[permalink] [id link]
SHA-1 HMAC Generation. In cryptography, a hash-based message authentication code ( HMAC ) is a specific construction for calculating a message authentication code ( MAC ) involving a cryptographic hash function in combination with a secret cryptographic key.
from
Wikipedia
Some Related Sentences
SHA-1 and HMAC
Any cryptographic hash function, such as MD5 or SHA-1, may be used in the calculation of an HMAC ; the resulting MAC algorithm is termed HMAC-MD5 or HMAC-SHA1 accordingly.
The size of the output of HMAC is the same as that of the underlying hash function ( 128 or 160 bits in the case of MD5 or SHA-1, respectively ), although it can be truncated if desired.
In 2006, Jongsung Kim, Alex Biryukov, Bart Preneel, and Seokhie Hong showed how to distinguish HMAC with reduced versions of MD5 and SHA-1 or full versions of HAVAL, MD4, and SHA-0 from a random function or HMAC with a random function.
However, claims in 2006 ( Kim, Biryukov2, Preneel, Hong, " On the Security of HMAC and NMAC Based on HAVAL MD4 MD5 SHA-0 and SHA-1 ") cause some doubt over other MD5 applications as well.
* HMAC ( K, C ) = SHA1 ( K ⊕ 0x5c5c … ∥ SHA1 ( K ⊕ 0x3636 … ∥ C )) be an HMAC calculated with the SHA-1 cryptographic hash algorithm
SHA-1 and .
* < tt > Bitser </ tt >, a free Microsoft Windows application that calculates MD5, SHA-1 and SHA-256 sums for any given input file.
* < tt > Cobynsoft's Hash Calculator </ tt >, a free multi-file hash calculator for Windows that calculates MD5, SHA-1, SHA-256 and SHA-512 checksums.
*< tt > File Checksum Integrity Verifier ( FCIV )</ tt >, a command-prompt utility from Microsoft that computes and verifies MD5 or SHA-1 cryptographic hash values of files.
Some cryptographic hash functions, such as SHA-1, have even stronger uniformity guarantees than checksums or fingerprints, and thus can provide very good general-purpose hashing functions.
For example, MD5 and SHA-1 operate on 512-bit blocks.
Blocksize is 64 ( bytes ) when using one of the following hash functions: SHA-1, MD5, RIPEMD-128 / 160.
It is an improved version of RIPEMD, which in turn was based upon the design principles used in MD4, and is similar in performance to the more popular SHA-1.
RIPEMD-160 was designed in the open academic community, in contrast to the NSA-designed SHA-1 and SHA-2 algorithms.
On the other hand, RIPEMD-160 appears to be used somewhat less frequently than SHA-1, which may have caused it to be less scrutinized than SHA.
* Choose an approved cryptographic hash function H. In the original DSS, H was always SHA-1, but the stronger SHA-2 hash functions are approved for use in the current DSS.
* The MD5-SHA-1 combination in the digitally signed element was replaced with a single hash negotiated during handshake, defaults to SHA-1.
* The pseudorandom function splits the input data in half and processes each one with a different hashing algorithm ( MD5 and SHA-1 ), then XORs them together to create the MAC.
* SSL 3. 0 improved upon SSL 2. 0 by adding SHA-1 based ciphers and support for certificate authentication.
Under TLS 1. 0, the master key that is established depends on both MD5 and SHA-1 so its derivation process is not currently considered weak.
Version 5 UUIDs use a scheme with SHA-1 hashing ; otherwise it is the same idea as in version 3.
Note that the 160 bit SHA-1 hash is truncated to 128 bits to make the length work out.
SHA-1 and cryptography
The ASF container can optionally support digital rights management using a combination of elliptic curve cryptography key exchange, DES block cipher, a custom block cipher, RC4 stream cipher and the SHA-1 hashing function.
An analysis of an older scheme used in WMA reveals that it is using a combination of elliptic curve cryptography key exchange, DES block cipher, a custom block cipher, RC4 stream cipher and the SHA-1 hashing function.
SHA-1 and message
To store a file with given and in the DHT, the SHA-1 hash of is generated, producing a 160-bit key, and a message is sent to any node participating in the DHT.
| 160 bits – maximum key length of the SHA-1, standard Tiger ( hash ), and Tiger2 cryptographic message digest algorithms
SHA-1 and is
In addition, each resource is identified by a unique ID, a 160 bit SHA-1 URN in the Java binding, so that a peer can change its localization address while keeping a constant identification number.
The SHA-1 algorithm is the base hashing function for consistent hashing.
All well-known hash functions, including MD4, MD5, SHA-1 and SHA-2 are built from block-cipher-like components designed for the purpose, with feedback to ensure that the resulting function is not bijective.
SEAL is a stream cipher that uses SHA-1 to generate internal tables, which are then used in a keystream generator more or less unrelated to the hash algorithm.
SEAL is not guaranteed to be as strong ( or weak ) as SHA-1.
Among the n messages with the same MD5 hash, there is likely to be a collision in SHA-1.
The additional work needed to find the SHA-1 collision ( beyond the exponential birthday search ) is polynomial.
# Alice immediately computes a SHA-1 hash of the string " tail ljngjkrjgnfdudiudd gfdgdfjkherfsfsd ", which is 59dea408d43183a3937957e71a4bcacc616d9cbc and sends it to Bob
Despite the weaknesses of the SFV format, it is popular due to the relatively small amount of time taken by SFV utilities to calculate the CRC32 checksums when compared to the time taken to calculate cryptographic hashes such as MD5 or SHA-1.
SHACAL-1 ( originally simply SHACAL ) is a 160-bit block cipher based on SHA-1, and supports keys from 128-bit to 512-bit.
SHACAL-1 is based on the following observation of SHA-1:
The hash function SHA-1 is designed around a compression function.
SHA-1 and specific
< dd > A non-standard URN representing a specific MP3 file of the I have a dream speech by Martin Luther King by its SHA-1 hash Base32 encoded .</ dd >
Monotone uses SHA-1 hashes to identify specific files or groups of files, as with Git and Mercurial, in place of linear revision numbers.
SHA-1 and construction
Also, many hash functions ( including SHA-1 and SHA-2 ) are built by using a special-purpose block cipher in a Davies-Meyer or other construction.
SHA-1 and for
But academic cryptanalysts tend to provide at least the estimated order of magnitude of their attacks ' difficulty, saying, for example, " SHA-1 collisions now 2 < sup > 52 </ sup >.
The peer creates a hash for each piece, using the SHA-1 hash function, and records it in the torrent file.
In February 2005, a successful attack on SHA-1 was reported, finding collisions in about 2 < sup > 69 </ sup > hashing operations, rather than the 2 < sup > 80 </ sup > expected for a 160-bit hash function.
: PRNG based on SHA-1 for general purposes in FIPS Pub 186-2 ( inc change notice 1 ) Appendix 3. 1
: PRNG based on SHA-1 for general purposes in FIPS Pub 186-2 ( inc change notice 1 ) revised Appendix 3. 1
* Hardware support for SHA-1 and SHA-256 hashing.
It features support for the BitTorrent protocol, Metalink, and podcast support, along with built-in verification MD5 and SHA-1 checksums.
Yarrow required each source of entropy to be accompanied by a mechanism for estimating the actual entropy supplied, and used only two pools ; and its suggested embodiment ( called Yarrow-160 ) used SHA-1 rather than iterated SHA-256.
Monotone is designed for distributed operation, and makes heavy use of cryptographic primitives to track file revisions ( via the SHA-1 secure hash ) and to authenticate user actions ( via RSA cryptographic signatures ).
It does this by comparing SHA-1 hashes of important files with known good ones in online database, searching for default directories ( of rootkits ), wrong permissions, hidden files, suspicious strings in kernel modules, and special tests for Linux and FreeBSD.
Usually a cryptographic hash function such as SHA-1 is used for the hashing.
Usually, a cryptographic hash function such as SHA-1, Whirlpool, or Tiger is used for the hashing.
0.219 seconds.