SHA1 vs. SHA2 vs. SHA256: Understanding the Difference

Comparing SHA1 vs. SHA2 – Which Is More Secure?

In this blog, we will talk about SHA1 vs. SHA2, as you might have seen them frequently used in your journey to understanding cybersecurity. SHA might remind you of the negative emotions from the World of Warcraft, the popular online game. If you are not an MMORPG gamer, you might think of SHA1 and SHA2 as hash algorithms. Though both analogies about SHA (Secure Hashing Algorithm) are correct, we will talk about the one that is based on hashing.

We want to make sure you’re at the correct place for the right kind of Hash, so we will go through what it means in cybersecurity terms.

What is Hashing?

The digital space was, is, or will never be safe as long as countless cyber criminals and hackers are lurking around and looking for ways to lure netizens and steal their data. Fortunately, users have started being on their toes and become alert of their digital footprints, taking extra care of their data security.

Thus, everyone using the Internet must consciously and consistently validate the legitimacy of each e-attribute. How, you ask? That is where Hashing comes into play!

Hashing defines a mathematical algorithm that employs cryptographic techniques to transform plaintext into a distinct ciphertext or text string. Let us take an example to understand hashing better.

Suppose your name is Sarah, and you must enter it into a website while keeping it confidential. Applying the hashing algorithm will transform your name into a unique string of text that only you can decrypt.

So Sarah will be converted to – 28e5481a80aa2bd18c8cf35d0495980a

Oftentimes, people mistake hashing for encryption. However, encryption is actually a two-way function, while hashing is just one-way. The key difference between encryption and hashing is that encryption can be reversed, while hashing cannot be reversed.

Let us give you an example of their applications for a better understanding.

Applications of Hashing

The banking sector makes practical use of hashing in one of its applications. Let’s say you have applied for a credit card and entered a password to access your account. Though you are using the bank’s server, it does not save your credentials in the system. Rather, it will run your password via a hashing function and saves the ‘hash’ as your password. So every time you log in to your account, it tallies the password you enter with the hash password it has saved in its system. When the two match, you get the authority to use your account.

Encryption is utilized to encrypt the data in transit, such as your credit card password, ensuring that it remains inaccessible to anyone during the data communication between the two servers.

So, hashing is used for:

Verifying the integrity of data
Authentication purposes
Storing confidential information.

Now that we know what hashing is and how it differs from encryption let us understand SHA in simple terms.

What is Meant by SHA?

SHA is an abbreviation for secure hashing algorithm. SHA (Secure Hash Algorithm) is a cryptographic algorithm used for hashing data and certificates. In SHA, each piece of information or data has a unique hash that does not match any other data, making duplicating it practically impossible. Furthermore, as the Hash depends on the generated out Hash (from the data), the final digital signature is also distinct.

SHA has two algorithm versions, typically used by the Public Key Infrastructure Market (PKI). They are SHA-1 and SHA-2. Let us discuss them briefly.

Developed by the U.S. Government SHA-1 and SHA-2 are two cryptographic versions of the SHA and results from the same algorithm. Despite that, these two have some technical differences that we will talk about now.

What is SHA-1?

SHA-1 is a cryptographic hash function that uses a 160-bit output represented by a 40-digit long hexadecimal number. The algorithm builds upon principles similar to those used in the design of the MD4 and MD5 hashing algorithms, which found application in the early 1990s. It generates a unique message of length <264 in blocks of 512 bits. Simply put, while computing a message digest, the algorithm processes a block of 512 bits in sequence. Distributed revision control systems such as Mercurial, Monotone, and Git also utilize this hash function.

What is SHA-2?

The U.S. designed SHA-2 as a cryptographic hash function. National Security Agency. While it works the same as SHA-1, it offers a higher security level. Made to eliminate the security shortcomings in the SHA-1 algorithm, it is a family of four hash functions, each having their own digest sizes: SHA-224, SHA-256, SHA-384, and SHA-512.

SHA-256 works on 32-bit, whereas SHA-512 works on 64-bit words, which is why both use different algorithms. However, organizations widely employ them to authenticate and sign digital security certificates like SSLs, Code Signing certificates, and documents.

Many people frequently use and compare the 256-bit with SHA-1. The reason is quite simple. The 224-bit variant is not robust enough to support publicly-trusted SSL certificates, while the 512-bit variant is not compatible with a wide range of software, making SHA256 the popular SHA2 algorithm.

What are the Differences between SHA1 vs. SHA2?

Although both the hash function algorithms sound similar, SHA-2 generates a longer hash. Not just that, there are more differences between the two versions. Let’s find out.

1. Algorithm for SHA1 and SHA2

While the two algorithms belong to the SHA group of cryptographic hash functions and have found their usage in the U.S. Government, SHA-2 is a safer hashing algorithm when compared to the SHA-1 hashing function. When discussing the SHA-1 algorithm, security vulnerabilities render it insecure. Consequently, users no longer utilize SHA-1-based certificates and intermediates.

2. Message Digest

SHA-1 generates a unique message of length <2^64 in blocks of 512-bit and comes up with a 160-bit message digest. By processing the blocks of 512 bits, it renders a 40-digit long hexadecimal number. It came into existence in order to solve security vulnerabilities. Meanwhile, SHA-2 processes messages in 512-bit blocks for the 224, 256, and 384 hash functions and 1,024 blocks for the SHA-512 algorithm.

3. Security

Between 2011 and 2015, the primary hashing algorithm in use was SHA-1. However, security vulnerabilities emerged during this time, leading to the adoption of SHA-2 as a means to address these issues. SHA-2 generates a longer hash and is therefore considered secure.

Also popular as SHA1 vs SHA256, let’s finish up with a side-by-side comparison of SHA1 vs. SHA2:

Type of Hash Function	SHA-1	SHA-2
Algorithm	SHA-1 is the oldest and primary hashing algorithm of the SHA family of hash functions	SHA-2 is a group of cryptographic hash functions that were developed as a substitute for the SHA-1 algorithm.
Relevance	SHA-1 is no longer a universally recognized hash function due to its security vulnerabilities.	SHA-2 is quite improved and is used for securing trust certificates.
Message Digest	SHA-1 generates a unique message of length <2^64 in blocks of 512-bit and comes up with a 160-bit message digest.	SHA-2 is a group of four hash functions, each having its own digest size: SHA-224, SHA-256, SHA-384, and SHA-512.
Application	This hash function is also employed in distributed revision control systems like Mercurial, Monotone, and Git.	This hash function is widely used to authenticate and sign digital security certificates like SSLs and Code Signing certificates and documents.

We hope the side-by-side comparison of both the hash function helped you better understand the concept of SHA-1 and SHA-2.

Get Hashed, Get Secured

Since the 1950s, hash algorithms have been in existence. However, the digital landscape has changed with the Internet becoming more and more accessible. Today, cyber-attacks have increased, and the need for hashing algorithms has also changed. The concept that was limited to user authentication and checking data integrity is now used for generating message digests and digital signatures, thereby securing the data.

We hope we have given a good insight into SHA1 vs. SHA2. So, if you are a stakeholder in this cybersecurity campaign, make sure you use these concepts to keep your user data safe and secure.