diff --git a/session/session.go b/session/session.go
index 88e94d59..3cbd2b05 100644
--- a/session/session.go
+++ b/session/session.go
@@ -28,19 +28,13 @@
 package session
 
 import (
-	"crypto/hmac"
-	"crypto/md5"
 	"crypto/rand"
-	"crypto/sha1"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"net/url"
 	"time"
-
-	"github.com/astaxie/beego/utils"
 )
 
 // SessionStore contains all data for one session process with specific id.
@@ -81,16 +75,15 @@ func Register(name string, provide Provider) {
 }
 
 type managerConfig struct {
-	CookieName        string `json:"cookieName"`
-	EnableSetCookie   bool   `json:"enableSetCookie,omitempty"`
-	Gclifetime        int64  `json:"gclifetime"`
-	Maxlifetime       int64  `json:"maxLifetime"`
-	Secure            bool   `json:"secure"`
-	SessionIDHashFunc string `json:"sessionIDHashFunc"`
-	SessionIDHashKey  string `json:"sessionIDHashKey"`
-	CookieLifeTime    int    `json:"cookieLifeTime"`
-	ProviderConfig    string `json:"providerConfig"`
-	Domain            string `json:"domain"`
+	CookieName      string `json:"cookieName"`
+	EnableSetCookie bool   `json:"enableSetCookie,omitempty"`
+	Gclifetime      int64  `json:"gclifetime"`
+	Maxlifetime     int64  `json:"maxLifetime"`
+	Secure          bool   `json:"secure"`
+	CookieLifeTime  int    `json:"cookieLifeTime"`
+	ProviderConfig  string `json:"providerConfig"`
+	Domain          string `json:"domain"`
+	SessionIdLength int64  `json:"sessionIdLength"`
 }
 
 // Manager contains Provider and its configuration.
@@ -129,11 +122,9 @@ func NewManager(provideName, config string) (*Manager, error) {
 	if err != nil {
 		return nil, err
 	}
-	if cf.SessionIDHashFunc == "" {
-		cf.SessionIDHashFunc = "sha1"
-	}
-	if cf.SessionIDHashKey == "" {
-		cf.SessionIDHashKey = string(generateRandomKey(16))
+
+	if cf.SessionIdLength == 0 {
+		cf.SessionIdLength = 16
 	}
 
 	return &Manager{
@@ -144,11 +135,14 @@ func NewManager(provideName, config string) (*Manager, error) {
 
 // Start session. generate or read the session id from http request.
 // if session id exists, return SessionStore with this id.
-func (manager *Manager) SessionStart(w http.ResponseWriter, r *http.Request) (session SessionStore) {
-	cookie, err := r.Cookie(manager.config.CookieName)
-	if err != nil || cookie.Value == "" {
-		sid := manager.sessionId(r)
-		session, _ = manager.provider.SessionRead(sid)
+func (manager *Manager) SessionStart(w http.ResponseWriter, r *http.Request) (session SessionStore, err error) {
+	cookie, errs := r.Cookie(manager.config.CookieName)
+	if errs != nil || cookie.Value == "" {
+		sid, errs := manager.sessionId(r)
+		if errs != nil {
+			return nil, errs
+		}
+		session, err = manager.provider.SessionRead(sid)
 		cookie = &http.Cookie{Name: manager.config.CookieName,
 			Value:    url.QueryEscape(sid),
 			Path:     "/",
@@ -163,12 +157,18 @@ func (manager *Manager) SessionStart(w http.ResponseWriter, r *http.Request) (se
 		}
 		r.AddCookie(cookie)
 	} else {
-		sid, _ := url.QueryUnescape(cookie.Value)
+		sid, errs := url.QueryUnescape(cookie.Value)
+		if errs != nil {
+			return nil, errs
+		}
 		if manager.provider.SessionExist(sid) {
-			session, _ = manager.provider.SessionRead(sid)
+			session, err = manager.provider.SessionRead(sid)
 		} else {
-			sid = manager.sessionId(r)
-			session, _ = manager.provider.SessionRead(sid)
+			sid, err = manager.sessionId(r)
+			if err != nil {
+				return nil, err
+			}
+			session, err = manager.provider.SessionRead(sid)
 			cookie = &http.Cookie{Name: manager.config.CookieName,
 				Value:    url.QueryEscape(sid),
 				Path:     "/",
@@ -219,7 +219,10 @@ func (manager *Manager) GC() {
 
 // Regenerate a session id for this SessionStore who's id is saving in http request.
 func (manager *Manager) SessionRegenerateId(w http.ResponseWriter, r *http.Request) (session SessionStore) {
-	sid := manager.sessionId(r)
+	sid, err := manager.sessionId(r)
+	if err != nil {
+		return
+	}
 	cookie, err := r.Cookie(manager.config.CookieName)
 	if err != nil && cookie.Value == "" {
 		//delete old cookie
@@ -251,36 +254,16 @@ func (manager *Manager) GetActiveSession() int {
 	return manager.provider.SessionAll()
 }
 
-// Set hash function for generating session id.
-func (manager *Manager) SetHashFunc(hasfunc, hashkey string) {
-	manager.config.SessionIDHashFunc = hasfunc
-	manager.config.SessionIDHashKey = hashkey
-}
-
 // Set cookie with https.
 func (manager *Manager) SetSecure(secure bool) {
 	manager.config.Secure = secure
 }
 
-// generate session id with rand string, unix nano time, remote addr by hash function.
-func (manager *Manager) sessionId(r *http.Request) (sid string) {
-	bs := make([]byte, 32)
-	if n, err := io.ReadFull(rand.Reader, bs); n != 32 || err != nil {
-		bs = utils.RandomCreateBytes(32)
+func (manager *Manager) sessionId(r *http.Request) (string, error) {
+	b := make([]byte, manager.config.SessionIdLength)
+	n, err := rand.Read(b)
+	if n != len(b) || err != nil {
+		return "", fmt.Errorf("Could not successfully read from the system CSPRNG.")
 	}
-	sig := fmt.Sprintf("%s%d%s", r.RemoteAddr, time.Now().UnixNano(), bs)
-	if manager.config.SessionIDHashFunc == "md5" {
-		h := md5.New()
-		h.Write([]byte(sig))
-		sid = hex.EncodeToString(h.Sum(nil))
-	} else if manager.config.SessionIDHashFunc == "sha1" {
-		h := hmac.New(sha1.New, []byte(manager.config.SessionIDHashKey))
-		fmt.Fprintf(h, "%s", sig)
-		sid = hex.EncodeToString(h.Sum(nil))
-	} else {
-		h := hmac.New(sha1.New, []byte(manager.config.SessionIDHashKey))
-		fmt.Fprintf(h, "%s", sig)
-		sid = hex.EncodeToString(h.Sum(nil))
-	}
-	return
+	return hex.EncodeToString(b), nil
 }