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RFC 7677, SCRAM-SHA-256 and SCRAM-SHA-256-PLUS: Simple Authentication and Security Layer (SASL) Mechanisms; RFC 7804, Salted Challenge Response HTTP Authentication Mechanism; RFC 8600, Using Extensible Messaging and Presence Protocol (XMPP) for Security Information Exchange; RFC 8621, The JSON Meta Application Protocol (JMAP) for Mail
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.
Typically, a unique salt is randomly generated for each password. The salt and the password (or its version after key stretching) are concatenated and fed to a cryptographic hash function, and the output hash value is then stored with the salt in a database. The salt does not need to be encrypted, because knowing the salt would not help the ...
An initialization vector (IV) or starting variable (SV) [5] is a block of bits that is used by several modes to randomize the encryption and hence to produce distinct ciphertexts even if the same plaintext is encrypted multiple times, without the need for a slower re-keying process. [citation needed]
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.
L is an optional label to be associated with the message (the label is the empty string by default and can be used to authenticate data without requiring encryption), PS is a byte string of k − m L e n − 2 ⋅ h L e n − 2 {\displaystyle k-\mathrm {mLen} -2\cdot \mathrm {hLen} -2} null-bytes.
In cryptanalysis and computer security, password cracking is the process of guessing passwords [1] protecting a computer system.A common approach (brute-force attack) is to repeatedly try guesses for the password and to check them against an available cryptographic hash of the password. [2]
The salt value is not secret and may be generated at random and stored with the password hash. A large salt value prevents precomputation attacks, including rainbow tables, by ensuring that each user's password is hashed uniquely. This means that two users with the same password will have different password hashes (assuming different salts are ...