Remove Go code in favor of upstream libscrypt-kdf

Adapt build to handle cgo shenanigans.

9 files changed, 197 insertions, 508 deletions

diff --git a/.gitignore b/.gitignore
index d910245..6063315 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 /src/version.go
 /*.bin
+/src/*cgo*
 /src/*.a
 /src/*.bin
 /tests/*.a
diff --git a/Makefile b/Makefile
index b25ed41..ca227e9 100644
--- a/Makefile
+++ b/Makefile
@@ -17,22 +17,23 @@ MANDIR       = $(SHAREDIR)/man
 EXEC         = ./
 ## Where to store the installation.  Empty by default.
 DESTDIR      =
-LDLIBS       =
+LDLIBS       = --static -lscrypt-kdf
 GOCFLAGS     = -I $(GOLIBDIR)
 GOLDFLAGS    = -L $(GOLIBDIR)
 
 
 
 .SUFFIXES:
-.SUFFIXES: .go .a .bin .bin-check
+.SUFFIXES: .go .a .c .o .bin .bin-check
+
+.c.o:
+	$(CC) $(CFLAGS) -o $@ -c $<
 
 .go.a:
-	go tool compile $(GOCFLAGS) -I $(@D) -o $@ -p $(*F) \
-		`find $< $$(if [ $(*F) != main ]; then \
-			echo src/$(NAME).go src/version.go; fi) | uniq`
+	go tool compile $(GOCFLAGS)  -I $(@D) -o $@ -p $(*F) $<
 
 .a.bin:
-	go tool link $(GOLDFLAGS)   -L $(@D) -o $@ --extldflags '$(LDLIBS)' $<
+	go tool link    $(GOLDFLAGS) -L $(@D) -o $@ --extldflags '$(LDLIBS)' $<
 
 
 
@@ -47,6 +48,23 @@ functional-tests/lib.a = $(functional-tests/lib.go:.go=.a)
 fuzz-targets/lib.a     = $(fuzz-targets/lib.go:.go=.a)
 benchmarks/lib.a       = $(benchmarks/lib.go:.go=.a)
 
+cgo.go = \
+	src/_cgo_import.go             \
+	src/_cgo_gotypes.go            \
+	src/$(NAME).cgo1.go            \
+
+cgo.c = \
+	src/_cgo_export.c              \
+	src/$(NAME).cgo2.c             \
+
+cgo.o = $(cgo.c:.c=.o)
+
+objects = \
+	src/_cgo_.o                    \
+	$(cgo.go)                      \
+	$(cgo.c)                       \
+	$(cgo.o)                       \
+
 sources = \
 	src/$(NAME).go                 \
 	src/version.go                 \
@@ -55,12 +73,15 @@ sources = \
 
 derived-assets = \
 	src/version.go                 \
+	$(objects)                     \
 	$(libs.a)                      \
 	$(mains.a)                     \
 	$(mains.bin)                   \
 	$(NAME).bin                    \
 
 side-assets = \
+	src/_cgo_export.h              \
+	src/_cgo_main.c                \
 	tests/fuzz/corpus/             \
 	tests/benchmarks/*/main.txt    \
 
@@ -71,13 +92,29 @@ side-assets = \
 all: $(derived-assets)
 
 
+$(objects): Makefile deps.mk
 $(libs.a): Makefile deps.mk
 $(libs.a): src/$(NAME).go src/version.go
+$(libs.a): $(cgo.go) $(cgo.o)
+
+$(cgo.go) $(cgo.c) $(cgo.o): src/_cgo_.o
+
+
+src/_cgo_.o: src/$(NAME).go
+	go tool cgo --objdir $(@D) src/$(NAME).go
+
+src/_cgo_import.go: src/_cgo_.o
+	go tool cgo --dynpackage $(NAME) --dynimport src/_cgo_.o --dynout $@
 
+src/$(NAME).a tests/$(NAME).a $(functional-tests/lib.a) $(benchmarks/lib.a):
+	go tool compile $(GOCFLAGS) -o $@ -p $(*F) $(cgo.go) src/version.go \
+		`find $*.go | grep -Ev '^src/$(NAME)\.go$$'`
+	go tool pack r $@ $(cgo.o)
 
 $(fuzz-targets/lib.a):
 	go tool compile $(GOCFLAGS) -o $@ -p $(NAME) -d=libfuzzer \
-		src/version.go $*.go src/$(NAME).go
+		$*.go $(cgo.go) src/version.go
+	go tool pack r $@ $(cgo.o)
 
 src/version.go: Makefile
 	echo 'package $(NAME); const Version = "$(VERSION)"' > $@
diff --git a/deps.mk b/deps.mk
index 1c60984..783970b 100644
--- a/deps.mk
+++ b/deps.mk
@@ -2,6 +2,7 @@ libs.go = \
 	src/scrypt.go \
 	tests/benchmarks/hash/scrypt.go \
 	tests/functional/hash-and-check/scrypt.go \
+	tests/functional/version/scrypt.go \
 	tests/fuzz/api/scrypt.go \
 	tests/scrypt.go \
 
@@ -9,14 +10,17 @@ mains.go = \
 	src/main.go \
 	tests/benchmarks/hash/main.go \
 	tests/functional/hash-and-check/main.go \
+	tests/functional/version/main.go \
 	tests/fuzz/api/main.go \
 	tests/main.go \
 
-functional-tests/libs.go = \
+functional-tests/lib.go = \
 	tests/functional/hash-and-check/scrypt.go \
+	tests/functional/version/scrypt.go \
 
 functional-tests/main.go = \
 	tests/functional/hash-and-check/main.go \
+	tests/functional/version/main.go \
 
 fuzz-targets/lib.go = \
 	tests/fuzz/api/scrypt.go \
@@ -36,6 +40,8 @@ tests/benchmarks/hash/main.a:	tests/benchmarks/hash/main.go
 tests/benchmarks/hash/scrypt.a:	tests/benchmarks/hash/scrypt.go
 tests/functional/hash-and-check/main.a:	tests/functional/hash-and-check/main.go
 tests/functional/hash-and-check/scrypt.a:	tests/functional/hash-and-check/scrypt.go
+tests/functional/version/main.a:	tests/functional/version/main.go
+tests/functional/version/scrypt.a:	tests/functional/version/scrypt.go
 tests/fuzz/api/main.a:	tests/fuzz/api/main.go
 tests/fuzz/api/scrypt.a:	tests/fuzz/api/scrypt.go
 tests/main.a:	tests/main.go
@@ -43,15 +49,18 @@ tests/scrypt.a:	tests/scrypt.go
 src/main.bin:	src/main.a
 tests/benchmarks/hash/main.bin:	tests/benchmarks/hash/main.a
 tests/functional/hash-and-check/main.bin:	tests/functional/hash-and-check/main.a
+tests/functional/version/main.bin:	tests/functional/version/main.a
 tests/fuzz/api/main.bin:	tests/fuzz/api/main.a
 tests/main.bin:	tests/main.a
 src/main.bin-check:	src/main.bin
 tests/benchmarks/hash/main.bin-check:	tests/benchmarks/hash/main.bin
 tests/functional/hash-and-check/main.bin-check:	tests/functional/hash-and-check/main.bin
+tests/functional/version/main.bin-check:	tests/functional/version/main.bin
 tests/fuzz/api/main.bin-check:	tests/fuzz/api/main.bin
 tests/main.bin-check:	tests/main.bin
 src/main.a:	src/$(NAME).a
 tests/benchmarks/hash/main.a:	tests/benchmarks/hash/$(NAME).a
 tests/functional/hash-and-check/main.a:	tests/functional/hash-and-check/$(NAME).a
+tests/functional/version/main.a:	tests/functional/version/$(NAME).a
 tests/fuzz/api/main.a:	tests/fuzz/api/$(NAME).a
 tests/main.a:	tests/$(NAME).a
diff --git a/mkdeps.sh b/mkdeps.sh
index b1c61b3..e8da8a4 100755
--- a/mkdeps.sh
+++ b/mkdeps.sh
@@ -16,7 +16,7 @@ mains() {
 libs  | varlist 'libs.go'
 mains | varlist 'mains.go'
 
-find tests/functional/*/*.go -not -name main.go | varlist 'functional-tests/libs.go'
+find tests/functional/*/*.go -not -name main.go | varlist 'functional-tests/lib.go'
 find tests/functional/*/main.go                 | varlist 'functional-tests/main.go'
 find tests/fuzz/*/*.go       -not -name main.go | varlist 'fuzz-targets/lib.go'
 find tests/fuzz/*/main.go                       | varlist 'fuzz-targets/main.go'
diff --git a/src/scrypt.go b/src/scrypt.go
index fe6cb8d..a4f03d2 100644
--- a/src/scrypt.go
+++ b/src/scrypt.go
@@ -1,28 +1,30 @@
 package scrypt
 
 import (
-	"crypto/hmac"
 	"crypto/rand"
-	"crypto/sha256"
-	"encoding/binary"
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"hash"
 	"io"
-	"math/bits"
 	"os"
 	"slices"
 )
 
 
 
+/*
+#define _XOPEN_SOURCE 700
+#include <stdlib.h>
+#include <scrypt-kdf.h>
+*/
+import "C"
+
+
+
 const (
-	saltMinLength = 32
-	desiredLength = 32
-	maxInt                = int((^uint(0)) >> 1)
 	MinimumPasswordLength = 16
-
+	_SALT_MIN_LENGTH = 32
+	_DESIRED_LENGTH = 32
 	_N = 1 << 15
 	r  = 8
 	p  = 1
@@ -30,274 +32,12 @@ const (
 
 
 var (
-	ErrBadN           = errors.New("scrypt: N must be > 1 and a power of 2")
-	ErrParamsTooLarge = errors.New("scrypt: parameters are too large")
-	ErrSaltTooSmall   = errors.New("scrypt: salt is too small")
+	ErrSaltTooSmall = errors.New("scrypt: salt is too small")
+	ErrInternal     = errors.New("scrypt: internal error")
 )
 
 
 
-// Package pbkdf2 implements the key derivation function PBKDF2 as defined in
-// RFC 2898 / PKCS #5 v2.0.
-//
-// A key derivation function is useful when encrypting data based on a password
-// or any other not-fully-random data. It uses a pseudorandom function to derive
-// a secure encryption key based on the password.
-//
-// While v2.0 of the standard defines only one pseudorandom function to use,
-// HMAC-SHA1, the drafted v2.1 specification allows use of all five FIPS
-// Approved Hash Functions SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512 for
-// HMAC. To choose, you can pass the `New` functions from the different SHA
-// packages to pbkdf2.Key.
-//
-//
-// Key derives a key from the password, salt and iteration count, returning a
-// []byte of length keylen that can be used as cryptographic key. The key is
-// derived based on the method described as PBKDF2 with the HMAC variant using
-// the supplied hash function.
-//
-// For example, to use a HMAC-SHA-1 based PBKDF2 key derivation function, you
-// can get a derived key for e.g. AES-256 (which needs a 32-byte key) by
-// doing:
-//
-//	dk := pbkdf2.Key([]byte("some password"), salt, 4096, 32, sha1.New)
-//
-// Remember to get a good random salt. At least 8 bytes is recommended by the
-// RFC.
-//
-// Using a higher iteration count will increase the cost of an exhaustive
-// search but will also make derivation proportionally slower.
-func _PBKDF2Key(
-	password []byte,
-	salt []byte,
-	iter int,
-	keyLen int,
-	h func() hash.Hash,
-) []byte {
-	prf := hmac.New(h, password)
-	hashLen := prf.Size()
-	numBlocks := (keyLen + hashLen - 1) / hashLen
-
-	var buffer [4]byte
-	dk := make([]byte, 0, numBlocks*hashLen)
-	U := make([]byte, hashLen)
-	for block := 1; block <= numBlocks; block++ {
-		// N.B.: || means concatenation, ^ means XOR
-		// for each block T_i = U_1 ^ U_2 ^ ... ^ U_iter
-		// U_1 = PRF(password, salt || uint(i))
-		prf.Reset()
-		prf.Write(salt)
-		buffer[0] = byte(block >> 24)
-		buffer[1] = byte(block >> 16)
-		buffer[2] = byte(block >> 8)
-		buffer[3] = byte(block >> 0)
-		prf.Write(buffer[:4])
-		dk = prf.Sum(dk)
-		T := dk[len(dk) - hashLen:]
-		copy(U, T)
-
-		// U_n = PRF(password, U_(n - 1))
-		for n := 2; n <= iter; n++ {
-			prf.Reset()
-			prf.Write(U)
-			U = U[:0]
-			U = prf.Sum(U)
-			for x := range U {
-				T[x] ^= U[x]
-			}
-		}
-	}
-	return dk[:keyLen]
-}
-
-// blockCopy copies n numbers from src into dst.
-func blockCopy(dst []uint32, src []uint32, n int) {
-	copy(dst, src[:n])
-}
-
-// blockXOR XORs numbers from dst with n numbers from src.
-func blockXOR(dst []uint32, src []uint32, n int) {
-	for i, v := range src[:n] {
-		dst[i] ^= v
-	}
-}
-
-// salsaXOR applies Salsa20/8 to the XOR of 16 numbers from tmp and in,
-// and puts the result into both tmp and out.
-func salsaXOR(tmp *[16]uint32, in []uint32, out []uint32) {
-	w0  := tmp[0]  ^ in[0]
-	w1  := tmp[1]  ^ in[1]
-	w2  := tmp[2]  ^ in[2]
-	w3  := tmp[3]  ^ in[3]
-	w4  := tmp[4]  ^ in[4]
-	w5  := tmp[5]  ^ in[5]
-	w6  := tmp[6]  ^ in[6]
-	w7  := tmp[7]  ^ in[7]
-	w8  := tmp[8]  ^ in[8]
-	w9  := tmp[9]  ^ in[9]
-	w10 := tmp[10] ^ in[10]
-	w11 := tmp[11] ^ in[11]
-	w12 := tmp[12] ^ in[12]
-	w13 := tmp[13] ^ in[13]
-	w14 := tmp[14] ^ in[14]
-	w15 := tmp[15] ^ in[15]
-
-	x0  := w0
-	x1  := w1
-	x2  := w2
-	x3  := w3
-	x4  := w4
-	x5  := w5
-	x6  := w6
-	x7  := w7
-	x8  := w8
-	x9  := w9
-	x10 := w10
-	x11 := w11
-	x12 := w12
-	x13 := w13
-	x14 := w14
-	x15 := w15
-
-	for i := 0; i < 8; i += 2 {
-		x4  ^= bits.RotateLeft32(x0  + x12, 7)
-		x8  ^= bits.RotateLeft32(x4  + x0,  9)
-		x12 ^= bits.RotateLeft32(x8  + x4,  13)
-		x0  ^= bits.RotateLeft32(x12 + x8,  18)
-
-		x9  ^= bits.RotateLeft32(x5  + x1,  7)
-		x13 ^= bits.RotateLeft32(x9  + x5,  9)
-		x1  ^= bits.RotateLeft32(x13 + x9,  13)
-		x5  ^= bits.RotateLeft32(x1  + x13, 18)
-
-		x14 ^= bits.RotateLeft32(x10 + x6,  7)
-		x2  ^= bits.RotateLeft32(x14 + x10, 9)
-		x6  ^= bits.RotateLeft32(x2  + x14, 13)
-		x10 ^= bits.RotateLeft32(x6  + x2,  18)
-
-		x3  ^= bits.RotateLeft32(x15 + x11, 7)
-		x7  ^= bits.RotateLeft32(x3  + x15, 9)
-		x11 ^= bits.RotateLeft32(x7  + x3,  13)
-		x15 ^= bits.RotateLeft32(x11 + x7,  18)
-
-		x1  ^= bits.RotateLeft32(x0  + x3,  7)
-		x2  ^= bits.RotateLeft32(x1  + x0,  9)
-		x3  ^= bits.RotateLeft32(x2  + x1,  13)
-		x0  ^= bits.RotateLeft32(x3  + x2,  18)
-
-		x6  ^= bits.RotateLeft32(x5  + x4,  7)
-		x7  ^= bits.RotateLeft32(x6  + x5,  9)
-		x4  ^= bits.RotateLeft32(x7  + x6,  13)
-		x5  ^= bits.RotateLeft32(x4  + x7,  18)
-
-		x11 ^= bits.RotateLeft32(x10 + x9,  7)
-		x8  ^= bits.RotateLeft32(x11 + x10, 9)
-		x9  ^= bits.RotateLeft32(x8  + x11, 13)
-		x10 ^= bits.RotateLeft32(x9  + x8,  18)
-
-		x12 ^= bits.RotateLeft32(x15 + x14, 7)
-		x13 ^= bits.RotateLeft32(x12 + x15, 9)
-		x14 ^= bits.RotateLeft32(x13 + x12, 13)
-		x15 ^= bits.RotateLeft32(x14 + x13, 18)
-	}
-
-	x0  += w0
-	x1  += w1
-	x2  += w2
-	x3  += w3
-	x4  += w4
-	x5  += w5
-	x6  += w6
-	x7  += w7
-	x8  += w8
-	x9  += w9
-	x10 += w10
-	x11 += w11
-	x12 += w12
-	x13 += w13
-	x14 += w14
-	x15 += w15
-
-	out[0],  tmp[0]  = x0,  x0
-	out[1],  tmp[1]  = x1,  x1
-	out[2],  tmp[2]  = x2,  x2
-	out[3],  tmp[3]  = x3,  x3
-	out[4],  tmp[4]  = x4,  x4
-	out[5],  tmp[5]  = x5,  x5
-	out[6],  tmp[6]  = x6,  x6
-	out[7],  tmp[7]  = x7,  x7
-	out[8],  tmp[8]  = x8,  x8
-	out[9],  tmp[9]  = x9,  x9
-	out[10], tmp[10] = x10, x10
-	out[11], tmp[11] = x11, x11
-	out[12], tmp[12] = x12, x12
-	out[13], tmp[13] = x13, x13
-	out[14], tmp[14] = x14, x14
-	out[15], tmp[15] = x15, x15
-}
-
-func blockMix(tmp *[16]uint32, in []uint32, out []uint32, r int) {
-	blockCopy(tmp[:], in[(2 * r - 1) * 16:], 16)
-	for i := 0; i < 2 * r; i += 2 {
-		salsaXOR(tmp, in[i * 16:],      out[i * 8:])
-		salsaXOR(tmp, in[i * 16 + 16:], out[i * 8 + r * 16:])
-	}
-}
-
-func integer(b []uint32, r int) uint64 {
-	j := (2 * r - 1) * 16
-	return uint64(b[j]) | (uint64(b[j + 1]) << 32)
-}
-
-func smix(b []byte, r int, N int, v []uint32, xy []uint32) {
-	var tmp [16]uint32
-	R := 32 * r
-	x := xy
-	y := xy[R:]
-
-	j := 0
-	for i := 0; i < R; i++ {
-		x[i] = binary.LittleEndian.Uint32(b[j:])
-		j += 4
-	}
-	for i := 0; i < N; i += 2 {
-		blockCopy(v[i * R:], x, R)
-		blockMix(&tmp, x, y, r)
-
-		blockCopy(v[(i + 1) * R:], y, R)
-		blockMix(&tmp, y, x, r)
-	}
-	for i := 0; i < N; i += 2 {
-		j := int(integer(x, r) & uint64(N - 1))
-		blockXOR(x, v[j * R:], R)
-		blockMix(&tmp, x, y, r)
-
-		j = int(integer(y, r) & uint64(N - 1))
-		blockXOR(y, v[j * R:], R)
-		blockMix(&tmp, y, x, r)
-	}
-	j = 0
-	for _, v := range x[:R] {
-		binary.LittleEndian.PutUint32(b[j:], v)
-		j += 4
-	}
-}
-
-func validateParams(N int, r int, p int) error {
-	if N <= 1 || N & (N - 1) != 0 {
-		return ErrBadN
-	}
-
-	if ((uint64(r) * uint64(p)) >= (1 << 30)) ||
-			r > maxInt / 128 / p ||
-			r > maxInt / 256 ||
-			N > maxInt / 128 / r {
-		return ErrParamsTooLarge
-	}
-
-	return nil
-}
-
 // Package scrypt implements the scrypt key derivation function as defined in
 // Colin Percival's paper "Stronger Key Derivation via Sequential Memory-Hard
 // Functions" (https://www.tarsnap.com/scrypt/scrypt.pdf).
@@ -325,39 +65,37 @@ func scrypt(
 	N int,
 	r int,
 	p int,
-	keyLen int,
+	outlen int,
 ) ([]byte, error) {
-	err := validateParams(N, r, p)
-	if err != nil {
-		return nil, err
-	}
-
-	xy := make([]uint32, 64 * r)
-	v  := make([]uint32, 32 * r * N)
-	b  := _PBKDF2Key(password, salt, 1, p * 128 * r, sha256.New)
-
-	for i := 0; i < p; i++ {
-		smix(b[i * 128 * r:], r, N, v, xy)
-	}
-
-	return _PBKDF2Key(password, b, 1, keyLen, sha256.New), nil
-}
-
-func SaltFrom(r io.Reader) ([]byte, error) {
-	buffer := make([]byte, saltMinLength)
-	_, err := io.ReadFull(r, buffer)
-	if err != nil {
-		return nil, err
+	passwordbuf := C.CBytes(password)
+	saltbuf     := C.CBytes(salt)
+	defer C.free(passwordbuf)
+	defer C.free(saltbuf)
+
+	outbuf := C.malloc(C.size_t(outlen))
+	defer C.free(outbuf)
+
+	rv := C.scrypt_kdf(
+		(*C.uint8_t)(passwordbuf),
+		C.size_t(len(password)),
+		(*C.uint8_t)(saltbuf),
+		C.size_t(len(salt)),
+		C.uint64_t(N),
+		C.uint32_t(r),
+		C.uint32_t(p),
+		(*C.uint8_t)(outbuf),
+		C.size_t(outlen),
+	)
+	if rv != 0 {
+		return nil, ErrInternal
 	}
-	return buffer, nil
-}
 
-func Salt() ([]byte, error) {
-	return SaltFrom(rand.Reader)
+	out := C.GoBytes(outbuf, C.int(outlen))
+	return out, nil
 }
 
 func Hash(password []byte, salt []byte) ([]byte, error) {
-	if len(salt) < saltMinLength {
+	if len(salt) < _SALT_MIN_LENGTH {
 		return nil, ErrSaltTooSmall
 	}
 
@@ -367,7 +105,7 @@ func Hash(password []byte, salt []byte) ([]byte, error) {
 		_N,
 		r,
 		p,
-		desiredLength,
+		_DESIRED_LENGTH,
 	)
 	if err != nil {
 		return nil, err
@@ -376,6 +114,19 @@ func Hash(password []byte, salt []byte) ([]byte, error) {
 	return hash, nil
 }
 
+func SaltFrom(r io.Reader) ([]byte, error) {
+	buffer := make([]byte, _SALT_MIN_LENGTH)
+	_, err := io.ReadFull(r, buffer)
+	if err != nil {
+		return nil, err
+	}
+	return buffer, nil
+}
+
+func Salt() ([]byte, error) {
+	return SaltFrom(rand.Reader)
+}
+
 func Check(password []byte, salt []byte, hash []byte) (bool, error) {
 	candidate, err := Hash(password, salt)
 	if err != nil {
@@ -392,8 +143,10 @@ func Main() {
 		fmt.Fprintf(os.Stderr, "Usage: scrypt PASSWORD SALT\n")
 		os.Exit(2)
 	}
+	password := os.Args[1]
+	salt     := os.Args[2]
 
-	payload, err := Hash([]byte(os.Args[1]), []byte(os.Args[2]))
+	payload, err := Hash([]byte(password), []byte(salt))
 	if err != nil {
 		if err == ErrSaltTooSmall {
 			fmt.Fprintln(os.Stderr, err)
diff --git a/tests/functional/version/main.go b/tests/functional/version/main.go
new file mode 120000
index 0000000..f67563d
--- /dev/null
+++ b/tests/functional/version/main.go
@@ -0,0 +1 @@
+../../main.go
\ No newline at end of file
diff --git a/tests/functional/version/scrypt.go b/tests/functional/version/scrypt.go
new file mode 100644
index 0000000..5133f8c
--- /dev/null
+++ b/tests/functional/version/scrypt.go
@@ -0,0 +1,13 @@
+package scrypt
+
+import (
+	g "gobang"
+)
+
+
+
+func MainTest() {
+	g.Testing("we can get the lib version", func() {
+		g.TAssertEqual(len(Version) >= 5, true)
+	})
+}
diff --git a/tests/fuzz/api/scrypt.go b/tests/fuzz/api/scrypt.go
index eb29d2d..8e785a5 100644
--- a/tests/fuzz/api/scrypt.go
+++ b/tests/fuzz/api/scrypt.go
@@ -10,7 +10,7 @@ import (
 
 func api(f *testing.F) {
 	f.Fuzz(func(t *testing.T, password []byte, salt []byte) {
-		if len(salt) < saltMinLength {
+		if len(salt) < _SALT_MIN_LENGTH {
 			return
 		}
 
diff --git a/tests/scrypt.go b/tests/scrypt.go
index cb97b08..f499f84 100644
--- a/tests/scrypt.go
+++ b/tests/scrypt.go
@@ -1,175 +1,19 @@
 package scrypt
 
 import (
-	"crypto/sha1"
-	"crypto/sha256"
 	"encoding/base64"
-	// "encoding/hex"
-	"hash"
+	"strings"
 
 	g "gobang"
 )
 
 
 
-type pbkdfTestVector struct {
-	password string
-	salt     string
-	iter     int
-	output   []byte
-}
-
-// Test vectors from RFC 6070, http://tools.ietf.org/html/rfc6070
-var sha1TestVectors = []pbkdfTestVector {
-	{
-		"password",
-		"salt",
-		1,
-		[]byte {
-			0x0c, 0x60, 0xc8, 0x0f, 0x96, 0x1f, 0x0e, 0x71,
-			0xf3, 0xa9, 0xb5, 0x24, 0xaf, 0x60, 0x12, 0x06,
-			0x2f, 0xe0, 0x37, 0xa6,
-		},
-	},
-	{
-		"password",
-		"salt",
-		2,
-		[]byte{
-			0xea, 0x6c, 0x01, 0x4d, 0xc7, 0x2d, 0x6f, 0x8c,
-			0xcd, 0x1e, 0xd9, 0x2a, 0xce, 0x1d, 0x41, 0xf0,
-			0xd8, 0xde, 0x89, 0x57,
-		},
-	},
-	{
-		"password",
-		"salt",
-		4096,
-		[]byte{
-			0x4b, 0x00, 0x79, 0x01, 0xb7, 0x65, 0x48, 0x9a,
-			0xbe, 0xad, 0x49, 0xd9, 0x26, 0xf7, 0x21, 0xd0,
-			0x65, 0xa4, 0x29, 0xc1,
-		},
-	},
-	// // This one takes too long
-	// {
-	// 	"password",
-	// 	"salt",
-	// 	16777216,
-	// 	[]byte {
-	// 		0xee, 0xfe, 0x3d, 0x61, 0xcd, 0x4d, 0xa4, 0xe4,
-	// 		0xe9, 0x94, 0x5b, 0x3d, 0x6b, 0xa2, 0x15, 0x8c,
-	// 		0x26, 0x34, 0xe9, 0x84,
-	// 	},
-	// },
-	{
-		"passwordPASSWORDpassword",
-		"saltSALTsaltSALTsaltSALTsaltSALTsalt",
-		4096,
-		[]byte{
-			0x3d, 0x2e, 0xec, 0x4f, 0xe4, 0x1c, 0x84, 0x9b,
-			0x80, 0xc8, 0xd8, 0x36, 0x62, 0xc0, 0xe4, 0x4a,
-			0x8b, 0x29, 0x1a, 0x96, 0x4c, 0xf2, 0xf0, 0x70,
-			0x38,
-		},
-	},
-	{
-		"pass\000word",
-		"sa\000lt",
-		4096,
-		[]byte{
-			0x56, 0xfa, 0x6a, 0xa7, 0x55, 0x48, 0x09, 0x9d,
-			0xcc, 0x37, 0xd7, 0xf0, 0x34, 0x25, 0xe0, 0xc3,
-		},
-	},
-}
-
-// Test vectors from
-// http://stackoverflow.com/questions/5130513/pbkdf2-hmac-sha2-test-vectors
-var sha256TestVectors = []pbkdfTestVector {
-	{
-		"password",
-		"salt",
-		1,
-		[]byte {
-			0x12, 0x0f, 0xb6, 0xcf, 0xfc, 0xf8, 0xb3, 0x2c,
-			0x43, 0xe7, 0x22, 0x52, 0x56, 0xc4, 0xf8, 0x37,
-			0xa8, 0x65, 0x48, 0xc9,
-		},
-	},
-	{
-		"password",
-		"salt",
-		2,
-		[]byte {
-			0xae, 0x4d, 0x0c, 0x95, 0xaf, 0x6b, 0x46, 0xd3,
-			0x2d, 0x0a, 0xdf, 0xf9, 0x28, 0xf0, 0x6d, 0xd0,
-			0x2a, 0x30, 0x3f, 0x8e,
-		},
-	},
-	{
-		"password",
-		"salt",
-		4096,
-		[]byte {
-			0xc5, 0xe4, 0x78, 0xd5, 0x92, 0x88, 0xc8, 0x41,
-			0xaa, 0x53, 0x0d, 0xb6, 0x84, 0x5c, 0x4c, 0x8d,
-			0x96, 0x28, 0x93, 0xa0,
-		},
-	},
-	{
-		"passwordPASSWORDpassword",
-		"saltSALTsaltSALTsaltSALTsaltSALTsalt",
-		4096,
-		[]byte {
-			0x34, 0x8c, 0x89, 0xdb, 0xcb, 0xd3, 0x2b, 0x2f,
-			0x32, 0xd8, 0x14, 0xb8, 0x11, 0x6e, 0x84, 0xcf,
-			0x2b, 0x17, 0x34, 0x7e, 0xbc, 0x18, 0x00, 0x18,
-			0x1c,
-		},
-	},
-	{
-		"pass\000word",
-		"sa\000lt",
-		4096,
-		[]byte {
-			0x89, 0xb6, 0x9d, 0x05, 0x16, 0xf8, 0x29, 0x89,
-			0x3c, 0x69, 0x62, 0x26, 0x65, 0x0a, 0x86, 0x87,
-		},
-	},
-}
-
-func testHash(h func() hash.Hash, hashName string, vectors []pbkdfTestVector) {
-	for _, v := range vectors {
-		out := _PBKDF2Key(
-			[]byte(v.password),
-			[]byte(v.salt),
-			v.iter,
-			len(v.output),
-			h,
-		)
-		g.TAssertEqual(out, v.output)
-	}
-}
-
-func test__PBKDF() {
-	g.TestStart("_PBKDF()")
-
-	g.Testing("HMAC with SHA1", func() {
-		testHash(sha1.New, "SHA1", sha1TestVectors)
-	})
-
-	g.Testing("HMAC with SHA256", func() {
-		testHash(sha256.New, "SHA256", sha256TestVectors)
-	})
-}
-
 type scryptTestVector struct {
 	password string
 	salt     string
 	N, r, p  int
 	output   []byte
-	err      error
 }
 
 var good = []scryptTestVector {
@@ -183,7 +27,6 @@ var good = []scryptTestVector {
 			0x87, 0x25, 0x1a, 0x53, 0x4f, 0x75, 0xac, 0xd9, 0x5a,
 			0xc5, 0xe5, 0xa, 0xa1, 0x5f,
 		},
-		nil,
 	},
 	{
 		"password",
@@ -195,7 +38,6 @@ var good = []scryptTestVector {
 			0x74, 0x82, 0x95, 0x25, 0xb1, 0x8d, 0x73, 0x23, 0xa5,
 			0x7f, 0x91, 0x96, 0x3c, 0x37,
 		},
-		nil,
 	},
 	{
 		"this is a long \000 password",
@@ -212,7 +54,6 @@ var good = []scryptTestVector {
 			0x14, 0x32, 0xbb, 0x3b, 0x6f, 0x7e, 0x12, 0x64, 0x40,
 			0x18, 0x79, 0xe6, 0x41, 0xae,
 		},
-		nil,
 	},
 	{
 		"p",
@@ -222,9 +63,7 @@ var good = []scryptTestVector {
 			0x48, 0xb0, 0xd2, 0xa8, 0xa3, 0x27, 0x26, 0x11, 0x98,
 			0x4c, 0x50, 0xeb, 0xd6, 0x30, 0xaf, 0x52,
 		},
-		nil,
 	},
-
 	{
 		"",
 		"",
@@ -239,7 +78,6 @@ var good = []scryptTestVector {
 			0x36, 0x28, 0xcf, 0x35, 0xe2, 0x0c, 0x38, 0xd1, 0x89,
 			0x06,
 		},
-		nil,
 	},
 	{
 		"password",
@@ -255,7 +93,6 @@ var good = []scryptTestVector {
 			0xee, 0x6d, 0x83, 0x60, 0xcb, 0xdf, 0xa2, 0xcc, 0x06,
 			0x40,
 		},
-		nil,
 	},
 	{
 		"pleaseletmein", "SodiumChloride",
@@ -270,7 +107,6 @@ var good = []scryptTestVector {
 			0x1e, 0x40, 0xdf, 0xcf, 0x01, 0x7b, 0x45, 0x57, 0x58,
 			0x87,
 		},
-		nil,
 	},
 	// // Disabled: needs 1 GiB RAM and takes too long for a simple test.
 	// {
@@ -286,16 +122,15 @@ var good = []scryptTestVector {
 	// 		0x52, 0xfb, 0xcb, 0xf4, 0x5c, 0x6f, 0xa7, 0x7a, 0x41,
 	// 		0xa4,
 	// 	},
-	// 	nil,
 	// },
 }
 
-const halfMax = maxInt / 2
+const halfMax = (int((^uint(0)) >> 1)) / 2
 var bad = []scryptTestVector {
-	{"p", "s", 0,  1,       1,       nil, ErrBadN},            // N == 0
-	{"p", "s", 1,  1,       1,       nil, ErrBadN},            // N == 1
-	{"p", "s", 7,  8,       1,       nil, ErrBadN},            // N is not power of 2
-	{"p", "s", 16, halfMax, halfMax, nil, ErrParamsTooLarge},  // p * r too large
+	{"p", "s", 0,  1,       1,       nil},  // N == 0
+	{"p", "s", 1,  1,       1,       nil},  // N == 1
+	{"p", "s", 7,  8,       1,       nil},  // N is not power of 2
+	{"p", "s", 16, halfMax, halfMax, nil},  // p * r too large
 }
 
 func test_scrypt() {
@@ -326,7 +161,7 @@ func test_scrypt() {
 				v.p,
 				32,
 			)
-			g.TAssertEqual(err, v.err)
+			g.TErrorNil(err)
 		}
 	})
 
@@ -354,34 +189,22 @@ func test_scrypt() {
 func test_SaltFrom() {
 	g.TestStart("SaltFrom()")
 
-	g.Testing("error when reader errors", func() {
+	g.Testing("reader error is propagated", func() {
+		r := strings.NewReader("input")
+		payload, err := SaltFrom(r)
+		g.TAssertEqual(err.Error(), "unexpected EOF")
+		g.TAssertEqual(payload, []byte(nil))
 	})
-	// FIXME
-}
-
-func test_HashFrom() {
-	g.TestStart("HashFrom()")
-	// FIXME
-}
-
-func test_CheckFrom() {
-	g.TestStart("CheckFrom()")
-	// FIXME
 }
 
 func test_Salt() {
 	g.TestStart("Salt()")
 
-	/*
 	g.Testing("we generate a random salt of a fixed size", func() {
-		salt := Salt()
-		g.TAssertEqual(len(salt), saltMinLength)
-
-		var buffer [saltMinLength * 2]byte
-		hex.Encode(buffer[:], salt)
-		// FIXME
+		salt, err := Salt()
+		g.TErrorIf(err)
+		g.TAssertEqual(len(salt), _SALT_MIN_LENGTH)
 	})
-	*/
 }
 
 func test_Hash() {
@@ -406,17 +229,69 @@ func test_Hash() {
 
 func test_Check() {
 	g.TestStart("Check()")
-	// FIXME
+
+	h := func(password []byte, salt []byte) []byte {
+		hash, err := Hash(password, salt)
+		g.TErrorIf(err)
+		return hash
+	}
+
+	chk := func(password []byte, salt []byte, hash []byte) bool {
+		ok, err := Check(password, salt, hash)
+		g.TErrorIf(err)
+		return ok
+	}
+
+
+	g.Testing("true for equal inputs", func() {
+		password1 := []byte("password")
+		password2 := []byte("passw0rd")
+		salt1     := []byte("salt0000111111112222222233333333")
+		salt2     := []byte("salt0000l11111112222222233333333")
+
+		hash1 := h(password1, salt1)
+		hash2 := h(password1, salt2)
+		hash3 := h(password2, salt1)
+		hash4 := h(password2, salt2)
+
+		given1 := []bool{
+			chk(password1, salt1, hash1),
+			chk(password1, salt2, hash2),
+			chk(password2, salt1, hash3),
+			chk(password2, salt2, hash4),
+		}
+
+		expected1 := []bool{
+			true,
+			true,
+			true,
+			true,
+		}
+
+		given2 := []bool{
+			chk(password1, salt1, hash4),
+			chk(password1, salt2, hash3),
+			chk(password2, salt1, hash2),
+			chk(password2, salt2, hash1),
+		}
+
+		expected2 := []bool{
+			false,
+			false,
+			false,
+			false,
+		}
+
+		g.TAssertEqual(given1, expected1)
+		g.TAssertEqual(given2, expected2)
+	})
 }
 
 
 
 func MainTest() {
-	test__PBKDF()
 	test_scrypt()
 	test_SaltFrom()
-	test_HashFrom()
-	test_CheckFrom()
 	test_Salt()
 	test_Hash()
 	test_Check()