Search results
Results from the WOW.Com Content Network
SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. [3] [4] They are built using the Merkle–Damgård construction, from a one-way compression function itself built using the Davies–Meyer structure from a specialized block cipher.
SHA-2: A family of two similar hash functions, with different block sizes, known as SHA-256 and SHA-512. They differ in the word size; SHA-256 uses 32-bit words where SHA-512 uses 64-bit words. There are also truncated versions of each standard, known as SHA-224, SHA-384, SHA-512/224 and SHA-512/256. These were also designed by the NSA.
md5sum is specific to systems that use GNU coreutils or a clone such as BusyBox.On FreeBSD and OpenBSD the utilities are called md5, sha1, sha256, and sha512.These versions offer slightly different options and features.
A 32-bit hashed integer is transcribed by successively indexing the table with the value of each byte of the plain text integer and XORing the loaded values together (again, the starting value can be the identity value or a random seed). The natural extension to 64-bit integers is by use of a table of 2 8 ×8 64-bit random numbers.
SHA-2 basically consists of two hash algorithms: SHA-256 and SHA-512. SHA-224 is a variant of SHA-256 with different starting values and truncated output. SHA-384 and the lesser-known SHA-512/224 and SHA-512/256 are all variants of SHA-512. SHA-512 is more secure than SHA-256 and is commonly faster than SHA-256 on 64-bit machines such as AMD64.
SHA-256: 256 bits Merkle–Damgård construction: SHA-384: 384 bits Merkle–Damgård construction: SHA-512: 512 bits Merkle–Damgård construction: SHA-3 (subset of Keccak) arbitrary sponge function: Skein: arbitrary Unique Block Iteration: Snefru: 128 or 256 bits hash Spectral Hash: 512 bits wide-pipe Merkle–Damgård construction Streebog ...
The salt and hash are then stored in the database. To later test if a password a user enters is correct, the same process can be performed on it (appending that user's salt to the password and calculating the resultant hash): if the result does not match the stored hash, it could not have been the correct password that was entered.
However, fingerprints based on SHA-256 and other hash functions with long output lengths are more likely to be truncated than (relatively short) MD5 or SHA-1 fingerprints. In situations where fingerprint length must be minimized at all costs, fingerprint security can be boosted by increasing the cost of calculating the fingerprint.