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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.
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 attacker having physical access to a computer can, for example, install a hardware or a software keylogger, a bus-mastering device capturing memory or install any other malicious hardware or software, allowing the attacker to capture unencrypted data (including encryption keys and passwords) or to decrypt encrypted data using captured ...
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.
The original Password Safe was built on Bruce Schneier's Blowfish encryption algorithm. Rony Shapiro implemented Twofish encryption along with other improvements to the 3.xx series of Password Safe. [7] The keys are derived using an equivalent of PBKDF2 with SHA-256 and a configurable number of iterations, currently set at 2048. [8] [9]
A password to encrypt a document restricts opening and viewing it. This is possible in all Microsoft Office applications. Since Office 2007, they are hard to break if a sufficiently complex password was chosen. [citation needed] If the password can be determined through social engineering, the underlying cipher is not important.
To generate the table, we choose a random set of initial passwords from P, compute chains of some fixed length k for each one, and store only the first and last password in each chain. The first password is called the starting point and the last one is called the endpoint. In the example chain above, "aaaaaa" would be the starting point and ...
The encryption process consists of updating the state with four round functions over 10 rounds. The four round functions are SubBytes (SB), ShiftColumns (SC), MixRows (MR) and AddRoundKey (AK). During each round the new state is computed as S = A K ∘ M R ∘ S C ∘ S B ( S ) {\displaystyle S=AK\circ MR\circ SC\circ SB(S)} .