MVP, no mod tools or anything but it works

vendor/gopkg.in/hlandau/passlib.v1/hash/scrypt/raw/scrypt.go

@@ -0,0 +1,95 @@
+// Package raw provides a raw implementation of the modular-crypt-wrapped scrypt primitive.
+package raw
+
+import "golang.org/x/crypto/scrypt"
+import "encoding/base64"
+import "strings"
+import "strconv"
+import "fmt"
+
+// The current recommended N value for interactive logins.
+const RecommendedN = 16384
+
+// The current recommended r value for interactive logins.
+const Recommendedr = 8
+
+// The current recommended p value for interactive logins.
+const Recommendedp = 1
+
+// Wrapper for golang.org/x/crypto/scrypt implementing a sensible
+// modular crypt interface.
+//
+// password should be a UTF-8 plaintext password.
+// salt should be a random salt value in binary form.
+//
+// N, r and p are parameters to scrypt.
+//
+// Returns a modular crypt hash.
+func ScryptSHA256(password string, salt []byte, N, r, p int) string {
+	passwordb := []byte(password)
+
+	hash, err := scrypt.Key(passwordb, salt, N, r, p, 32)
+	if err != nil {
+		panic(err)
+	}
+
+	hstr := base64.StdEncoding.EncodeToString(hash)
+	sstr := base64.StdEncoding.EncodeToString(salt)
+
+	return fmt.Sprintf("$s2$%d$%d$%d$%s$%s", N, r, p, sstr, hstr)
+}
+
+// Indicates that a password hash or stub is invalid.
+var ErrInvalidStub = fmt.Errorf("invalid scrypt password stub")
+
+// Parses an scrypt modular hash or stub string.
+//
+// The format is as follows:
+//
+//   $s2$N$r$p$salt$hash    // hash
+//   $s2$N$r$p$salt         // stub
+//
+func Parse(stub string) (salt, hash []byte, N, r, p int, err error) {
+	if len(stub) < 10 || !strings.HasPrefix(stub, "$s2$") {
+		err = ErrInvalidStub
+		return
+	}
+
+	// $s2$  N$r$p$salt-base64$hash-base64
+	parts := strings.Split(stub[4:], "$")
+
+	if len(parts) < 4 {
+		err = ErrInvalidStub
+		return
+	}
+
+	var Ni, ri, pi uint64
+
+	Ni, err = strconv.ParseUint(parts[0], 10, 31)
+	if err != nil {
+		return
+	}
+
+	ri, err = strconv.ParseUint(parts[1], 10, 31)
+	if err != nil {
+		return
+	}
+
+	pi, err = strconv.ParseUint(parts[2], 10, 31)
+	if err != nil {
+		return
+	}
+
+	N, r, p = int(Ni), int(ri), int(pi)
+
+	salt, err = base64.StdEncoding.DecodeString(parts[3])
+	if err != nil {
+		return
+	}
+
+	if len(parts) >= 5 {
+		hash, err = base64.StdEncoding.DecodeString(parts[4])
+	}
+
+	return
+}