In web development (most commonly PHP/MySQL), the two most common hashes are SHA-1 and MD5.
Windows application developers have access to a wider array of hashes, including SHA-1, MD5, SHA356, and more.
hash function is technique used in message authentication it is attached to the message for security purpose
MD5
This really depends on which password you mean. Most user passwords aren't so much decoded as they are hashed through alorithms such as MD5 and the result compared to a stored hash for the password. If the hashes match, Linux concludes the password is correct. Passwords are done this way as checksum hashes can't be reversed. They are assymetrical, meaning running a hash through the same algorithm merely results in another hash, not the password. This is a very secure way to store passwords.
SHA-1
During login to any account authentication is used. In authentication the user password is matched with the password in the database.
MD5 and SHA
Username/ password
no
We never store passwords in a password field. If we did that, anyone with access to the database would have access to all the passwords. Instead, we store the output from a one-way cryptographic hashing function. That is, when a user creates a password, we store the hash value generated from that password via the hashing function. When the user subsequently enters their password in order to log on, the hash value generated by the entered password is compared with the stored hash value. If the two hash values match exactly then the correct password was entered. Being one-way, it is not possible to determine the password from the hash value, even if we know the precise implementation details of the hash function employed to create the hash value. This is the safest way to store passwords; we simply need to ensure that the same hash function that was used to generate the hash is also used to validate the user's password at logon. Cryptographic hashes can vary in length depending on which function was used to generate the hash value. Typical values are 128-bit, 160-bit, 256-bit and 512-bit, thus a fixed-length binary field of the required length would be suitable for storing the hash values.
You're talking about password entry. For that you will need a one-way cryptographic hashing function. The hashing function converts a user's name and password into a hash value which can be openly stored on disk. Being a one-way function, even if an intruder knows the hash values, it is not possible for them to determine which user name and password combination was used to generate which hash value other than by brute force. The most widely used cryptographic hash functions are SHA-1 (Secure Hash algorithm 1) and MD5 (named after the Merkle-Damgård construction upon which it is based). However, SHA-1 implementations are being dropped due to well-funded intrusions which suggest it is no longer secure. It has since been replaced by SHA-2 and SHA-3.
The minimum requirement's support for user identification and authentication is the use of a screen name or alias and a password. A secret question may also be used in support of the alias and password as a system for double checking identity.
Hashing is an algorithm (hash function) to convert a string of characters into a fixed sized text using mathematical functions. The file to be hashed is known as “input” the algorithm used in known as ”hash function” and output is called “Hash Value”, some people call hash value as message digest. Hash value is the value that dictates what exactly in this file and always produces hexadecimal value. more on :networkingmania