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Cryptographic weaknesses were discovered in SHA-1, and the standard was no longer approved for most cryptographic uses after 2010. 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.
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.
The following tables compare general and technical information for a number of cryptographic hash functions. See the individual functions' articles for further information.
SHA-1 160-bit (obsolete) SHA-2 available in 224, 256, 384, and 512-bit variants; HMAC keyed hash; PBKDF2 Key derivation function (RFC 2898) Digital signature standards
Algorithm and variant Output size (bits) Internal state size (bits) Block size (bits) Rounds Operations Security against collision attacks (bits) Security against length extension attacks
The commonly used SHA2 hashing algorithm is not memory-hard. SHA2 is designed to be extremely lightweight so it can run on lightweight devices (e.g. smart cards). [19] This means PBKDF2 is very weak for password storage, as commodity SHA-2 hashing hardware that can perform trillions of hashes per second is easily procured. [20] [21]
Table compares implementations of block ciphers. Block ciphers are defined as being deterministic and operating on a set number of bits (termed a block) using a symmetric key. Each block cipher can be broken up into the possible key sizes and block cipher modes it can be run with.
TLS 1.0 (deprecated) TLS 1.1 (deprecated) TLS 1.2 TLS 1.3 EV certificate SHA-2 certificate ECDSA certificate BEAST CRIME POODLE (SSLv3) RC4 FREAK Logjam Protocol selection by user Microsoft Internet Explorer Mobile [n 20] 7–9 Windows Phone 7, 7.5, 7.8: Disabled by default [57] Yes Yes No [citation needed] No [citation needed] No No [citation ...