go get github.com/gorilla/securecookie 

package main
import (
	"github.com/beego/beego"
)
func main() {
	beego.Router("/", &MainController{})
	beego.RunWithMiddleWares(":8080")
}
type MainController struct {
	beego.Controller
}
func (this *MainController) Get() {
	this.Ctx.Output.Cookie("userid", "1234567")
	this.Ctx.Output.Body([]byte("Hello World"))
}

package main
import (
	"github.com/beego/beego"
	"github.com/gorilla/securecookie"
)
func main() {
	beego.Router("/", &MainController{})
	beego.RunWithMiddleWares(":8080")
}
type MainController struct {
	beego.Controller
}
func (this *MainController) Get() {
	// Hash keys should be at least 32 bytes long
	var hashKey = []byte("keep-it-secret-keep-it-safe-----")
	// 實例化securecookie
	var s = securecookie.New(hashKey, nil)
	name := "userid"
	value := "1234567"
    // 對value進(jìn)行編碼
	encodeValue, _ := s.Encode(name, value)
    // 輸出編碼后的cookie值
	this.Ctx.Output.Cookie(name, encodeValue)
	this.Ctx.Output.Body([]byte("Hello World"))
}

package main
import (
	"fmt"
	"github.com/beego/beego"
	"github.com/gorilla/securecookie"
)
func main() {
	beego.Router("/", &MainController{})
	beego.RunWithMiddleWares(":8080")
}
type MainController struct {
	beego.Controller
}
func (this *MainController) Get() {
	// Hash keys should be at least 32 bytes long
	var hashKey = []byte("keep-it-secret-keep-it-safe-----")
	// Block keys should be 16 bytes (AES-128) or 32 bytes (AES-256) long.
	// Shorter keys may weaken the encryption used.
	var blockKey = []byte("1234567890123456")
	// 實例化securecookie
	var s = securecookie.New(hashKey, blockKey)
	value := map[string]string{
		"id": "1234567",
	}
	name := "userid"
	//value := "1234567"
	//
	encodeValue, err := s.Encode(name, value)
	fmt.Println("encodeValue:", encodeValue, err)
    // 解析到decodeValue中
	decodeValue := make(map[string]string)
	s.Decode(name, encodeValue, &decodeValue)
	fmt.Println("decodeValue:", decodeValue)
	this.Ctx.Output.Cookie(name, encodeValue)
	this.Ctx.Output.Body([]byte("Hello World"))
}

	// Hash keys should be at least 32 bytes long
	var hashKey = []byte("keep-it-secret-keep-it-safe-----")
	// Block keys should be 16 bytes (AES-128) or 32 bytes (AES-256) long.
	// Shorter keys may weaken the encryption used.
	var blockKey = []byte("1234567890123456")
	// 實例化securecookie
	var s = securecookie.New(hashKey, blockKey)
	name := "userid"
	value := "1234567"
	encodeValue, err := s.Encode(name, value)

package main
import (
	"fmt"
	"github.com/beego/beego"
	"github.com/gorilla/securecookie"
)
func main() {
	beego.Router("/", &MainController{})
	beego.RunWithMiddleWares(":8080")
}
type MainController struct {
	beego.Controller
}
func (this *MainController) Get() {
	// Hash keys should be at least 32 bytes long
	var hashKey = []byte("keep-it-secret-keep-it-safe-----")
	// Block keys should be 16 bytes (AES-128) or 32 bytes (AES-256) long.
	// Shorter keys may weaken the encryption used.
	var blockKey = []byte("1234567890123456")
	// 實例化securecookie
	var s = securecookie.New(hashKey, blockKey)
	encodeValue := this.Ctx.GetCookie("userid")
	value := ""
	s.Decode("userid", encodeValue, &value)
	fmt.Println("decode value is :", value, encodeValue)
	this.Ctx.Output.Cookie("userid", value)
	this.Ctx.Output.Body([]byte("Hello World"))
}

func (s *SecureCookie) Encode(name string, value interface{}) (string, error)

func (e GobEncoder) Serialize(src interface{}) ([]byte, error) {
	buf := new(bytes.Buffer)
	enc := gob.NewEncoder(buf)
	if err := enc.Encode(src); err != nil {
		return nil, cookieError{cause: err, typ: usageError}
	}
	return buf.Bytes(), nil
}

cookie := securecookie.New([]byte("keep-it-secret-keep-it-safe-----")
cookie.SetSerializer(securecookie.JSONEncoder{})

	// 2. Encrypt (optional).
	if s.block != nil {
		if b, err = encrypt(s.block, b); err != nil {
			return "", cookieError{cause: err, typ: usageError}
		}
	}

func encrypt(block cipher.Block, value []byte) ([]byte, error) {
	iv := GenerateRandomKey(block.BlockSize())
	if iv == nil {
		return nil, errGeneratingIV
	}
	// Encrypt it.
	stream := cipher.NewCTR(block, iv)
	stream.XORKeyStream(value, value)
	// Return iv + ciphertext.
	return append(iv, value...), nil
}

	// 3. Create MAC for "name|date|value". Extra pipe to be used later.
	b = []byte(fmt.Sprintf("%s|%d|%s|", name, s.timestamp(), b))
	mac := createMac(hmac.New(s.hashFunc, s.hashKey), b[:len(b)-1])
	// Append mac, remove name.
	b = append(b, mac...)[len(name)+1:]
	// 4. Encode to base64.
	b = encode(b)

// SetSecureCookie puts value into cookie after encoded the value.
func (c *Controller) SetSecureCookie(Secret, name, value string, others ...interface{}) {
	c.Ctx.SetSecureCookie(Secret, name, value, others...)
}
// SetSecureCookie Set Secure cookie for response.
func (ctx *Context) SetSecureCookie(Secret, name, value string, others ...interface{}) {
	vs := base64.URLEncoding.EncodeToString([]byte(value))
	timestamp := strconv.FormatInt(time.Now().UnixNano(), 10)
	h := hmac.New(sha256.New, []byte(Secret))
	fmt.Fprintf(h, "%s%s", vs, timestamp)
	sig := fmt.Sprintf("%02x", h.Sum(nil))
	cookie := strings.Join([]string{vs, timestamp, sig}, "|")
	ctx.Output.Cookie(name, cookie, others...)
}