decrypt func added

main.go

@@ -7,6 +7,8 @@ import (
   "crypto/rand"
   "fmt"
   "io"
+  "io/ioutil"
+  "os"
 )
 
 func checkErr(err error) {
@@ -33,14 +35,28 @@ func encrypt(data []byte, key []byte) []byte {
   return sealed
 }
 
-func main() {
-  var passwd string = "ThisAPassphrase"
-  fmt.Println(passwd)
-  key := keyMkr(passwd)
-  fmt.Println(key)
-  data := []byte("Thi is some data")
-  dataSealed := encrypt(data,key)
-  fmt.Println(string(data))
-  fmt.Println(string(dataSealed))
+func decrypt(sealed []byte, key []byte) []byte {
+  block, err := aes.NewCipher(key)
+  checkErr(err)
+  gcm, err := cipher.NewGCM(block)
+  nonceSize := gcm.NonceSize()
+  nonce, ctxt := sealed[:nonceSize], sealed[nonceSize:]
+  data, err := gcm.Open(nil, nonce, ctxt, nil)
+  checkErr(err)
+  return data
+}
+
+func main() {
+  var passwd string = "ThisAnnPassphrase"
+  fmt.Println(passwd)
+  key := keyMkr(passwd)
+  fmt.Println(string(key))
+  data := []byte("Thi is some data")
+  fmt.Println(string(data))
+  fmt.Println("encryption:")
+  dataSealed := encrypt(data,key)
+  fmt.Println(string(dataSealed))
+  fmt.Println("decryption:")
+  fmt.Println(string(decrypt(dataSealed,key)))
 }