Education is broken — but this entrepreneur has a stunningly simple idea to fix it

A former hedge fund analyst pointed out a crippling flaw in the US education system during alive TED Talk in New York City in November.

Salman Khan, also a founder of the free education resource Khan Academy, says we force students to move ahead when they aren't ready.

But he has a solution.

"We shouldn't drag everyone around at the same pace," Khan told the audience. Instead, he says, we should take inspiration from martial arts teaching.

Suppose a student gets a 75% on a test, which is a passing grade. Khan says this means the student didn't learn 25% of the material, yet they're expected to move on to the next lesson with the rest of the class.

The problem with this, he says, is the next block of material builds on what the student was supposed to learn in the last lesson, and it's usually more difficult to pick up. So a student learns only 75% of the material, we can't expect that student to master the next section.

You can see how this effect could quickly snowball as a student works their way up through more advanced classes. If students don't master all of algebra, for example, they'll have significant knowledge gaps when trying learn calculus.

Khan says we assume they are bad at math, or born without the "math gene," and so they'll give up on the class.

In reality, they're not bad at math — they just didn't master the foundation material, he said.

Which is why Khan argues we shouldn't drag everyone through school at the same pace. The education system should work the same way as martial arts or mastering a musical instrument, he says: Practice your white belt skills until they're perfect, then move up to the yellow belt; practice the beginner piece until you nail it, then move on to the more advanced song; don't move onto calculus if you haven't mastered algebra and trigonometry.

A lot of research out there backs up Khan's idea. Students that don't move onto the next lesson until they master the first often perform better later in their education career than peers who are arbitrarily shoved along from grade to grade.

If we personalize the education experience for students instead of requiring them to move as a herd, then anyone "could become a physicist, or a cancer researcher, or a rocket scientist," Khan said.

Provided, of course, that they put in the work required to master all of the steps.

9 Mind-Blowing Inventions That You Did Not Know Were Made By Pakistanis

Pakistanis are pure genius... We just don't say it, we can prove it. Here is the list of some of the amazing inventions made by Pakistanis, followed/ practiced/ used by people around the globe.

1. Fertilizers With Non-Explosive Materials

Recently a Pakistani fertilizer company invented a new formula to make fertilizers that cannot be converted into bomb-making materials. Previously, fertilizers with ammonium nitrate, were easily converted into bomb-making ingredients.

2. Successful Brain-Silicon Chip Connection

Dr. Naweed Syed is the first scientist who managed to "connect brain cells to a silicon chip". This Pakistani helped the world achieve a great milestone. This discovery will significantly help in the research of integrating computers with the human brains in order to assist people monitor vital signs control artificial limbs, correct memory loss or vision impairment.

3. Sagar Veena

The Sagar Veena, use in classical music, was developed completely in Pakistan over the last 40 years by Raza Kazim at the Sanjannagar Institute, Lahore.

4. Human Development Index

Pakistani economist Mahbub ul Haq devised the Human Development Index in 1990 in order to move the focus of development economics to people centered policies from national income accounting.

5. Lavatory That Transforms Human Waste into Charcoal, Minerals, And Clean Water

Pakistani researcher at Loughborough University, Sohail Khan designed a  lavatory that converts human waste into biological charcoal, which can be burned, and clean water.

6. (c) Brain, One Of The First Computer Viruses

This virus was created by the Farooq Alvi Brothers in 1986 in Lahore, Pakistan to discourage piracy of the software they had made.

7. The Ommaya Reservoir

Developed by Ayub K. Ommaya, the Ommaya reservoir is a system used for injecting the medicines into the cerebrospinal fluid for treatment of patients with brain tumours.

8. Pleuroperitoneal Shunt, Endotracheal Tube

A Pakistani American doctor from Peshawar, Pakistan invented the Pleuroperitoneal Shunt and a Special Endotracheal Tube tube to supply oxygen during fiber-optic bronchoscopy in awake patients.

9. A Software Simulation To Reduce Death Rate In Bomb Blast

A Pakistani computer scientist, Zeeshan-ul-Hassan Usmani, has introduced a Software simulation based on blast forensics designed by that claims to reduce deaths (on average) by 12% and injuries by 7% merely by altering the way a group of people stand near an expected suicide bomber.

Cryptography - Famous Encryption Techniques

Brief Report

Encryption methods

1.     Symmetric vs. Asymmetric Encryption

There are two basic techniques for encrypting information: symmetric encryption (also called secret key encryption) and asymmetric encryption (also called public key encryption.)

Symmetric Encryption

Symmetric encryption is the oldest and best-known technique. A secret key, which can be a number, a word, or just a string of random letters, is applied to the text of a message to change the content in a particular way. This might be as simple as shifting each letter by a number of places in the alphabet. As long as both sender and recipient know the secret key, they can encrypt and decrypt all messages that use this key.

Asymmetric Encryption

The problem with secret keys is exchanging them over the Internet or a large network while preventing them from falling into the wrong hands. Anyone who knows the secret key can decrypt the message. One answer is asymmetric encryption, in which there are two related keys--a key pair. A public key is made freely available to anyone who might want to send you a message. A second, private key is kept secret, so that only you know it. 

Symmetric vs. Asymmetric

Symmetric	Asymmetric
Symmetric encryption uses the identical key to both encrypt and decrypt the data.	Asymmetric encryption uses two related keys (public and private) for data encryption and decryption.
Security risks.	Takes away the security risks.
Exposed key.	The private key is never exposed.
Much faster computationally than asymmetric algorithms as the encryption process is less complicated.	Little complicated than symmetric.
Key is transferred with encrypted data to decrypt data.	Public key is exposed and other user knows the private key.

2.     RSA (Rivest-Shamir-Adleman) - Asymmetric

RSA is a cryptosystem for public-key encryption, and is widely used for security sensitive data, particularly when being sent over an insecure network such as internet.

It is also known as asymmetric cryptography. It has two keys a public key and a private key. The public key can be shared with anyone whereas private key must be kept secret. When encrypting the message, it is raised to the power of the key, and divided with remainder by a fixed product of two primes. By repeating the process with the other key, the plaintext can be retrieved back.

3.     AES (Advanced Encryption Standard) - Symmetric

It is a software and hardware tool to encrypt and decrypt text using AES encryption algorithm. You can chose 128, 192 or 256-bit long key size for encryption and decryption.

AES comprises three block ciphers, AES-128, AES-192 and AES-256. Each cipher encrypts and decrypts data in blocks of 128 bits using cryptographic keys of 128, 192 and 256-bits, respectively. Symmetric or secret-key ciphers use the same key for encrypting and decrypting, so both the sender and the receiver must know and use the same secret key.

4.     RSA vs. AES

RSA is an asymmetric cipher. It is ideal for secure exchange of messages across an untrusted network, because the public key can be known by everyone - a message encrypted with the public key can only be decrypted by the private key. As such, if two parties know each other's public keys, they can exchange messages securely. This means that no secret information has to be transmitted - as long as authenticity and integrity are maintained you're safe. Thankfully, RSA provides a method of generating signatures on data, which help prove that it is authentic. Given a message signed by a private key, it is possible to verify that signature using the corresponding public key.

As a rule of thumb, you can only encrypt data as large as the RSA key length. So, if you've got a 4096-bit RSA key, you can only encrypt messages up to 4096 bits long. Not only that, but it's incredibly slow. RSA isn't designed as a full-speed data transport cipher. RSA is much slower.

AES is a symmetric block cipher, and is incredibly fast. The plaintext is split into chunks called blocks, and each block is encrypted in a chain. There are different ways of doing this, but a common one is called Cipher Block Chaining, or CBC for short. This allows for theoretically infinite message sizes. However, symmetric ciphers like AES require a secret key to be exchanged first. Unlike RSA, the shared key must remain unknown to attackers, so you have to provide authenticity, integrity, and secrecy. That's difficult to do directly.

References:

http://blog.atmel.com/2013/03/11/symmetric-vs-asymmetric-encryption-which-way-is-better/

https://support.microsoft.com/en-us/kb/246071

http://searchsecurity.techtarget.com/definition/Advanced-Encryption-Standard

https://www.boxcryptor.com/en/encryption