gtsocial-umbx

argon2.go (9415B)

---

 // Copyright 2017 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 argon2 implements the key derivation function Argon2.
 // Argon2 was selected as the winner of the Password Hashing Competition and can
 // be used to derive cryptographic keys from passwords.
 //
 // For a detailed specification of Argon2 see [1].
 //
 // If you aren't sure which function you need, use Argon2id (IDKey) and
 // the parameter recommendations for your scenario.
 //
 // # Argon2i
 //
 // Argon2i (implemented by Key) is the side-channel resistant version of Argon2.
 // It uses data-independent memory access, which is preferred for password
 // hashing and password-based key derivation. Argon2i requires more passes over
 // memory than Argon2id to protect from trade-off attacks. The recommended
 // parameters (taken from [2]) for non-interactive operations are time=3 and to
 // use the maximum available memory.
 //
 // # Argon2id
 //
 // Argon2id (implemented by IDKey) is a hybrid version of Argon2 combining
 // Argon2i and Argon2d. It uses data-independent memory access for the first
 // half of the first iteration over the memory and data-dependent memory access
 // for the rest. Argon2id is side-channel resistant and provides better brute-
 // force cost savings due to time-memory tradeoffs than Argon2i. The recommended
 // parameters for non-interactive operations (taken from [2]) are time=1 and to
 // use the maximum available memory.
 //
 // [1] https://github.com/P-H-C/phc-winner-argon2/blob/master/argon2-specs.pdf
 // [2] https://tools.ietf.org/html/draft-irtf-cfrg-argon2-03#section-9.3
 package argon2
 
 import (
 	"encoding/binary"
 	"sync"
 
 	"golang.org/x/crypto/blake2b"
 )
 
 // The Argon2 version implemented by this package.
 const Version = 0x13
 
 const (
 	argon2d = iota
 	argon2i
 	argon2id
 )
 
 // Key derives a key from the password, salt, and cost parameters using Argon2i
 // returning a byte slice of length keyLen that can be used as cryptographic
 // key. The CPU cost and parallelism degree must be greater than zero.
 //
 // For example, you can get a derived key for e.g. AES-256 (which needs a
 // 32-byte key) by doing:
 //
 //	key := argon2.Key([]byte("some password"), salt, 3, 32*1024, 4, 32)
 //
 // The draft RFC recommends[2] time=3, and memory=32*1024 is a sensible number.
 // If using that amount of memory (32 MB) is not possible in some contexts then
 // the time parameter can be increased to compensate.
 //
 // The time parameter specifies the number of passes over the memory and the
 // memory parameter specifies the size of the memory in KiB. For example
 // memory=32*1024 sets the memory cost to ~32 MB. The number of threads can be
 // adjusted to the number of available CPUs. The cost parameters should be
 // increased as memory latency and CPU parallelism increases. Remember to get a
 // good random salt.
 func Key(password, salt []byte, time, memory uint32, threads uint8, keyLen uint32) []byte {
 	return deriveKey(argon2i, password, salt, nil, nil, time, memory, threads, keyLen)
 }
 
 // IDKey derives a key from the password, salt, and cost parameters using
 // Argon2id returning a byte slice of length keyLen that can be used as
 // cryptographic key. The CPU cost and parallelism degree must be greater than
 // zero.
 //
 // For example, you can get a derived key for e.g. AES-256 (which needs a
 // 32-byte key) by doing:
 //
 //	key := argon2.IDKey([]byte("some password"), salt, 1, 64*1024, 4, 32)
 //
 // The draft RFC recommends[2] time=1, and memory=64*1024 is a sensible number.
 // If using that amount of memory (64 MB) is not possible in some contexts then
 // the time parameter can be increased to compensate.
 //
 // The time parameter specifies the number of passes over the memory and the
 // memory parameter specifies the size of the memory in KiB. For example
 // memory=64*1024 sets the memory cost to ~64 MB. The number of threads can be
 // adjusted to the numbers of available CPUs. The cost parameters should be
 // increased as memory latency and CPU parallelism increases. Remember to get a
 // good random salt.
 func IDKey(password, salt []byte, time, memory uint32, threads uint8, keyLen uint32) []byte {
 	return deriveKey(argon2id, password, salt, nil, nil, time, memory, threads, keyLen)
 }
 
 func deriveKey(mode int, password, salt, secret, data []byte, time, memory uint32, threads uint8, keyLen uint32) []byte {
 	if time < 1 {
 		panic("argon2: number of rounds too small")
 	}
 	if threads < 1 {
 		panic("argon2: parallelism degree too low")
 	}
 	h0 := initHash(password, salt, secret, data, time, memory, uint32(threads), keyLen, mode)
 
 	memory = memory / (syncPoints * uint32(threads)) * (syncPoints * uint32(threads))
 	if memory < 2*syncPoints*uint32(threads) {
 		memory = 2 * syncPoints * uint32(threads)
 	}
 	B := initBlocks(&h0, memory, uint32(threads))
 	processBlocks(B, time, memory, uint32(threads), mode)
 	return extractKey(B, memory, uint32(threads), keyLen)
 }
 
 const (
 	blockLength = 128
 	syncPoints  = 4
 )
 
 type block [blockLength]uint64
 
 func initHash(password, salt, key, data []byte, time, memory, threads, keyLen uint32, mode int) [blake2b.Size + 8]byte {
 	var (
 		h0     [blake2b.Size + 8]byte
 		params [24]byte
 		tmp    [4]byte
 	)
 
 	b2, _ := blake2b.New512(nil)
 	binary.LittleEndian.PutUint32(params[0:4], threads)
 	binary.LittleEndian.PutUint32(params[4:8], keyLen)
 	binary.LittleEndian.PutUint32(params[8:12], memory)
 	binary.LittleEndian.PutUint32(params[12:16], time)
 	binary.LittleEndian.PutUint32(params[16:20], uint32(Version))
 	binary.LittleEndian.PutUint32(params[20:24], uint32(mode))
 	b2.Write(params[:])
 	binary.LittleEndian.PutUint32(tmp[:], uint32(len(password)))
 	b2.Write(tmp[:])
 	b2.Write(password)
 	binary.LittleEndian.PutUint32(tmp[:], uint32(len(salt)))
 	b2.Write(tmp[:])
 	b2.Write(salt)
 	binary.LittleEndian.PutUint32(tmp[:], uint32(len(key)))
 	b2.Write(tmp[:])
 	b2.Write(key)
 	binary.LittleEndian.PutUint32(tmp[:], uint32(len(data)))
 	b2.Write(tmp[:])
 	b2.Write(data)
 	b2.Sum(h0[:0])
 	return h0
 }
 
 func initBlocks(h0 *[blake2b.Size + 8]byte, memory, threads uint32) []block {
 	var block0 [1024]byte
 	B := make([]block, memory)
 	for lane := uint32(0); lane < threads; lane++ {
 		j := lane * (memory / threads)
 		binary.LittleEndian.PutUint32(h0[blake2b.Size+4:], lane)
 
 		binary.LittleEndian.PutUint32(h0[blake2b.Size:], 0)
 		blake2bHash(block0[:], h0[:])
 		for i := range B[j+0] {
 			B[j+0][i] = binary.LittleEndian.Uint64(block0[i*8:])
 		}
 
 		binary.LittleEndian.PutUint32(h0[blake2b.Size:], 1)
 		blake2bHash(block0[:], h0[:])
 		for i := range B[j+1] {
 			B[j+1][i] = binary.LittleEndian.Uint64(block0[i*8:])
 		}
 	}
 	return B
 }
 
 func processBlocks(B []block, time, memory, threads uint32, mode int) {
 	lanes := memory / threads
 	segments := lanes / syncPoints
 
 	processSegment := func(n, slice, lane uint32, wg *sync.WaitGroup) {
 		var addresses, in, zero block
 		if mode == argon2i || (mode == argon2id && n == 0 && slice < syncPoints/2) {
 			in[0] = uint64(n)
 			in[1] = uint64(lane)
 			in[2] = uint64(slice)
 			in[3] = uint64(memory)
 			in[4] = uint64(time)
 			in[5] = uint64(mode)
 		}
 
 		index := uint32(0)
 		if n == 0 && slice == 0 {
 			index = 2 // we have already generated the first two blocks
 			if mode == argon2i || mode == argon2id {
 				in[6]++
 				processBlock(&addresses, &in, &zero)
 				processBlock(&addresses, &addresses, &zero)
 			}
 		}
 
 		offset := lane*lanes + slice*segments + index
 		var random uint64
 		for index < segments {
 			prev := offset - 1
 			if index == 0 && slice == 0 {
 				prev += lanes // last block in lane
 			}
 			if mode == argon2i || (mode == argon2id && n == 0 && slice < syncPoints/2) {
 				if index%blockLength == 0 {
 					in[6]++
 					processBlock(&addresses, &in, &zero)
 					processBlock(&addresses, &addresses, &zero)
 				}
 				random = addresses[index%blockLength]
 			} else {
 				random = B[prev][0]
 			}
 			newOffset := indexAlpha(random, lanes, segments, threads, n, slice, lane, index)
 			processBlockXOR(&B[offset], &B[prev], &B[newOffset])
 			index, offset = index+1, offset+1
 		}
 		wg.Done()
 	}
 
 	for n := uint32(0); n < time; n++ {
 		for slice := uint32(0); slice < syncPoints; slice++ {
 			var wg sync.WaitGroup
 			for lane := uint32(0); lane < threads; lane++ {
 				wg.Add(1)
 				go processSegment(n, slice, lane, &wg)
 			}
 			wg.Wait()
 		}
 	}
 
 }
 
 func extractKey(B []block, memory, threads, keyLen uint32) []byte {
 	lanes := memory / threads
 	for lane := uint32(0); lane < threads-1; lane++ {
 		for i, v := range B[(lane*lanes)+lanes-1] {
 			B[memory-1][i] ^= v
 		}
 	}
 
 	var block [1024]byte
 	for i, v := range B[memory-1] {
 		binary.LittleEndian.PutUint64(block[i*8:], v)
 	}
 	key := make([]byte, keyLen)
 	blake2bHash(key, block[:])
 	return key
 }
 
 func indexAlpha(rand uint64, lanes, segments, threads, n, slice, lane, index uint32) uint32 {
 	refLane := uint32(rand>>32) % threads
 	if n == 0 && slice == 0 {
 		refLane = lane
 	}
 	m, s := 3*segments, ((slice+1)%syncPoints)*segments
 	if lane == refLane {
 		m += index
 	}
 	if n == 0 {
 		m, s = slice*segments, 0
 		if slice == 0 || lane == refLane {
 			m += index
 		}
 	}
 	if index == 0 || lane == refLane {
 		m--
 	}
 	return phi(rand, uint64(m), uint64(s), refLane, lanes)
 }
 
 func phi(rand, m, s uint64, lane, lanes uint32) uint32 {
 	p := rand & 0xFFFFFFFF
 	p = (p * p) >> 32
 	p = (p * m) >> 32
 	return lane*lanes + uint32((s+m-(p+1))%uint64(lanes))
 }