How long would it take to crack AES 128?
With the right quantum computer, AES-128 would take about 2.61*10^12 years to crack, while AES-256 would take 2.29*10^32 years. For reference, the universe is currently about 1.38×10^10 years old, so cracking AES-128 with a quantum computer would take about 200 times longer than the universe has existed.
AES, which typically uses keys that are either 128 or 256 bits long, has never been broken, while DES can now be broken in a matter of hours, Moorcones says. AES is approved for sensitive U.S. government information that is not classified, he adds.
The EE Times points out that even using a supercomputer, a “brute force” attack would take one billion years to crack AES 128-bit encryption.
AES 256 is virtually impenetrable using brute-force methods. While a 56-bit DES key can be cracked in less than a day, AES would take billions of years to break using current computing technology. Hackers would be foolish to even attempt this type of attack. Nevertheless, no encryption system is entirely secure.
Even if you use Tianhe-2 (MilkyWay-2), the fastest supercomputer in the world, it will take millions of years to crack 256-bit AES encryption.
AES-128 is faster and more efficient and less likely to have a full attack developed against it (due to a stronger key schedule). AES-256 is more resistant to brute force attacks and is only weak against related key attacks (which should never happen anyway).
The AES-256 block cipher hasn't been cracked yet, but there have been various attempts against AES keys. The first key-recovery attack on full AES was published in 2011 by Andrey Bogdanov, Dmitry Khovratovich, and Christian Rechberger.
According to the Snowden documents, the NSA is doing research on whether a cryptographic attack based on tau statistic may help to break AES. At present, there is no known practical attack that would allow someone without knowledge of the key to read data encrypted by AES when correctly implemented.
It would take billions – yes, billions – of years for a supercomputer to crack even a 128-bit AES key. Quantum computers can break AES algorithms quicker, but, according to some sources, it would still take a quantum computer roughly six months to exhaust the possibilities of a 128-bit AES key.
AES-256, which has a key length of 256 bits, supports the largest bit size and is practically unbreakable by brute force based on current computing power, making it the strongest encryption standard. The following table shows that possible key combinations exponentially increase with the key size.
Can Supercomputers break AES?
There's simply no way, with today's technology, that AES-256 can be brute-force attacked.
No, AES-128 has not been broken by any means in any practical sense.
There isn't a single 512-bit symmetric key cipher in common public use. The whirlpool hash function, which is based on AES, returns a 512-bit digest, but that's not the same thing as a 512-bit AES cipher. The common comparison with RSA is that a 128 bit symmetric key corresponds to about 3000 bit RSA.
Security That's Virtually Unbreakable
“Military-grade” refers to AES-256 encryption. This standard was established in order to be in compliance with the Federal Information Processing Standards (FIPS) that govern the handling of sensitive data. It offers 128-bit block encryption via the use of cryptographic keys.
Military-grade encryption refers to AES-256.
Military-grade encryption refers to a specific encryption type – AES (Advanced Encryption Standard, or Rijndael) algorithm. This encryption method was established in 2001 by the U.S. National Institute of Standards and Technology (NIST).
In today's level of technology, it is still impossible to break or brute-force a 256-bit encryption algorithm. In fact, with the kind of computers currently available to the public it would take literally billions of years to break this type of encryption.
AES 256-bit encryption is the strongest and most robust encryption standard that is commercially available today. While it is theoretically true that AES 256-bit encryption is harder to crack than AES 128-bit encryption, AES 128-bit encryption has never been cracked.
Most of the updated algorithms being used are currently "secure enough" for the time being until quantum computing is developed further specifically for bruteforcing passwords or cracking hashes. At minimum it would take a month, or up to a year to crack a single "standard" strong password of constant computing.
So on our hypothetical machine, a 56-bit DES key would take, on average, 255/246.5=28.5≈362 seconds to find. Similarly, a 128-bit AES key would take 2127/246.5=280.5 seconds ≈255 (or approximately 36 quadrillion) years to find.
128-bit encryption is a data/file encryption technique that uses a 128-bit key to encrypt and decrypt data or files. It is one of the most secure encryption methods used in most modern encryption algorithms and technologies. 128-bit encryption is considered to be logically unbreakable.
How hard is it to crack 256 bit encryption?
In today's level of technology, it is still impossible to break or brute-force a 256-bit encryption algorithm. In fact, with the kind of computers currently available to the public it would take literally billions of years to break this type of encryption.
There are around 32 million seconds in a year. 32 million is 25 doublings. So if you can crack a 64-bit key in a second it will take a year for an 89-bit key (64 + 25). A million is 20 doublings, so an 109-bit key will take a million years.
