join handler implemented

backend/Makefile

@@ -1,14 +1,27 @@
+PROJECT_DIR = $(CURDIR)
+PROJECT_BIN = ${PROJECT_DIR}/bin
+TOOLS_BIN = ${PROJECT_BIN}/tools
+
 bin.build:
-	mkdir -p build
+	mkdir -p ${PROJECT_DIR}/build
-	rm -f build/blockd
+	rm -f ${PROJECT_DIR}/build/blockd
-	go build -ldflags="-s -w" -o build/blockd cmd/main.go
+	go build -ldflags="-s -w" -o ${PROJECT_DIR}/build/blockd ${PROJECT_DIR}/cmd/main.go
 
 d.build:
 	sudo docker buildx build . -t blockd:latest
 
+d.net:
+	sudo docker network create --driver bridge --subnet=192.168.2.0/24 --attachable blockd-net
+
+d.drop-net:
+	sudo docker network rm blockd-net
+
+up:
+	sudo docker compose up -d
+
 .PHONY: run.local
 run.local: bin.build
-	./build/blockd \
+	${PROJECT_DIR}/build/blockd \
 		-log-level=debug \
 		-log-local=true \
 		-log-add-source=true \
@@ -21,7 +34,7 @@ run.local: bin.build
 
 .PHONY: run.debug
 run.debug: bin.build
-	./build/blockd \
+	${PROJECT_DIR}/build/blockd \
 		-log-level=debug \
 		-log-local=false \
 		-log-add-source=true \

backend/cmd/main.go

@@ -7,8 +7,8 @@ import (
 	"syscall"
 
 	"github.com/emochka2007/block-accounting/cmd/commands"
-	"github.com/emochka2007/block-accounting/internal/config"
 	"github.com/emochka2007/block-accounting/internal/factory"
+	"github.com/emochka2007/block-accounting/internal/pkg/config"
 
 	cli "github.com/urfave/cli/v2"
 )

backend/go.mod

@@ -5,12 +5,15 @@ go 1.22.2
 require (
 	github.com/fatih/color v1.16.0
 	github.com/go-chi/chi/v5 v5.0.12
+	github.com/go-chi/render v1.0.3
+	github.com/golang-jwt/jwt/v5 v5.2.1
 	github.com/google/wire v0.6.0
 	github.com/urfave/cli/v2 v2.27.2
-	golang.org/x/sync v0.7.0
+	golang.org/x/crypto v0.18.0
 )
 
 require (
+	github.com/ajg/form v1.5.1 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.4 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect

backend/go.sum

@@ -1,9 +1,15 @@
+github.com/ajg/form v1.5.1 h1:t9c7v8JUKu/XxOGBU0yjNpaMloxGEJhUkqFRq0ibGeU=
+github.com/ajg/form v1.5.1/go.mod h1:uL1WgH+h2mgNtvBq0339dVnzXdBETtL2LeUXaIv25UY=
 github.com/cpuguy83/go-md2man/v2 v2.0.4 h1:wfIWP927BUkWJb2NmU/kNDYIBTh/ziUX91+lVfRxZq4=
 github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/fatih/color v1.16.0 h1:zmkK9Ngbjj+K0yRhTVONQh1p/HknKYSlNT+vZCzyokM=
 github.com/fatih/color v1.16.0/go.mod h1:fL2Sau1YI5c0pdGEVCbKQbLXB6edEj1ZgiY4NijnWvE=
 github.com/go-chi/chi/v5 v5.0.12 h1:9euLV5sTrTNTRUU9POmDUvfxyj6LAABLUcEWO+JJb4s=
 github.com/go-chi/chi/v5 v5.0.12/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
+github.com/go-chi/render v1.0.3 h1:AsXqd2a1/INaIfUSKq3G5uA8weYx20FOsM7uSoCyyt4=
+github.com/go-chi/render v1.0.3/go.mod h1:/gr3hVkmYR0YlEy3LxCuVRFzEu9Ruok+gFqbIofjao0=
+github.com/golang-jwt/jwt/v5 v5.2.1 h1:OuVbFODueb089Lh128TAcimifWaLhJwVflnrgM17wHk=
+github.com/golang-jwt/jwt/v5 v5.2.1/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/subcommands v1.2.0/go.mod h1:ZjhPrFU+Olkh9WazFPsl27BQ4UPiG37m3yTrtFlrHVk=
 github.com/google/wire v0.6.0 h1:HBkoIh4BdSxoyo9PveV8giw7ZsaBOvzWKfcg/6MrVwI=
@@ -24,6 +30,7 @@ github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5t
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
+golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
 golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
@@ -41,8 +48,6 @@ golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
-golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

backend/internal/factory/service.go

@@ -7,10 +7,11 @@ import (
 	"log/slog"
 	"os"
 
-	"github.com/emochka2007/block-accounting/internal/config"
-	"github.com/emochka2007/block-accounting/internal/interface/controllers"
 	"github.com/emochka2007/block-accounting/internal/interface/rest"
-	"github.com/emochka2007/block-accounting/internal/logger"
+	"github.com/emochka2007/block-accounting/internal/interface/rest/controllers"
+	"github.com/emochka2007/block-accounting/internal/interface/rest/presenters"
+	"github.com/emochka2007/block-accounting/internal/pkg/config"
+	"github.com/emochka2007/block-accounting/internal/pkg/logger"
 	"github.com/emochka2007/block-accounting/internal/service"
 	"github.com/google/wire"
 )
@@ -54,6 +55,10 @@ func provideControllers(
 ) *controllers.RootController {
 	return &controllers.RootController{
 		Ping: controllers.NewPingController(log.WithGroup("ping-controller")),
+		Auth: controllers.NewAuthController(
+			log.WithGroup("auth-controller"),
+			presenters.NewAuthPresenter(),
+		),
 	}
 }
 

backend/internal/factory/wire_gen.go

@@ -7,10 +7,11 @@
 package factory
 
 import (
-	"github.com/emochka2007/block-accounting/internal/config"
-	"github.com/emochka2007/block-accounting/internal/interface/controllers"
 	"github.com/emochka2007/block-accounting/internal/interface/rest"
-	"github.com/emochka2007/block-accounting/internal/logger"
+	"github.com/emochka2007/block-accounting/internal/interface/rest/controllers"
+	"github.com/emochka2007/block-accounting/internal/interface/rest/presenters"
+	"github.com/emochka2007/block-accounting/internal/pkg/config"
+	"github.com/emochka2007/block-accounting/internal/pkg/logger"
 	"github.com/emochka2007/block-accounting/internal/service"
 	"log/slog"
 	"os"
@@ -57,6 +58,9 @@ func provideControllers(
 ) *controllers.RootController {
 	return &controllers.RootController{
 		Ping: controllers.NewPingController(log.WithGroup("ping-controller")),
+		Auth: controllers.NewAuthController(
+			log.WithGroup("auth-controller"), presenters.NewAuthPresenter(),
+		),
 	}
 }
 

backend/internal/interface/rest/controllers/auth.go

@@ -0,0 +1,72 @@
+package controllers
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+
+	"github.com/emochka2007/block-accounting/internal/interface/rest/domain"
+	"github.com/emochka2007/block-accounting/internal/interface/rest/presenters"
+	"github.com/emochka2007/block-accounting/internal/pkg/bip32"
+)
+
+type AuthController interface {
+	Join(w http.ResponseWriter, req *http.Request) error
+	Login(w http.ResponseWriter, req *http.Request) error
+	Invite(w http.ResponseWriter, req *http.Request) error
+}
+
+type authController struct {
+	log       *slog.Logger
+	presenter presenters.AuthPresenter
+	// interactors ...
+}
+
+func NewAuthController(
+	log *slog.Logger,
+	presenter presenters.AuthPresenter,
+) AuthController {
+	return &authController{
+		log:       log,
+		presenter: presenter,
+	}
+}
+
+const mnemonicEntropyBitSize int = 256
+
+func (c *authController) Join(w http.ResponseWriter, req *http.Request) error {
+	entropy, err := bip32.NewEntropy(mnemonicEntropyBitSize)
+	if err != nil {
+		return fmt.Errorf("error generate new entropy. %w", err)
+	}
+
+	mnemonic, err := bip32.NewMnemonic(entropy)
+	if err != nil {
+		return fmt.Errorf("error generate mnemonic from entropy. %w", err)
+	}
+
+	// todo create user
+
+	// move to presenter
+	out, err := json.Marshal(domain.JoinResponse{
+		Mnemonic: mnemonic,
+	})
+	if err != nil {
+		return fmt.Errorf("error marshal join response. %w", err)
+	}
+
+	w.Write(out)
+
+	// move to presenter
+
+	return nil
+}
+
+func (c *authController) Login(w http.ResponseWriter, req *http.Request) error {
+	return nil // implement
+}
+
+func (c *authController) Invite(w http.ResponseWriter, req *http.Request) error {
+	return nil // implement
+}

backend/internal/interface/rest/controllers/ping.go

@@ -1,13 +1,12 @@
 package controllers
 
 import (
-	"context"
 	"log/slog"
 	"net/http"
 )
 
 type PingController interface {
-	HandlePing(ctx context.Context, req *http.Request, w http.ResponseWriter) error
+	Ping(w http.ResponseWriter, req *http.Request) error
 }
 
 type pingController struct {
@@ -22,7 +21,7 @@ func NewPingController(
 	}
 }
 
-func (c *pingController) HandlePing(ctx context.Context, req *http.Request, w http.ResponseWriter) error {
+func (c *pingController) Ping(w http.ResponseWriter, req *http.Request) error {
 	_, err := w.Write([]byte("pong"))
 
 	return err

backend/internal/interface/rest/controllers/root.go

@@ -2,12 +2,15 @@ package controllers
 
 type RootController struct {
 	Ping PingController
+	Auth AuthController
 }
 
 func NewRootController(
 	ping PingController,
+	auth AuthController,
 ) *RootController {
 	return &RootController{
 		Ping: ping,
+		Auth: auth,
 	}
 }

backend/internal/interface/rest/domain/dto.go

@@ -0,0 +1,20 @@
+package domain
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type JoinResponse struct {
+	Mnemonic string `json:"mnemonic"`
+}
+
+func BuildRequest[T any](data []byte) (*T, error) {
+	var req T
+
+	if err := json.Unmarshal(data, &req); err != nil {
+		return nil, fmt.Errorf("error unmarshal request. %w", err)
+	}
+
+	return &req, nil
+}

backend/internal/interface/rest/presenters/auth.go

@@ -0,0 +1,34 @@
+package presenters
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"github.com/emochka2007/block-accounting/internal/interface/rest/domain"
+)
+
+type AuthPresenter interface {
+	ResponseJoin(w http.ResponseWriter, mnemonic string) error
+}
+
+type authPresenter struct{}
+
+func NewAuthPresenter() AuthPresenter {
+	return &authPresenter{}
+}
+
+func (p *authPresenter) ResponseJoin(w http.ResponseWriter, mnemonic string) error {
+	out, err := json.Marshal(domain.JoinResponse{
+		Mnemonic: mnemonic,
+	})
+	if err != nil {
+		return fmt.Errorf("error marshal join response. %w", err)
+	}
+
+	if _, err = w.Write(out); err != nil {
+		return fmt.Errorf("error write response. %w", err)
+	}
+
+	return nil
+}

backend/internal/interface/rest/server.go

@@ -7,11 +7,12 @@ import (
 	"net/http"
 	"sync"
 
-	"github.com/emochka2007/block-accounting/internal/config"
+	"github.com/emochka2007/block-accounting/internal/interface/rest/controllers"
-	"github.com/emochka2007/block-accounting/internal/interface/controllers"
+	"github.com/emochka2007/block-accounting/internal/pkg/config"
-	"github.com/emochka2007/block-accounting/internal/logger"
+	"github.com/emochka2007/block-accounting/internal/pkg/logger"
 	"github.com/go-chi/chi/v5"
 	mw "github.com/go-chi/chi/v5/middleware"
+	"github.com/go-chi/render"
 )
 
 type Server struct {
@@ -63,23 +64,25 @@ func (s *Server) Serve(ctx context.Context) error {
 
 func (s *Server) Close() {
 	s.closeMu.Lock()
-	defer s.closeMu.Unlock()
 
 	s.closed = true
+
+	s.closeMu.Unlock()
 }
 
 func (s *Server) buildRouter() {
 	s.Mux = chi.NewRouter()
 
-	s.With(mw.Recoverer)
+	s.Use(mw.Recoverer)
-	s.With(mw.RequestID)
+	s.Use(mw.RequestID)
-	s.With(s.handleMw)
+	s.Use(s.handleMw)
+	s.Use(render.SetContentType(render.ContentTypeJSON))
 
 	s.Get("/ping", s.handlePing) // debug
 
 	// auth
-	s.Post("/join", nil)  // new user
+	s.Post("/join", s.handleJoin) // new user
-	s.Post("/login", nil) // login
+	s.Post("/login", nil)         // login
 
 	s.Route("/organization/{organization_id}", func(r chi.Router) {
 		s.Route("/transactions", func(r chi.Router) {
@@ -118,22 +121,30 @@ func (s *Server) responseError(w http.ResponseWriter, e error) {
 func (s *Server) handleMw(next http.Handler) http.Handler {
 	fn := func(w http.ResponseWriter, r *http.Request) {
 		s.closeMu.RLock()
-		defer s.closeMu.Unlock()
+		defer s.closeMu.RUnlock()
 
 		if s.closed { // keep mutex closed
 			return
 		}
 
+		w.Header().Add("Content-Type", "application/json")
+
 		next.ServeHTTP(w, r)
 	}
 
 	return http.HandlerFunc(fn)
 }
 
-func (s *Server) handlePing(w http.ResponseWriter, req *http.Request) {
+func (s *Server) handleJoin(w http.ResponseWriter, req *http.Request) {
-	s.log.Debug("ping request")
+	if err := s.controllers.Auth.Join(w, req); err != nil {
-
+		s.responseError(w, err)
-	if err := s.controllers.Ping.HandlePing(s.ctx, req, w); err != nil {
+	}
+}
+
+func (s *Server) handlePing(w http.ResponseWriter, req *http.Request) {
+	s.log.Debug("ping request")
+
+	if err := s.controllers.Ping.Ping(w, req); err != nil {
 		s.responseError(w, err)
 	}
 }

backend/internal/pkg/bip32/bip32.go

@@ -0,0 +1,348 @@
+package bip32
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math/big"
+	"strings"
+
+	"golang.org/x/crypto/pbkdf2"
+)
+
+var (
+	// Some bitwise operands for working with big.Ints.
+	last11BitsMask  = big.NewInt(2047)
+	shift11BitsMask = big.NewInt(2048)
+	bigOne          = big.NewInt(1)
+	bigTwo          = big.NewInt(2)
+
+	// wordLengthChecksumMasksMapping is used to isolate the checksum bits from
+	//the entropy+checksum byte array.
+	wordLengthChecksumMasksMapping = map[int]*big.Int{
+		12: big.NewInt(15),
+		15: big.NewInt(31),
+		18: big.NewInt(63),
+		21: big.NewInt(127),
+		24: big.NewInt(255),
+	}
+
+	// wordLengthChecksumShiftMapping is used to lookup the number of operand
+	// for shifting bits to handle checksums.
+	wordLengthChecksumShiftMapping = map[int]*big.Int{
+		12: big.NewInt(16),
+		15: big.NewInt(8),
+		18: big.NewInt(4),
+		21: big.NewInt(2),
+	}
+
+	// wordList is the set of words to use.
+	wordList []string
+
+	// wordMap is a reverse lookup map for wordList.
+	wordMap map[string]int
+)
+
+var (
+	// ErrInvalidMnemonic is returned when trying to use a malformed mnemonic.
+	ErrInvalidMnemonic = errors.New("Invalid mnenomic")
+
+	// ErrEntropyLengthInvalid is returned when trying to use an entropy set with
+	// an invalid size.
+	ErrEntropyLengthInvalid = errors.New("Entropy length must be [128, 256] and a multiple of 32")
+
+	// ErrValidatedSeedLengthMismatch is returned when a validated seed is not the
+	// same size as the given seed. This should never happen is present only as a
+	// sanity assertion.
+	ErrValidatedSeedLengthMismatch = errors.New("Seed length does not match validated seed length")
+
+	// ErrChecksumIncorrect is returned when entropy has the incorrect checksum.
+	ErrChecksumIncorrect = errors.New("Checksum incorrect")
+)
+
+func init() {
+	SetWordList(English)
+}
+
+// SetWordList sets the list of words to use for mnemonics. Currently the list
+// that is set is used package-wide.
+func SetWordList(list []string) {
+	wordList = list
+	wordMap = map[string]int{}
+
+	for i, v := range wordList {
+		wordMap[v] = i
+	}
+}
+
+// GetWordList gets the list of words to use for mnemonics.
+func GetWordList() []string {
+	return wordList
+}
+
+// GetWordIndex gets word index in wordMap.
+func GetWordIndex(word string) (int, bool) {
+	idx, ok := wordMap[word]
+	return idx, ok
+}
+
+// NewEntropy will create random entropy bytes
+// so long as the requested size bitSize is an appropriate size.
+//
+// bitSize has to be a multiple 32 and be within the inclusive range of {128, 256}.
+func NewEntropy(bitSize int) ([]byte, error) {
+	if err := validateEntropyBitSize(bitSize); err != nil {
+		return nil, err
+	}
+
+	entropy := make([]byte, bitSize/8)
+	_, _ = rand.Read(entropy) // err is always nil
+
+	return entropy, nil
+}
+
+// EntropyFromMnemonic takes a mnemonic generated by this library,
+// and returns the input entropy used to generate the given mnemonic.
+// An error is returned if the given mnemonic is invalid.
+func EntropyFromMnemonic(mnemonic string) ([]byte, error) {
+	mnemonicSlice, isValid := splitMnemonicWords(mnemonic)
+	if !isValid {
+		return nil, ErrInvalidMnemonic
+	}
+
+	// Decode the words into a big.Int.
+	var (
+		wordBytes [2]byte
+		b         = big.NewInt(0)
+	)
+
+	for _, v := range mnemonicSlice {
+		index, found := wordMap[v]
+		if !found {
+			return nil, fmt.Errorf("word `%v` not found in reverse map", v)
+		}
+
+		binary.BigEndian.PutUint16(wordBytes[:], uint16(index))
+		b.Mul(b, shift11BitsMask)
+		b.Or(b, big.NewInt(0).SetBytes(wordBytes[:]))
+	}
+
+	// Build and add the checksum to the big.Int.
+	checksum := big.NewInt(0)
+	checksumMask := wordLengthChecksumMasksMapping[len(mnemonicSlice)]
+	checksum = checksum.And(b, checksumMask)
+
+	b.Div(b, big.NewInt(0).Add(checksumMask, bigOne))
+
+	// The entropy is the underlying bytes of the big.Int. Any upper bytes of
+	// all 0's are not returned so we pad the beginning of the slice with empty
+	// bytes if necessary.
+	entropy := b.Bytes()
+	entropy = padByteSlice(entropy, len(mnemonicSlice)/3*4)
+
+	// Generate the checksum and compare with the one we got from the mneomnic.
+	entropyChecksumBytes := computeChecksum(entropy)
+	entropyChecksum := big.NewInt(int64(entropyChecksumBytes[0]))
+
+	if l := len(mnemonicSlice); l != 24 {
+		checksumShift := wordLengthChecksumShiftMapping[l]
+		entropyChecksum.Div(entropyChecksum, checksumShift)
+	}
+
+	if checksum.Cmp(entropyChecksum) != 0 {
+		return nil, ErrChecksumIncorrect
+	}
+
+	return entropy, nil
+}
+
+// NewMnemonic will return a string consisting of the mnemonic words for
+// the given entropy.
+// If the provide entropy is invalid, an error will be returned.
+func NewMnemonic(entropy []byte) (string, error) {
+	// Compute some lengths for convenience.
+	entropyBitLength := len(entropy) * 8
+	checksumBitLength := entropyBitLength / 32
+	sentenceLength := (entropyBitLength + checksumBitLength) / 11
+
+	// Validate that the requested size is supported.
+	err := validateEntropyBitSize(entropyBitLength)
+	if err != nil {
+		return "", err
+	}
+
+	// Add checksum to entropy.
+	entropy = addChecksum(entropy)
+
+	// Break entropy up into sentenceLength chunks of 11 bits.
+	// For each word AND mask the rightmost 11 bits and find the word at that index.
+	// Then bitshift entropy 11 bits right and repeat.
+	// Add to the last empty slot so we can work with LSBs instead of MSB.
+
+	// Entropy as an int so we can bitmask without worrying about bytes slices.
+	entropyInt := new(big.Int).SetBytes(entropy)
+
+	// Slice to hold words in.
+	words := make([]string, sentenceLength)
+
+	// Throw away big.Int for AND masking.
+	word := big.NewInt(0)
+
+	for i := sentenceLength - 1; i >= 0; i-- {
+		// Get 11 right most bits and bitshift 11 to the right for next time.
+		word.And(entropyInt, last11BitsMask)
+		entropyInt.Div(entropyInt, shift11BitsMask)
+
+		// Get the bytes representing the 11 bits as a 2 byte slice.
+		wordBytes := padByteSlice(word.Bytes(), 2)
+
+		// Convert bytes to an index and add that word to the list.
+		words[i] = wordList[binary.BigEndian.Uint16(wordBytes)]
+	}
+
+	return strings.Join(words, " "), nil
+}
+
+// MnemonicToByteArray takes a mnemonic string and turns it into a byte array
+// suitable for creating another mnemonic.
+// An error is returned if the mnemonic is invalid.
+func MnemonicToByteArray(mnemonic string, raw ...bool) ([]byte, error) {
+	var (
+		mnemonicSlice   = strings.Split(mnemonic, " ")
+		entropyBitSize  = len(mnemonicSlice) * 11
+		checksumBitSize = entropyBitSize % 32
+		fullByteSize    = (entropyBitSize-checksumBitSize)/8 + 1
+	)
+
+	// Turn into raw entropy.
+	rawEntropyBytes, err := EntropyFromMnemonic(mnemonic)
+	if err != nil {
+		return nil, err
+	}
+
+	// If we want the raw entropy then we're done.
+	if len(raw) > 0 && raw[0] {
+		return rawEntropyBytes, nil
+	}
+
+	// Otherwise add the checksum before returning
+	return padByteSlice(addChecksum(rawEntropyBytes), fullByteSize), nil
+}
+
+// NewSeedWithErrorChecking creates a hashed seed output given the mnemonic string and a password.
+// An error is returned if the mnemonic is not convertible to a byte array.
+func NewSeedWithErrorChecking(mnemonic string, password string) ([]byte, error) {
+	_, err := MnemonicToByteArray(mnemonic)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewSeed(mnemonic, password), nil
+}
+
+// NewSeed creates a hashed seed output given a provided string and password.
+// No checking is performed to validate that the string provided is a valid mnemonic.
+func NewSeed(mnemonic string, password string) []byte {
+	return pbkdf2.Key([]byte(mnemonic), []byte("mnemonic"+password), 2048, 64, sha512.New)
+}
+
+// IsMnemonicValid attempts to verify that the provided mnemonic is valid.
+// Validity is determined by both the number of words being appropriate,
+// and that all the words in the mnemonic are present in the word list.
+func IsMnemonicValid(mnemonic string) bool {
+	_, err := EntropyFromMnemonic(mnemonic)
+	return err == nil
+}
+
+// Appends to data the first (len(data) / 32)bits of the result of sha256(data)
+// Currently only supports data up to 32 bytes.
+func addChecksum(data []byte) []byte {
+	// Get first byte of sha256
+	hash := computeChecksum(data)
+	firstChecksumByte := hash[0]
+
+	// len() is in bytes so we divide by 4
+	checksumBitLength := uint(len(data) / 4)
+
+	// For each bit of check sum we want we shift the data one the left
+	// and then set the (new) right most bit equal to checksum bit at that index
+	// staring from the left
+	dataBigInt := new(big.Int).SetBytes(data)
+
+	for i := uint(0); i < checksumBitLength; i++ {
+		// Bitshift 1 left
+		dataBigInt.Mul(dataBigInt, bigTwo)
+
+		// Set rightmost bit if leftmost checksum bit is set
+		if firstChecksumByte&(1<<(7-i)) > 0 {
+			dataBigInt.Or(dataBigInt, bigOne)
+		}
+	}
+
+	return dataBigInt.Bytes()
+}
+
+func computeChecksum(data []byte) []byte {
+	hasher := sha256.New()
+	_, _ = hasher.Write(data) // This error is guaranteed to be nil
+
+	return hasher.Sum(nil)
+}
+
+// validateEntropyBitSize ensures that entropy is the correct size for being a
+// mnemonic.
+func validateEntropyBitSize(bitSize int) error {
+	if (bitSize%32) != 0 || bitSize < 128 || bitSize > 256 {
+		return ErrEntropyLengthInvalid
+	}
+
+	return nil
+}
+
+// padByteSlice returns a byte slice of the given size with contents of the
+// given slice left padded and any empty spaces filled with 0's.
+func padByteSlice(slice []byte, length int) []byte {
+	offset := length - len(slice)
+	if offset <= 0 {
+		return slice
+	}
+
+	newSlice := make([]byte, length)
+	copy(newSlice[offset:], slice)
+
+	return newSlice
+}
+
+// compareByteSlices returns true of the byte slices have equal contents and
+// returns false otherwise.
+func compareByteSlices(a, b []byte) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+func splitMnemonicWords(mnemonic string) ([]string, bool) {
+	// Create a list of all the words in the mnemonic sentence
+	words := strings.Fields(mnemonic)
+
+	// Get num of words
+	numOfWords := len(words)
+
+	// The number of words should be 12, 15, 18, 21 or 24
+	if numOfWords%3 != 0 || numOfWords < 12 || numOfWords > 24 {
+		return nil, false
+	}
+
+	return words, true
+}

backend/internal/pkg/models/user.go

@@ -0,0 +1,6 @@
+package models
+
+type UserIdentity interface {
+	Id() string
+	Mnemonic() string
+}

backend/internal/service/service.go

@@ -43,6 +43,8 @@ func (s *ServiceImpl) Run(ctx context.Context) error {
 
 	select {
 	case <-ctx.Done():
+		s.log.Info("shutting down service")
+
 		return nil
 	case err := <-errch:
 		return fmt.Errorf("error at service runtime. %w", err)

backend/internal/usecase/interactors/jwt/jwt.go

@@ -0,0 +1,39 @@
+package jwt
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/emochka2007/block-accounting/internal/pkg/models"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type JWTInteractor interface {
+	NewToken(user models.UserIdentity, duration time.Duration) (string, error)
+}
+
+type jwtInteractor struct {
+	secret []byte
+}
+
+func NewWardenJWT(secret []byte) JWTInteractor {
+	return &jwtInteractor{secret}
+}
+
+// NewToken creates new JWT token for given user
+func (w *jwtInteractor) NewToken(user models.UserIdentity, duration time.Duration) (string, error) {
+	token := jwt.New(jwt.SigningMethodHS256)
+
+	claims := token.Claims.(jwt.MapClaims)
+	claims["uid"] = user.Id()
+	claims["exp"] = time.Now().Add(duration).Unix()
+
+	secret := w.secret
+
+	tokenString, err := token.SignedString([]byte(secret))
+	if err != nil {
+		return "", fmt.Errorf("error sign token. %w", err)
+	}
+
+	return tokenString, nil
+}