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Diffstat (limited to 'crypto/sha3/doc.go')
| -rw-r--r-- | crypto/sha3/doc.go | 66 |
1 files changed, 0 insertions, 66 deletions
diff --git a/crypto/sha3/doc.go b/crypto/sha3/doc.go deleted file mode 100644 index 3dab530f8..000000000 --- a/crypto/sha3/doc.go +++ /dev/null @@ -1,66 +0,0 @@ -// Copyright 2014 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// Package sha3 implements the SHA-3 fixed-output-length hash functions and -// the SHAKE variable-output-length hash functions defined by FIPS-202. -// -// Both types of hash function use the "sponge" construction and the Keccak -// permutation. For a detailed specification see http://keccak.noekeon.org/ -// -// -// Guidance -// -// If you aren't sure what function you need, use SHAKE256 with at least 64 -// bytes of output. The SHAKE instances are faster than the SHA3 instances; -// the latter have to allocate memory to conform to the hash.Hash interface. -// -// If you need a secret-key MAC (message authentication code), prepend the -// secret key to the input, hash with SHAKE256 and read at least 32 bytes of -// output. -// -// -// Security strengths -// -// The SHA3-x (x equals 224, 256, 384, or 512) functions have a security -// strength against preimage attacks of x bits. Since they only produce "x" -// bits of output, their collision-resistance is only "x/2" bits. -// -// The SHAKE-256 and -128 functions have a generic security strength of 256 and -// 128 bits against all attacks, provided that at least 2x bits of their output -// is used. Requesting more than 64 or 32 bytes of output, respectively, does -// not increase the collision-resistance of the SHAKE functions. -// -// -// The sponge construction -// -// A sponge builds a pseudo-random function from a public pseudo-random -// permutation, by applying the permutation to a state of "rate + capacity" -// bytes, but hiding "capacity" of the bytes. -// -// A sponge starts out with a zero state. To hash an input using a sponge, up -// to "rate" bytes of the input are XORed into the sponge's state. The sponge -// is then "full" and the permutation is applied to "empty" it. This process is -// repeated until all the input has been "absorbed". The input is then padded. -// The digest is "squeezed" from the sponge in the same way, except that output -// output is copied out instead of input being XORed in. -// -// A sponge is parameterized by its generic security strength, which is equal -// to half its capacity; capacity + rate is equal to the permutation's width. -// Since the KeccakF-1600 permutation is 1600 bits (200 bytes) wide, this means -// that the security strength of a sponge instance is equal to (1600 - bitrate) / 2. -// -// -// Recommendations -// -// The SHAKE functions are recommended for most new uses. They can produce -// output of arbitrary length. SHAKE256, with an output length of at least -// 64 bytes, provides 256-bit security against all attacks. The Keccak team -// recommends it for most applications upgrading from SHA2-512. (NIST chose a -// much stronger, but much slower, sponge instance for SHA3-512.) -// -// The SHA-3 functions are "drop-in" replacements for the SHA-2 functions. -// They produce output of the same length, with the same security strengths -// against all attacks. This means, in particular, that SHA3-256 only has -// 128-bit collision resistance, because its output length is 32 bytes. -package sha3 |