Difference between SHA1 and SHA256

SHA1 and SHA256 are hash functions used in cryptographic processes to provide integrity and security for various applications. Both belong to the Secure Hash Algorithm family, even though they truly have distinct security degrees, output sizes, and use cases. SHA1 was designed back in 1993 and was used with high applicability in digital signatures and SSL/TLS certificates, but it has been deprecated due to known vulnerabilities that permit collision attacks. SHA256 is an element of the SHA-2 family, introduced in 2001, with a larger 256-bit hash and providing enhanced security, it is quite reliable for most modern cryptographic needs, such as blockchain and secure communications. This paper compares SHA1 vs. SHA256 by giving their key features, advantages, disadvantages, and use cases that best fit your application when choosing the right hash function.

What is SHA1 (Secure Hash Algorithm 1)?

SHA1 for Secure Hash Algorithm 1, is a cryptographic hash function designed by the NSA back in the year 1993. It creates a 160-bit (20-byte) hash value usually displayed as a 40-character hexadecimal number. SHA1 found heavy usage in securing digital signatures, certificates, and integrity of data. The general use of SHA1 notwithstanding, the algorithm suffers from some critical security options: principally, the risk of collision attacks in which two different inputs result in the same hash value. Due to these weaknesses, SHA1 has been deprecated and is no longer recommended in secure applications. More robust algorithms, like SHA256, have taken the place of SHA1.

Example :

Data : Geeksforgeeks
SHA1 : bc7623b7a94ed3d8feaffaf7580df3eca4f5f5ca

Advantages of SHA1

• Fast Computation: Computation-wise, SHA1 is not as intensive. Thus, processing it is faster compared to new algorithms like SHA256. This makes it suitable for old legacy systems and applications that have performance constraints.

• Widespread Support: For many years, SHA1 was the standard; hence, it is supported across a variety of platforms, making it compatible with many systems and software.

Disadvantages of SHA1

• Security Vulnerabilities: SHA1 suffers from collision attacks in that two input strings of dissimilar content result in the same hash value output. This exposes the insecurity of the data and digital signatures.

• Deprecation: Having the inherent weaknesses, SHA1 has been deprecated by various organizations and is not considered secure anymore. Modern applications moved to more secure algorithms like SHA256.

• Obsolescence: Every SHA1 in SSL/TLS certificates is close to insignificance today, owing to non-support by major browsers and platforms.

What is SHA256?

SHA256 is an acronym for Secure Hash Algorithm 256. It is a cryptographically safe hash function that produces a 256-bit (32-byte) hash value. It was first published in 2001. It is part of the SHA-2 family developed by the NSA. It's extremely safe compared to SHA1. Collision resistance is the ability of the algorithm, such that it is computationally infeasible to find two different input strings having the same hash value. Due to its very high security, SHA256 finds itself in secure communications and digital signatures aside blockchain technology. This, however, comes at a slightly higher cost compared to SHA1 in terms of computational power and storage. Its reliability keeps it as the go-to for applications where data integrity and security are paramount. Nevertheless, SHA256 is considered secure for modern cryptographic needs and acts to benchmark the protection of sensitive information across different industries.

Example :

Data : Geeksforgeeks
SHA256 : e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855

Advantages of SHA256

• High Security: SHA256 has high collision and pre-image resistance; hence, it is appropriate for high-security applications.
• Wide Adoption: It is an industrially accepted standard in secure hashing, applied in digital signatures, SSL/TLS certificates, and blockchain technology.
• Long-term: So far, SHA256 remains safe, with no insecurity found. Thus, it's reliable for long-term apps and future-proof systems.

Disadvantages of SHA256

• Slower Computation: More processing power and time are required to compute SHA256 compared to SHA1. Therefore, this may have an overall performance impact in cases where resources are at a premium.
• Larger Hash Size: Its hash output is 256-bit, and it requires more storage and bandwidth that may be important in any cases where efficiency becomes an issue.
• More Resources: This increase in computational demand can strain low-powered devices or systems handling large-scale data processing.

Difference Between SHA1 and SHA256

Conclusion

SHA1 and SHA256 are members of the cryptographic hash functions family, where they actually satisfy different security requirements. SHA1, developed in 1993, has expired as the standard of digital signature and data integrity, as it is prone to a collision attack. In contrast, SHA256 is a member of the SHA-2 function family, proposed in 2001. Since its resultant hash size is large and it is strong against attacks, it is provided with stronger security. Although SHA256 consumes more computational resources and storage, its strength makes it fit for modern cryptographic applications. With regard to secure systems and future-proof ones, SHA256 is recommended for data integrity and protection against emerging threats.

Why is SHA1 deprecated?

SHA1 is deprecated due to known collision vulnerabilities that allow attackers to generate the same hash for different inputs, compromising data integrity.

Can SHA256 be cracked?

As of now, SHA256 is considered secure, with no practical collision attacks that could compromise its integrity.

Which is faster: SHA1 or SHA256?

SHA1 is faster but less secure. SHA256 is slower but offers significantly better security.

Where is SHA256 commonly used?

SHA256 is commonly used in blockchain technology, SSL/TLS certificates, digital signatures, and other secure communication protocols.