SHA-256 stands for “Secure Hash Algorithm 256bit,” and SHA-1 stands for “Secure Hash Algorithm 1”, a cryptographic function designed by the United States National Security Agency is used in many different systems with many different uses. Both SHA-256 and SHA-1 are extremely similar hash functions, yet they are different too.

## Key Takeaways

- SHA-256 generates a 256-bit hash, while SHA-1 produces a 160-bit hash.
- SHA-256 is more secure than SHA-1 due to its longer hash and resistance to collision attacks.
- SHA-1 is faster than SHA-256, but its reduced security makes it unsuitable for modern applications.

**SHA-256 vs SHA-1**

SHA-256 is an algorithm which takes an input message and produces a 256-bit (32-byte) output called a hash, which is unique to that input message. SHA-1 is an older and less secure algorithm. It takes an input message and produces a 160-bit (20-byte) output called a hash.

SHA-256 is a cryptographic function that generates an almost impossible-to-predict string of characters based on the input.

Moreover, SHA-256 is a newer, stronger, more advanced algorithm that is used in many different systems with many different uses. However, SHA-256 is used by bitcoin miners.

SHA-1 is a cryptographic function that takes a message of any length as input and produces a 160-bit string.

Moreover, SHA-1 is an older and slower algorithm that has a very low-performance rate and is most used to store passwords because encryption is easier to crack.

**Comparison Table**

**Comparison Table**

Parameters of Comparison | SHA-256 | SHA-1 |
---|---|---|

Definition | SHA-25 is a cryptographic function with a newer, stronger, more advanced algorithm. | SHA-1 is a cryptographic function with an older algorithm. |

Performance Time | The time it takes to compute an SHA-256 hash value is far longer. | The time it takes to compute an SHA-1 hash value is less. |

Space | The SHA-256 algorithm requires much more space to store a hash value in memory or disk. | The SHA-1 algorithm requires less space to store a hash value in memory or on a disk. |

Speed | The SHA-256 algorithm’s performance is faster. | The SHA-1 algorithm’s performance is slower. |

Security | The SHA-256 algorithm has more security. | The SHA-1 algorithm has less security. |

**What is SHA-256?**

SHA-256 is used in Bitcoin transactions to verify transactions and generate the public key for each coin owner.

Moreover, SHA-256 can also be used in certain types of password authentication protocols when combined with another function to ensure that passwords are difficult to obtain by computer brute force attacks or other methods.

SHA-256 is used in Bitcoin mining, file verification in BitTorrent clients, strong authentication on some wireless networks, Cryptographic hashing for digital signatures, and password authentication in file transfer programs, such as FileZilla. For instance, When you log onto your bank’s website to set up an account or transfer money between accounts, you are logging onto your bank’s server with a shared secret key that was generated with the help of SHA-256.

SHA-256 is a cryptographic function that generates an almost impossible-to-predict string of characters or hash based on the input function.

The SHA-256 algorithm requires much more space to store a hash value in memory or disk. Moreover, this affects how much room your network security system has to store a certain number of hashed values.

In some protocols, SHA-256 is called a hashing function rather than a hash function, and that is because SHA-256 is extremely fast and has very high security.

Moreover, SHA-256 is the default hash function in many programs and has proven itself over many years. Lots of internet services use SHA-256 for this purpose.

This includes OpenSSH, Apache web servers, MySQL databases, Tomcat, Postfix mail servers, and many others.

**What is SHA-1?**

SHA-1 was designed by the National Security Agency, which produces a 160-bit message digest for a given input message.

It is commonly used to verify data integrity, create a digital signature with a private key, and use public-key cryptography.

SHA-1 is an older algorithm with less security, space, and low performance that is not an encryption algorithm but only produces a message digest that can be used as part of various cryptographic algorithms and protocols that use hashing for security purposes.

However, SHA-1 is most used to store passwords because encryption is easier to crack.

An SHA-1 hash is found as a sequence of 40 hexadecimal digits, displayed in groups of four digits from left to right.

The first fourteen of these digits, representing the first 40 bits of the message, are the “message digest.”

The subsequent twenty digits represent a “protocol-specific message authentication code,” commonly called a “signature,” which cryptographically proves the identity of the SHA-1 implementation and the integrity of the message under the cryptographic hash function.

SHA-1 has been discovered to be vulnerable to attacks that can reduce its effective key length from 448 bits to as few as 256 bits. Although SHA-1 was later upgraded to use significantly larger keys, no known attack on any published hash function breaks the security of SHA-1 completely.

However, some known attacks yield significant reductions in the security of SHA-1. These so-called “collision attacks” are not directly related to the cryptographic weakness of SHA-1.

**Main Differences Between SHA-256 and SHA-1**

- SHA-256 is a cryptographic function with a newer, stronger, more advanced algorithm, whereas SHA-1 is a cryptographic function with an older algorithm.
- The SHA-256 algorithm requires a lot more space to store a hash value in memory or on a disk, whereas, The SHA-1 algorithm requires less space to store a hash value in memory or on a disk.
- The performance time it takes to compute an SHA-256 hash value is far longer, whereas, The performance time it takes to compute an SHA-1 hash value is less.
- The SHA-256 algorithm’s performance is faster, whereas, The SHA-1 algorithm’s performance is slower.
- The SHA-256 algorithm has more security, whereas, The SHA-1 algorithm has less security.

**References**

- https://link.springer.com/chapter/10.1007/978-3-540-24654-1_13
- https://www.sciencedirect.com/science/article/pii/S0141933116300473
- https://ieeexplore.ieee.org/abstract/document/5491466/

Last Updated : 11 June, 2023

Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.