289b30715d
This commit converts the dependency management from Godeps to the vendor folder, also switching the tool from godep to trash. Since the upstream tool lacks a few features proposed via a few PRs, until those PRs are merged in (if), use github.com/karalabe/trash. You can update dependencies via trash --update. All dependencies have been updated to their latest version. Parts of the build system are reworked to drop old notions of Godeps and invocation of the go vet command so that it doesn't run against the vendor folder, as that will just blow up during vetting. The conversion drops OpenCL (and hence GPU mining support) from ethash and our codebase. The short reasoning is that there's noone to maintain and having opencl libs in our deps messes up builds as go install ./... tries to build them, failing with unsatisfied link errors for the C OpenCL deps. golang.org/x/net/context is not vendored in. We expect it to be fetched by the user (i.e. using go get). To keep ci.go builds reproducible the package is "vendored" in build/_vendor.
78 lines
2.4 KiB
Go
78 lines
2.4 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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/*
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Package pbkdf2 implements the key derivation function PBKDF2 as defined in RFC
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2898 / PKCS #5 v2.0.
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A key derivation function is useful when encrypting data based on a password
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or any other not-fully-random data. It uses a pseudorandom function to derive
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a secure encryption key based on the password.
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While v2.0 of the standard defines only one pseudorandom function to use,
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HMAC-SHA1, the drafted v2.1 specification allows use of all five FIPS Approved
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Hash Functions SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512 for HMAC. To
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choose, you can pass the `New` functions from the different SHA packages to
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pbkdf2.Key.
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*/
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package pbkdf2 // import "golang.org/x/crypto/pbkdf2"
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import (
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"crypto/hmac"
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"hash"
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)
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// Key derives a key from the password, salt and iteration count, returning a
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// []byte of length keylen that can be used as cryptographic key. The key is
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// derived based on the method described as PBKDF2 with the HMAC variant using
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// the supplied hash function.
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//
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// For example, to use a HMAC-SHA-1 based PBKDF2 key derivation function, you
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// can get a derived key for e.g. AES-256 (which needs a 32-byte key) by
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// doing:
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//
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// dk := pbkdf2.Key([]byte("some password"), salt, 4096, 32, sha1.New)
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//
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// Remember to get a good random salt. At least 8 bytes is recommended by the
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// RFC.
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//
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// Using a higher iteration count will increase the cost of an exhaustive
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// search but will also make derivation proportionally slower.
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func Key(password, salt []byte, iter, keyLen int, h func() hash.Hash) []byte {
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prf := hmac.New(h, password)
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hashLen := prf.Size()
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numBlocks := (keyLen + hashLen - 1) / hashLen
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var buf [4]byte
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dk := make([]byte, 0, numBlocks*hashLen)
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U := make([]byte, hashLen)
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for block := 1; block <= numBlocks; block++ {
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// N.B.: || means concatenation, ^ means XOR
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// for each block T_i = U_1 ^ U_2 ^ ... ^ U_iter
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// U_1 = PRF(password, salt || uint(i))
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prf.Reset()
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prf.Write(salt)
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buf[0] = byte(block >> 24)
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buf[1] = byte(block >> 16)
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buf[2] = byte(block >> 8)
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buf[3] = byte(block)
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prf.Write(buf[:4])
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dk = prf.Sum(dk)
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T := dk[len(dk)-hashLen:]
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copy(U, T)
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// U_n = PRF(password, U_(n-1))
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for n := 2; n <= iter; n++ {
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prf.Reset()
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prf.Write(U)
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U = U[:0]
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U = prf.Sum(U)
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for x := range U {
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T[x] ^= U[x]
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}
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}
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}
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return dk[:keyLen]
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}
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