256-bit encryption is much secure than 128-bit. A 256-bit encryption key means there are 2256 possible combinations compared to the 128-bit key which has 2128 possible combinations a hacker would have tried to break the encryption. In simple terms, 256-bit key takes 14 rounds of AES compared to 10 AES rounds of 128-bit key for each data block. It is still impossible to break or brute-force a 256–bit encryption algorithm.
Sebastine Take On How Encryption Works
Encryption is the process of taking plain text, like a text message or email, and scrambling it into an unreadable format — called “ciphertext.” This helps protect the confidentiality of digital data either stored on computer systems or transmitted through a network like an internet.
When the intended recipient accesses the message, the information is translated back to its original form. This is called decryption.
To unlock the message, both the sender and the recipient have to use a “secret” encryption key — a collection of algorithms that scramble and unscramble data back to a readable format
Symmetric encryption
Symmetric encryption is a type of encryption where only one key (a secret key) is used to both encrypt and decrypt electronic information. The entities communicating via symmetric encryption must exchange the key so that it can be used in the decryption process. This encryption method differs from asymmetric encryption where a pair of keys, one public and one private, is used to encrypt and decrypt messages.
By using symmetric encryption algorithms, data is converted to a form that cannot be understood by anyone who does not possess the secret key to decrypt it. Once the intended recipient who possesses the key has the message, the algorithm reverses its action so that the message is returned to its original and understandable form. The secret key that the sender and recipient both use could be a specific password/code or it can be a random string of letters or numbers that have been generated by a secure random number generator (RNG). For banking-grade encryption, the symmetric keys must be created using an RNG that is certified according to industry standards, such as FIPS 140-2.
There are two types of symmetric encryption algorithms:
- Block algorithms. Set lengths of bits are encrypted in blocks of electronic data with the use of a specific secret key. As the data is being encrypted, the system holds the data in its memory as it waits for complete blocks.
- Stream algorithms. Data is encrypted as it streams instead of being retained in the system’s memory.
The secret key here can either be a mix of words and numbers, letters, or numbers that are applied to a specific message. Symmetric encryption is mainly preferred with these digital certificates because it is not only fast but also easily implemented by hardware-it can also easily handle bulk data.
Perhaps the only downside of using this encryption model is the key. It uses just one key, meaning that if anyone exposes the key, then hackers can access the complete information.
Asymmetric encryption
This refers to two keys out of one is to encrypt the message while the private key is meant to decode the information.
The asymmetric key is also used for exchanging symmetric keys. Asymmetric key takes more computational time because the verification and functions of both sides are involved. It may slow down the process while asymmetric key saves time in the encryption process.
Advanced Encryption Standard:
The Advanced Encryption Standard (AES) is a symmetric block cipher chosen by the U.S. government to protect classified information.
AES is implemented in software and hardware throughout the world to encrypt sensitive data. It is essential for government computer security, cybersecurity, and electronic data protection.
The National Institute of Standards and Technology (NIST) started the development of AES in 1997 when it announced the need for an alternative to the Data Encryption Standard (DES), which was starting to become vulnerable to brute-force attacks.
What are the features of AES?
NIST specified the new AES algorithm must be a block cipher capable of handling 128-bit blocks, using keys sized at 128, 192, and 256 bits.
Other criteria for being chosen as the next AES algorithm included the following:
- Security. Competing algorithms were to be judged on their ability to resist attack as compared to other submitted ciphers. Security strength was to be considered the most important factor in the competition.
- Cost. Intended to be released on a global, nonexclusive and royalty-free basis, the candidate algorithms were to be evaluated on computational and memory efficiency.
- Implementation. Factors to be considered included the algorithm’s flexibility, suitability for hardware or software implementation, and overall simplicity.
Why is Data Encryption Essential?
Businesses and government organizations that possess consumer and employee data must use, at minimum, AES encryption, as well as other tools and methods such as two-factor authentication to ensure only authorized users can access this data. Organizations should do all they can to protect consumers’ information online. As the Software Alliance puts it, “Digital security is becoming increasingly important to protect us as we bank, as we shop, and as we communicate. And at the core of that security lies encryption.”
128 and 256-bits are just key lengths, and in as much as website security is concerned, these key lengths are not directly proportional to your website’s security. Instead, website security is determined by your server capabilities and technologies that have been put in place. These keys are, however, still crucial.
Difference between 128-bit vs. 256-bit encryption:
- If you see the beneath table, it takes 31 x 1056years to crack it compare to 128-bit encryption.
- 256-bit key takes 14 rounds of AES compare to 10 AES rounds in 128-bit key.
- The speed issue for ISP will be solved with a 256-bit key.
- With the advancement of computational power, 128-bit is easy to crack compared to 256-bit key.
- Most certificate authorities have moved to 256-bit encryption nowadays.
When you buy a 128-bit encryption SSL Certificate, it means that the certificate can encrypt secure connections up to 128-bits. The same pertains to a 256-bit certificate.
The length of the key here (either 128 or 256-bits) is a representation of how resistant the encrypted connections are to be guessing.
| Key Size | Average Time to Crack |
| 56-bit | 399 Seconds |
| 128-bit | 1.02 x 1018 years |
| 192-bit | 1.872 x 1037 years |
| 256-bit | 3.31 x 1056 years |
From the table above, you notice that 128-bit may take too long to crack while 256-bit will take lots of decades to crack.
That is a lot of numbers that even if the hacker dedicated all his life guessing each of them, he would not complete guessing all of them. Even for the current quantum computers, it would still take very many decades to try all these combinations and get the right one.
Besides, SSL Certificates have a very short lifespan and Google is even pushing for the lifespan to be slashed down from 825 days to just 397 days. That means the renewals ratio will be at a high rate equipped with modern algorithms so even before a hacker could crack the first one.
Sebastine Final Word
Both certificates, which offer 128-bit and 256-bit encryption, provide high-level security that is very difficult to crack. However, the option that most people prefer is going to the certificates which provide 256-bit encryption because they take even more time to guess and are the hardest to break.