# SHA1 vs SHA2 vs SHA256 – What’s the Technical Difference?

## Secure Hash Algorithms: SHA1 vs SHA2 and SHA1 vs SHA256

Learn what separates SHA1 vs SHA2 vs SHA256 to keep your data safe and secure. Find out which algorithm works best for you in this easy-to-follow guide!

SHA (Secure Hash Algorithm) is a family of cryptographic hash functions designed by the National Security Agency (NSA) and published by the NIST (National Institute of Standards and Technology).

Hash algorithms are one of the most powerful tools used for safeguarding private information. These algorithms transform a given string of data (such as a password or filename) into a fixed length “hash” that may be used to check the authenticity of the original data without storing it.

Hash algorithms are used in various industry verticals including finance, healthcare, government sites, and others. The SHA is a popular and well-respected hashing algorithm, which has different variants. But what does SHA mean and how are its variants different from each other?

In this article, we’ll dive deep into the SHA and its different variants (SHA1 vs SHA2 vs SHA256) along with their features. But before that, let’s get to know what a hashing algorithm is:

## What is a Hashing Algorithm?

The term “hash” or “digest” refers to the output of a hashing algorithm, which is a mathematical function that takes an input (or “message”) and produces a fixed-length string of characters. It’s crucial to remember that if you constantly use the same input, you’ll always get the same hash, but if you ever modify it, you’ll get an entirely different hash.

Another property of the hashing algorithms is it’s computationally infeasible to recreate the original input from its hash value. This means that the hashing algorithm can be used to check for input tampering if the original input and the hash are available.

Several typical uses for hashing algorithms include storing passwords, creating digital security certificate signatures, and verifying the integrity of content/codes or files.

A user’s password is hashed, and the resulting hash is kept in the server when a password is set. When the user subsequently attempts login, the server will hash the given password and check it against the previously saved hash. If it matches, users are given access to their accounts; otherwise, they are denied.

## What is SHA?

As mentioned, SHA (Secure Hash Algorithm) — a family of cryptographic hashing algorithms was developed by NSA and published by the NIST. The primary purpose of SHA is to ensure the integrity and authenticity of digital data by generating a unique, fixed-length hash value for a given input. The hash value is a digital representation of the input data and is used to verify that the data has not been tampered with or altered.

There are several versions of the SHA algorithm, including SHA-1, SHA-2, and SHA-3. Each version has a different level of security and produces a hash value of a different length. SHA-1, for example, produces a 160-bit hash value, while SHA-2 produces hash values of varying lengths, including 224, 256, 384, and 512 bits. SHA-3 is the latest version and uses a different algorithm called Keccak.

We’ll go into greater depth in terms of SHA-1, SHA-2, and SHA-256, and compare them against each other with differences to help you pick the right one. Overall, SHA is an important aspect of modern data security and is considered to be a secure and reliable method for protecting sensitive information.

## Why are SHA Algorithms Different from Others?

SHA was designed as a hashing method and not for encrypting and decrypting. It generates a one-way hash of data that can be used to check the data’s authenticity. Data encryption methods like AES, RSA, and Blowfish scramble information before sending it across a network or storing it on a disc to make it unreadable.

SHA algorithms are different from other hashing algorithms in several ways:

**Development:**SHA algorithms were developed by NSA and published by NIST, while other hashing algorithms may have been developed by different organizations or individuals.**Hash length:**SHA algorithms produce hash values of varying lengths depending on the version. For example, SHA-1 produces a 160-bit hash value, while SHA-2 produces hash values of varying lengths, including 224, 256, 384, and 512 bits.**Algorithm:**The latest version of SHA is SHA-3 which uses a different algorithm called Keccak and is not based on the same mathematical principles as SHA-1 and SHA-2. This makes it more secure against certain types of attacks.**Security:**SHA algorithms are designed to be more secure than other hashing algorithms. For example, SHA-1 was considered a secure algorithm for many years, but it has been found to be vulnerable to collisions and is no longer considered secure for use in new systems, while SHA-2 and SHA-3 are considered more secure.**Usages:**SHA algorithms are widely used in a variety of security applications, such as digital signatures, password storage, and data integrity, while other hashing algorithms may have more specific use cases.**One-way function:**SHA algorithms are one-way functions, meaning that it’s not possible to reconstruct the input data from the hash value. Also, it’s computationally infeasible to find two different inputs to produce the same hash value.

## What Determines the Security Strength of SHA algorithms?

The security strength of SHA algorithms is determined by their bit length, with longer bit lengths providing stronger security. For example, SHA-1 has a 160-bit output while SHA-256 has a 256-bit output. The longer the bit length, the more possible output combinations and the more difficult it is to find a collision.

Despite its widespread adoption and use, several security dangers are involved in using SHA. One of the most serious is the chance of collisions where two distinct inputs provide the same hash. If an attacker is able to generate the same hash for a genuine and malicious input, they can trick systems into thinking it’s the real input to avoid detection.

Since SHA-1 is vulnerable to collision attacks, it’s no longer recommended as a safe hashing algorithm. In a nutshell, the more susceptible an algorithm is to collisions, the less secure it is. Additionally, the algorithms are designed to be resistant to certain types of attacks, such as preimage and other attacks.

## What are the Different Versions of SHA with Examples?

There are several versions of the Secure Hash Algorithm (SHA) that include:

**SHA-0:**This was the first version of the SHA algorithm, but it was quickly replaced due to a significant vulnerability that made it insecure. The series then started with SHA-1, released two years after SHA-0.**SHA-1:**This is the first version of the SHA algorithm and was published in 1995. It produces a 160-bit hash.**SHA-1 example:**The string “password” when passed through the SHA-1 algorithm will produce the hash value of “5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8”.**SHA-2:**This is the second version of the SHA algorithm and was published in 2001. It includes several variations with different hash sizes including SHA-224, SHA-256, SHA-384, and SHA-512.**SHA-256 Example:**The string “password”, when passed through the SHA-256 algorithm, will produce the hash “*5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8*“.**SHA-3:**This is the third version of the SHA algorithm and was published in 2015. It includes several variations with different hash sizes, including SHA3-224, SHA3-256, SHA3-384, and SHA3-512.**SHA-3 example**, the string “password” when passed through the SHA3-256 algorithm, will produce the hash “*b109f3bbbc244eb82441917ed06d618b9008dd09b3befd1b5e07394c706a8bb980b1d7785e5976ec049b46df5f13*”.

## What Are the Differences Between SHA1, SHA2, and SHA256?

SHA1 vs SHA2 vs SHA256 are hashing algorithms used widely in practice for data encryption. Different hashing algorithms can generate different hashes, or “fingerprints,” of a file or communication. In this way, only the hash value of a file or message must be stored to ensure that it remains unchanged from its original state.

But how do SHA-1, SHA-2, and SHA-256 differ from one another?

Put simply, the primary distinction between SHA-1 and SHA-2 is the hash length. Further, SHA256 is part of SHA2. Compared to the longer and more sophisticated hashes generated by SHA-2 and SHA-256, SHA-1 is the simpler hashing algorithm.

As of this writing, the most recent and improved SHA version is SHA-3, which we’ll discuss some other time. In this table, we will examine the similarities and differences between SHA-1, SHA-2, and SHA-256.

### What is the Difference Between SHA1 vs SHA2

SHA-1 and SHA-2 belong to separate families of hashing algorithms and were introduced by NIST. SHA-1 was released in 1995 and made to generate a unique hash out of a file or message in a safe and trustworthy manner.

SHA-2 is a collection of six hashing algorithms namely SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-256. With a bigger hash size and a more complicated internal structure, these algorithms were developed as an upgrade over SHA-1.

Some key differences between the two are:

**Bit length:**SHA-1 produces a 160-bit hash value, while SHA-2 includes several versions with different bit lengths, including SHA-224, SHA-256, SHA-384, and SHA-512, which produce hash values of 224, 256, 384, and 512 bits, respectively.**Security:**SHA-1 has been found to be vulnerable to collision attacks and is considered less secure than the SHA-2 versions. SHA-2 is considered more secure than SHA-1 and is still widely used today.**Purpose:**SHA-1 was primarily used for digital signature verification and public key infrastructure (PKI) while the SHA-2 family is intended to be used in digital signature and certificate validation, data integrity, and other security applications where collision resistance is required.**Design:**SHA-1 is based on the Merkle-Damgard construction method while SHA-2 is based on the Davies-Meyer construction method, which is more complex and offers resistance to collision and preimage attacks.

Ultimately, the most notable distinction between SHA-1 and SHA-2 is that the latter is a more recent and robust hashing algorithm. It’s important to note that, as technology and cryptographic research evolve, the security of all cryptographic algorithms can be weakened by new attack methods. Therefore, it’s important to regularly re-evaluate the choice of algorithm and update it if necessary.

### What is the Difference Between SHA1 vs SHA256

The SHA-2 family includes SHA-256 as one of its algorithms. Its goal was to improve upon the security offered by SHA-1, and its implementation reflects the same. With SHA-256, the resulting hash value is 256 bits long, hence the name. The SHA-1 hash generates a 160-bit value; this is a twofold increase. SSL certificate authorities typically use this method as the gold standard for certificate authentication.

Collisions (where two different bits of data yield the same hash) and preimage attacks are harder to pull off against SHA-256 thanks to its bigger hash size . Additionally, this makes it more challenging to locate a pair of data sources that provide the same hash. More importantly, SHA256 is the standard hashing algorithm employed by blockchain systems.

Here are some key differences between SHA-1 vs SHA-256:

**Bit length:**SHA-1 produces a 160-bit hash value, while SHA-256 produces a 256-bit hash value.**Security:**SHA-1 has been found to be vulnerable to collision attacks and is considered less secure than SHA-256. SHA-256 is considered more secure than SHA-1 and is still widely used today.**Purpose:**SHA-1 is intended for digital signature and PKI verifications while SHA-256 is intended for digital signature and certificate validation, data integrity, and other security measures.**Design:**SHA-1 is based on the Merkle-Damgard while SHA-256 is based on the Davies-Meyer, which is complex and is more resistant to collision and preimage attacks.

When compared to its predecessor, SHA-256 produces a hash that is more difficult to compromise.

### What is the Difference Between SHA2 vs SHA256

Let’s clear up the ambiguity between the various SHA-2 algorithms and take a look at how SHA 2 and SHA-256 compare.

For starters, SHA-256 hash is part of the SHA-2 family of cryptographic functions that also includes SHA-224, SHA-384, SHA-512, SHA-512/224, and SHA-512/256. These algorithms generate a unique fixed-size digital signature for a message or data file.

Here are the key differences between the two:

**Bit length:**As mentioned, SHA-2 is a family of hash algorithms and each produces different bit lengths and hash values of 224, 256, 384, and 512 bits. SHA-256 is one specific version of the SHA-2 that produces a 256-bit hash value.**Security:**SHA-2 is considered more secure and is widely used today. The different bit lengths of the SHA-2 family provide different levels of security, with longer bit lengths providing stronger security.**Purpose:**Both SHA-2 & SHA-256 have certificate validation, data integrity, and other security applications.**Design:**SHA-2 & SHA-256 are based on the Davies-Meyer method, which is more complex and offers better resistance to collision and other attacks.

## The Difference Between SHA1 vs SHA2 vs SHA256

SHA1 | SHA2 | SHA256 |
---|---|---|

First introduced in 1995 | First introduced in 2001 | Introduced together with SHA-2 family |

Upgraded version of SHA-0 (1993) | Upgraded version of SHA1 (1995) | One of the algorithms within the SHA-2 family |

Generates a 160-bits (20-byte) hash value | It is set of six different algorithms (SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-512/256) As a result; it can generate hash values of 224, 256, 384 or 512 bits | Generates a 256-bit hash |

No longer considered secure due to the increased risk of collisions and preimage attacks. | More secure than SHA-1 | More resistant to collisions and preimage attacks than SHA-1 |

Used for digital signature verification and PKI | Digital signature and certificate validation, data integrity, security applications | Digital signature and certificate validation, data integrity, security applications |

Based on Merkle-Damgard | Based on Davies-Meyer | Based on Davies-Meyer |

## Future of SHA and Potential Replacements

SHA-3 is considered to be more secure than SHA-1 and SHA-2, but it has its own vulnerabilities. As the field of cryptography continues to evolve, new hashing algorithms may be developed that provide even higher levels of security.

Some potential replacements for SHA-3 include the BLAKE3 algorithm, which is designed to be faster and more secure than SHA-3. Also, the Argon2 algorithm is designed to resist attacks that exploit parallelism.

## Final Thoughts on SHA1 vs SHA2 vs SHA256

In summary, we discussed the SHA algorithms and why it’s important to understand the differences between SHA1 vs SHA2 vs SHA256 when it comes to secure data encryption. SHA2 and its derivatives, such as SHA256, offer better defense against assaults than the older and less secure SHA1 algorithm.

For the highest security, SHA256 or higher SHA versions are suggested for data encryption (Learn Hashing vs Encryption). Keep in mind that technology is always advancing, so it’s wise to always be on the lookout for the most recent and greatest encryption methods. Ultimately, your organization’s needs and the desired level of security will determine the best-fit algorithm.

## Frequently Asked Questions

### 1. Are SHA1 and SHA256 the same?

No, SHA1 and SHA256 are two separate algorithms for creating a safe hash. While both SHA1 and SHA256 can be used as cryptographic hash functions, these algorithms differ in output sizes and internal structures. One can generate a 160-bit hash value with SHA1 and a 256-bit hash value with SHA256. Additionally, since SHA1 and SHA-256 are not identical, the same input may generate different hash outputs when processed by the two algorithms.

### 2. Which is better, SHA1 or SHA256?

SHA256 is more secure than SHA1 because it uses a greater hash value and a more complex algorithm. In addition, SHA256 is thought to be more secure in the face of any undiscovered cryptographic threats in the future. Due to these factors, SHA256 has replaced SHA1 as the standard for cryptographic hashing.

### 3. Why is SHA-1 no longer secure?

Because of flaws in its collision resistance, SHA-1 is no longer trusted as a secure hashing algorithm. In 2005, scientists discovered that a hash collision could occur when two files generated an identical SHA-1 hash. Due to this vulnerability, an attacker may be able to overcome security measures by creating a malicious file with the same hash as a genuine file. Given these flaws, SHA-1 has been phased out in favor of more secure algorithms like SHA-256.

### 4. Is SHA-2 still used?

Yes, SHA-2 is extensively used and trusted for digital signatures, SSL/TLS, and virtual private networks (VPNs) are only some of the places where these algorithms are utilized because they are seen as more secure than SHA-1.

### 5. Why is SHA 256 called 256?

SHA 256 generates a 256-bit hash value that’s why its name includes 256. This means that the hash value generated by the algorithm is always 256 bits long (32 bytes). Any modification to the input data will result in a new hash value, as the hash value is a one-of-a-kind representation of the data. A bigger hash number such as 256 bits is deemed more secure than a lower value such as 160 bits since it increases the algorithm’s security level.