diff --git a/.deadcode-out b/.deadcode-out
deleted file mode 100644
index d973769997..0000000000
--- a/.deadcode-out
+++ /dev/null
@@ -1,365 +0,0 @@
-package "code.gitea.io/gitea/cmd"
-	func NoMainListener
-
-package "code.gitea.io/gitea/cmd/forgejo"
-	func ContextSetNoInit
-	func ContextSetNoExit
-	func ContextSetStderr
-	func ContextGetStderr
-	func ContextSetStdout
-	func ContextSetStdin
-
-package "code.gitea.io/gitea/models"
-	func IsErrUpdateTaskNotExist
-	func (ErrUpdateTaskNotExist).Error
-	func (ErrUpdateTaskNotExist).Unwrap
-	func IsErrSHANotFound
-	func GetYamlFixturesAccess
-
-package "code.gitea.io/gitea/models/actions"
-	func ListUploadedArtifactsByRunID
-	func CountRunJobs
-	func (ScheduleList).GetUserIDs
-	func (ScheduleList).GetRepoIDs
-	func (ScheduleList).LoadTriggerUser
-	func (ScheduleList).LoadRepos
-	func FindSchedules
-	func CountSpecs
-	func GetVariableByID
-
-package "code.gitea.io/gitea/models/asymkey"
-	func HasDeployKey
-
-package "code.gitea.io/gitea/models/auth"
-	func GetSourceByName
-	func GetWebAuthnCredentialByID
-	func WebAuthnCredentials
-
-package "code.gitea.io/gitea/models/db"
-	func TruncateBeans
-	func InTransaction
-	func DumpTables
-	func Count
-	func FindAndCount
-
-package "code.gitea.io/gitea/models/dbfs"
-	func (*file).renameTo
-	func Create
-	func Rename
-
-package "code.gitea.io/gitea/models/forgejo/semver"
-	func GetVersion
-	func SetVersionString
-	func SetVersion
-
-package "code.gitea.io/gitea/models/forgejo_migrations"
-	func GetCurrentDBVersion
-	func EnsureUpToDate
-
-package "code.gitea.io/gitea/models/git"
-	func RemoveDeletedBranchByID
-
-package "code.gitea.io/gitea/models/issues"
-	func IsErrUnknownDependencyType
-	func (ErrNewIssueInsert).Error
-	func IsErrIssueWasClosed
-	func GetIssueWithAttrsByID
-	func GetRepoIDsForIssuesOptions
-	func GetLabelIDsInOrgByNames
-	func ChangeMilestoneStatus
-	func GetMilestonesByRepoIDs
-	func CountMilestonesByRepoCond
-	func GetMilestonesStatsByRepoCond
-	func IsErrErrPullRequestHeadRepoMissing
-	func (ErrPullRequestHeadRepoMissing).Error
-	func GetPullRequestsByHeadBranch
-	func (ErrIssueStopwatchAlreadyExist).Error
-	func (ErrIssueStopwatchAlreadyExist).Unwrap
-
-package "code.gitea.io/gitea/models/migrations/base"
-	func removeAllWithRetry
-	func newXORMEngine
-	func deleteDB
-	func PrepareTestEnv
-	func MainTest
-
-package "code.gitea.io/gitea/models/organization"
-	func UpdateTeamUnits
-	func (SearchMembersOptions).ToConds
-	func UsersInTeamsCount
-
-package "code.gitea.io/gitea/models/packages/alpine"
-	func GetBranches
-	func GetRepositories
-	func GetArchitectures
-
-package "code.gitea.io/gitea/models/perm/access"
-	func GetRepoWriters
-
-package "code.gitea.io/gitea/models/project"
-	func UpdateBoardSorting
-	func ChangeProjectStatus
-
-package "code.gitea.io/gitea/models/repo"
-	func DeleteAttachmentsByIssue
-	func (*releaseSorter).Len
-	func (*releaseSorter).Less
-	func (*releaseSorter).Swap
-	func SortReleases
-	func (SearchOrderBy).String
-	func IsErrTopicNotExist
-	func (ErrTopicNotExist).Error
-	func (ErrTopicNotExist).Unwrap
-	func GetTopicByName
-	func WatchRepoMode
-
-package "code.gitea.io/gitea/models/system"
-	func DeleteNotice
-
-package "code.gitea.io/gitea/models/unittest"
-	func CheckConsistencyFor
-	func checkForConsistency
-	func GetXORMEngine
-	func OverrideFixtures
-	func InitFixtures
-	func LoadFixtures
-	func Copy
-	func CopyDir
-	func FixturesDir
-	func fatalTestError
-	func InitSettings
-	func MainTest
-	func CreateTestEngine
-	func PrepareTestDatabase
-	func PrepareTestEnv
-	func Cond
-	func OrderBy
-	func LoadBeanIfExists
-	func BeanExists
-	func AssertExistsAndLoadBean
-	func GetCount
-	func AssertNotExistsBean
-	func AssertExistsIf
-	func AssertSuccessfulInsert
-	func AssertCount
-	func AssertInt64InRange
-
-package "code.gitea.io/gitea/models/user"
-	func IsErrPrimaryEmailCannotDelete
-	func (ErrUserInactive).Error
-	func (ErrUserInactive).Unwrap
-	func IsErrExternalLoginUserAlreadyExist
-	func IsErrExternalLoginUserNotExist
-	func IsErrUserSettingIsNotExist
-	func GetUserAllSettings
-	func DeleteUserSetting
-	func GetUserEmailsByNames
-
-package "code.gitea.io/gitea/modules/activitypub"
-	func CurrentTime
-	func containsRequiredHTTPHeaders
-	func NewClient
-	func (*Client).NewRequest
-	func (*Client).Post
-	func GetPrivateKey
-
-package "code.gitea.io/gitea/modules/assetfs"
-	func Bindata
-
-package "code.gitea.io/gitea/modules/auth/password/hash"
-	func (*DummyHasher).HashWithSaltBytes
-	func NewDummyHasher
-
-package "code.gitea.io/gitea/modules/auth/password/pwn"
-	func WithHTTP
-
-package "code.gitea.io/gitea/modules/base"
-	func BasicAuthEncode
-	func IsLetter
-	func SetupGiteaRoot
-
-package "code.gitea.io/gitea/modules/cache"
-	func GetInt
-	func WithNoCacheContext
-	func RemoveContextData
-
-package "code.gitea.io/gitea/modules/charset"
-	func (*BreakWriter).Write
-	func ToUTF8
-	func EscapeControlString
-
-package "code.gitea.io/gitea/modules/context"
-	func GetPrivateContext
-
-package "code.gitea.io/gitea/modules/emoji"
-	func ReplaceCodes
-
-package "code.gitea.io/gitea/modules/eventsource"
-	func (*Event).String
-
-package "code.gitea.io/gitea/modules/git"
-	func AllowLFSFiltersArgs
-	func AddChanges
-	func AddChangesWithArgs
-	func CommitChanges
-	func CommitChangesWithArgs
-	func IsErrExecTimeout
-	func (ErrExecTimeout).Error
-	func (ErrUnsupportedVersion).Error
-	func SetUpdateHook
-	func openRepositoryWithDefaultContext
-	func GetBranchCommitID
-	func IsTagExist
-	func ToEntryMode
-	func (*LimitedReaderCloser).Read
-	func (*LimitedReaderCloser).Close
-
-package "code.gitea.io/gitea/modules/gitgraph"
-	func (*Parser).Reset
-
-package "code.gitea.io/gitea/modules/graceful"
-	func (*Manager).TerminateContext
-	func (*Manager).IsTerminate
-	func (*Manager).Err
-	func (*Manager).Value
-	func (*Manager).Deadline
-
-package "code.gitea.io/gitea/modules/hcaptcha"
-	func WithHTTP
-
-package "code.gitea.io/gitea/modules/json"
-	func (StdJSON).Marshal
-	func (StdJSON).Unmarshal
-	func (StdJSON).NewEncoder
-	func (StdJSON).NewDecoder
-	func (StdJSON).Indent
-
-package "code.gitea.io/gitea/modules/markup"
-	func GetRendererByType
-	func RenderString
-	func IsMarkupFile
-
-package "code.gitea.io/gitea/modules/markup/console"
-	func Render
-	func RenderString
-
-package "code.gitea.io/gitea/modules/markup/markdown"
-	func IsDetails
-	func IsSummary
-	func IsTaskCheckBoxListItem
-	func IsIcon
-	func IsColorPreview
-	func RenderRawString
-
-package "code.gitea.io/gitea/modules/markup/markdown/math"
-	func WithInlineDollarParser
-	func WithBlockDollarParser
-
-package "code.gitea.io/gitea/modules/markup/mdstripper"
-	func StripMarkdown
-
-package "code.gitea.io/gitea/modules/markup/orgmode"
-	func RenderString
-
-package "code.gitea.io/gitea/modules/private"
-	func ActionsRunnerRegister
-
-package "code.gitea.io/gitea/modules/process"
-	func (*Manager).ExecTimeout
-
-package "code.gitea.io/gitea/modules/queue"
-	func newBaseChannelSimple
-	func newBaseChannelUnique
-	func newBaseRedisSimple
-	func newBaseRedisUnique
-	func newWorkerPoolQueueForTest
-
-package "code.gitea.io/gitea/modules/queue/lqinternal"
-	func QueueItemIDBytes
-	func QueueItemKeyBytes
-	func ListLevelQueueKeys
-
-package "code.gitea.io/gitea/modules/setting"
-	func NewConfigProviderFromData
-	func (*GitConfigType).GetOption
-	func InitLoggersForTest
-
-package "code.gitea.io/gitea/modules/storage"
-	func (ErrInvalidConfiguration).Error
-	func IsErrInvalidConfiguration
-
-package "code.gitea.io/gitea/modules/structs"
-	func ParseCreateHook
-	func ParsePushHook
-
-package "code.gitea.io/gitea/modules/sync"
-	func (*StatusTable).Start
-	func (*StatusTable).IsRunning
-
-package "code.gitea.io/gitea/modules/testlogger"
-	func (*testLoggerWriterCloser).pushT
-	func (*testLoggerWriterCloser).Write
-	func (*testLoggerWriterCloser).popT
-	func (*testLoggerWriterCloser).Close
-	func (*testLoggerWriterCloser).Reset
-	func PrintCurrentTest
-	func Printf
-	func NewTestLoggerWriter
-
-package "code.gitea.io/gitea/modules/timeutil"
-	func GetExecutableModTime
-	func Set
-	func Unset
-
-package "code.gitea.io/gitea/modules/translation"
-	func (MockLocale).Language
-	func (MockLocale).Tr
-	func (MockLocale).TrN
-	func (MockLocale).PrettyNumber
-
-package "code.gitea.io/gitea/modules/util/filebuffer"
-	func CreateFromReader
-
-package "code.gitea.io/gitea/modules/web"
-	func RouteMock
-	func RouteMockReset
-
-package "code.gitea.io/gitea/modules/web/middleware"
-	func DeleteLocaleCookie
-
-package "code.gitea.io/gitea/routers/web"
-	func NotFound
-
-package "code.gitea.io/gitea/routers/web/org"
-	func MustEnableProjects
-	func getActionIssues
-	func UpdateIssueProject
-
-package "code.gitea.io/gitea/services/convert"
-	func ToSecret
-
-package "code.gitea.io/gitea/services/forms"
-	func (*DeadlineForm).Validate
-
-package "code.gitea.io/gitea/services/packages/alpine"
-	func BuildAllRepositoryFiles
-
-package "code.gitea.io/gitea/services/pull"
-	func IsCommitStatusContextSuccess
-
-package "code.gitea.io/gitea/services/repository"
-	func GetBranchCommitID
-	func IsErrForkAlreadyExist
-
-package "code.gitea.io/gitea/services/repository/archiver"
-	func ArchiveRepository
-
-package "code.gitea.io/gitea/services/repository/files"
-	func (*ContentType).String
-	func GetFileResponseFromCommit
-	func (*TemporaryUploadRepository).GetLastCommit
-	func (*TemporaryUploadRepository).GetLastCommitByRef
-
-package "code.gitea.io/gitea/services/webhook"
-	func NewNotifier
-
diff --git a/.gitignore b/.gitignore
index 3a63eed069..929253d310 100644
--- a/.gitignore
+++ b/.gitignore
@@ -99,7 +99,6 @@ cpu.out
 /VERSION
 /.air
 /.go-licenses
-/.cur-deadcode-out
 
 # Snapcraft
 /gitea_a*.txt
diff --git a/Makefile b/Makefile
index d9582737ec..35cc53ef64 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,6 @@ GO ?= go
 SHASUM ?= shasum -a 256
 HAS_GO := $(shell hash $(GO) > /dev/null 2>&1 && echo yes)
 COMMA := ,
-DIFF ?= diff --unified
 
 XGO_VERSION := go-1.21.x
 
@@ -37,7 +36,6 @@ XGO_PACKAGE ?= src.techknowlogick.com/xgo@latest
 GO_LICENSES_PACKAGE ?= github.com/google/go-licenses@v1.6.0
 GOVULNCHECK_PACKAGE ?= golang.org/x/vuln/cmd/govulncheck@v1.0.1
 ACTIONLINT_PACKAGE ?= github.com/rhysd/actionlint/cmd/actionlint@v1.6.25
-DEADCODE_PACKAGE ?= golang.org/x/tools/internal/cmd/deadcode@v0.14.0
 
 DOCKER_IMAGE ?= gitea/gitea
 DOCKER_TAG ?= latest
@@ -411,17 +409,10 @@ lint-md: node_modules
 .PHONY: lint-go
 lint-go:
 	$(GO) run $(GOLANGCI_LINT_PACKAGE) run $(GOLANGCI_LINT_ARGS)
-	$(GO) run $(DEADCODE_PACKAGE) -generated=false -test code.gitea.io/gitea > .cur-deadcode-out
-	@$(DIFF) .deadcode-out .cur-deadcode-out; \
-	if [ $$? -eq 1 ]; then \
-		echo "Please run 'make lint-go-fix' and commit the result"; \
-		exit 1; \
-	fi
 
 .PHONY: lint-go-fix
 lint-go-fix:
 	$(GO) run $(GOLANGCI_LINT_PACKAGE) run $(GOLANGCI_LINT_ARGS) --fix
-	$(GO) run $(DEADCODE_PACKAGE) -generated=false -test code.gitea.io/gitea > .deadcode-out
 
 # workaround step for the lint-go-windows CI task because 'go run' can not
 # have distinct GOOS/GOARCH for its build and run steps
diff --git a/modules/util/legacy.go b/modules/util/legacy.go
index 2d4de01949..2ea293a2be 100644
--- a/modules/util/legacy.go
+++ b/modules/util/legacy.go
@@ -4,6 +4,10 @@
 package util
 
 import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"errors"
 	"io"
 	"os"
 )
@@ -36,3 +40,52 @@ func CopyFile(src, dest string) error {
 	}
 	return os.Chmod(dest, si.Mode())
 }
+
+// AESGCMEncrypt (from legacy package): encrypts plaintext with the given key using AES in GCM mode. should be replaced.
+func AESGCMEncrypt(key, plaintext []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := rand.Read(nonce); err != nil {
+		return nil, err
+	}
+
+	ciphertext := gcm.Seal(nil, nonce, plaintext, nil)
+	return append(nonce, ciphertext...), nil
+}
+
+// AESGCMDecrypt (from legacy package): decrypts ciphertext with the given key using AES in GCM mode. should be replaced.
+func AESGCMDecrypt(key, ciphertext []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+
+	size := gcm.NonceSize()
+	if len(ciphertext)-size <= 0 {
+		return nil, errors.New("ciphertext is empty")
+	}
+
+	nonce := ciphertext[:size]
+	ciphertext = ciphertext[size:]
+
+	plainText, err := gcm.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return plainText, nil
+}
diff --git a/modules/util/legacy_test.go b/modules/util/legacy_test.go
index b7991bd365..e732094c29 100644
--- a/modules/util/legacy_test.go
+++ b/modules/util/legacy_test.go
@@ -4,6 +4,8 @@
 package util
 
 import (
+	"crypto/aes"
+	"crypto/rand"
 	"fmt"
 	"os"
 	"testing"
@@ -35,3 +37,21 @@ func TestCopyFile(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, testContent, dstContent)
 }
+
+func TestAESGCM(t *testing.T) {
+	t.Parallel()
+
+	key := make([]byte, aes.BlockSize)
+	_, err := rand.Read(key)
+	assert.NoError(t, err)
+
+	plaintext := []byte("this will be encrypted")
+
+	ciphertext, err := AESGCMEncrypt(key, plaintext)
+	assert.NoError(t, err)
+
+	decrypted, err := AESGCMDecrypt(key, ciphertext)
+	assert.NoError(t, err)
+
+	assert.Equal(t, plaintext, decrypted)
+}