) (16 bytes / 128 bits)
      3. Encrypt the message to be sent using the AES Session Key & IV
      4. Calculate an HMAC of the encrypted message using the AES Session key
      5. Encrypt the AES Session Key using the Public Key of Party 2 (Bob) The recipient.
      6. Calculate Signature using the private signing key on the HMAC
      7. Sends a packet of (Encrypted Message, Encrypted Session Key, Initialization Vector, HMAC, and Signature) to Bob
     ® Party 2 (Bob)
      1. Decrypts Session key using his Private Key
      2. Recalculates the HMAC of the encrypted message (Validates message integrity)
       } If HMAC check pass
        – Verify digital signature using Alice Public Key
         w If signature verification pass
          w Decrypts the message using the decrypted AES Session Key and Initialization Vector
         w Otherwise, identity of the sender couldn't not be verified, reject message.
       } Otherwise, rejects the message because of integrity check failure.
    • Why Order matters?
     ® Timing Side-Channel Attacks
     ® Padding-Oracle Attack
     
  ○ Protocols
   § TLS/SSL
    • How TLS/SSL Works?
    • Mitigates against
     ® Man in the Middle Attacks
     ® Authentication, so the client can be sure it is talking to the correct destination.
   § Public Key Infrastructure (PKI)
    • Certificates aka X.509 Certificate (Sha-1 Signature Issues)
     ® A digitally signed file
     ® Identifies (Computer / User / Device)
     ® Has Public & Private Key, only the certificate owner has the Private Key.
     ® Has Expiration date
     ® Information about the CA that issued the cert 
     ® X.509 Extension Attributes (like Usage attribute)
     ® Revocation Information.
    • Certificate Authority (CA) (CNNIC, WoSign)
     ® Issues, signs and manages certificates.
     ® Famous certificate authorities (Verisign, GoDaddy, … etc).
    • Trust Chains
     ® CA's can delegate the signing job to subordinate CA's
      ◊ Root CA's signs an intermediate signing certificate to the subordinate CA
     ® The subordinate CA can then issue certificates
     ® To validate a certificate, the client validates the signatures of all the intermediate stages and make sure all of them are linked to a Trusted CA
    • Certificate Revocation Lists (CRL's)
     ® When a certificate is compromised (Private Key leaked) it will be published on the CRL, so each time the cert is validated, the CRL list is checked in case cert is revoked.
 3. Takeaways
 4. Books
  a. Understanding Cryptography: A Textbook for Students and Practitionershttps://www.amazon.com/Understanding-Cryptography-Textbook-Students-Practitioners/dp/3642041000


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AskDeveloper Podcast - 49 - Cryptography - Part 3 - Digital Signaures and Protocols

Welcome to the first episode of the AskDeveloper Podcast, in this episode Tamer Zaki & Mohamed Elsherif are discussing the Software Quality issues especially in the Egyptian technology market, and how to change the culture for companies and development teams to adopt the right methodologies and processes.

Our theme music is provided by www.podcastthemes.com

EP01 - AskDeveloper PodCast - Software Quality

Welcome to the third episode of the AskDeveloper Podcast, in this episode we switch gear to answer the hard question of "How to build a good team?" and we start by the first stage in building your team which is recruitment, we discuss different aspects and stages of the recruitment  like

Who is a good candidate?
Where to publish job posts and find candidates
Recruitment Process
Industry Hires
Collage Hires
Interviewing for Interviewees
Interviewing for interviewers
Book recommendation

EP03 - AskDeveloper - Team Building - Recruitment

الحلقة الرابعة عشر من راديو اسأل مطور, في هذه الحلقة نناقش موضوع الطرق الهندسية الحديثة في ادارة المشاريع البرمجية, و كيف تقدم هذه الطرق داخل بيئة عملك و ما هي الفوائد و التحديات التي يمكن تواجهها.
Welcome to the 14th episode of Ask Developer Podcast, in this episode we discuss the Agile Software Development and we give an example of Scrum, we also discuss some real world experiences and best practices.

Ask Developer

ibrahim Taha