diff --git a/main.go b/main.go
index 18fa40f..eeeb865 100644
--- a/main.go
+++ b/main.go
@@ -5,6 +5,7 @@ import (
 	"log"
 	"math/rand"
 	"os"
+	"strings"
 	"time"
 
 	"s.mcquay.me/dm/psyfer/psyfer"
@@ -109,7 +110,15 @@ func main() {
 		Short: "vignenere cipher",
 		Long:  `perform vigenere cipher`,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Println("missing input, see -h (--help) for more info")
+			if len(args) < 1 || key == "" {
+				fmt.Println("missing input, see -h (--help) for more info")
+				os.Exit(1)
+			}
+			for _, arg := range args {
+				arg = strings.ToUpper(strings.Replace(arg, " ", "", -1))
+				key = strings.ToUpper(strings.Replace(key, " ", "", -1))
+				fmt.Printf("%v\n", psyfer.VigenereCipher(arg, key, decrypt))
+			}
 		},
 	}
 
@@ -165,15 +174,6 @@ func main() {
 		},
 	}
 
-	var crack = &cobra.Command{
-		Use:   "times [# times] [string to echo]",
-		Short: "Echo anything to the screen more times",
-		Long:  `echo things multiple times back to the user by providing a count and a string.`,
-		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Println("crack")
-		},
-	}
-
 	//transpose flags
 	split.Flags().BoolVarP(
 		&decrypt,
@@ -219,10 +219,24 @@ func main() {
 		false,
 		"decrypt",
 	)
+	//virenere flags
+	vig.Flags().StringVarP(
+		&key,
+		"key",
+		"k",
+		"",
+		"encryption key string",
+	)
+	vig.Flags().BoolVarP(
+		&decrypt,
+		"decrypt",
+		"d",
+		false,
+		"decrypt",
+	)
 
 	var rootCmd = &cobra.Command{Use: "app"}
 	rootCmd.AddCommand(sub, aes, trans, vig)
 	trans.AddCommand(random, railfence, split)
-	vig.AddCommand(crack)
 	rootCmd.Execute()
 }
diff --git a/psyfer/vigenere.go b/psyfer/vigenere.go
new file mode 100644
index 0000000..f0344f8
--- /dev/null
+++ b/psyfer/vigenere.go
@@ -0,0 +1,29 @@
+package psyfer
+
+func VigenereCipher(input string, key string, decrypt bool) string {
+	alphabet := "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	chars := []rune(input)
+	k := []rune(key)
+	keyPos := 0
+	output := ""
+	for _, m := range chars {
+		index := int(m - 'A')
+		offset := int(k[keyPos]-'A') % 26
+		if decrypt {
+			index -= offset
+		} else {
+			index += offset
+		}
+		if index >= 26 {
+			index -= 26
+		} else if index < 0 {
+			index += 26
+		}
+		output += string(alphabet[index])
+		keyPos++
+		if keyPos == len(key) {
+			keyPos = 0
+		}
+	}
+	return output
+}
diff --git a/psyfer/vigenere_test.go b/psyfer/vigenere_test.go
new file mode 100644
index 0000000..a03487a
--- /dev/null
+++ b/psyfer/vigenere_test.go
@@ -0,0 +1,35 @@
+package psyfer
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestVigenereCipher(t *testing.T) {
+	key := "vig"
+	input := "theboyhasthebag"
+	input = strings.ToUpper(strings.Replace(input, " ", "", -1))
+	key = strings.ToUpper(strings.Replace(key, " ", "", -1))
+	expected := "OPKWWECIYOPKWIM"
+	actual := VigenereCipher(input, key, false)
+	if expected != actual {
+		t.Errorf(
+			"failed VigenereCipher:\n\texpected: % q\n\t  actual: % q",
+			expected,
+			actual,
+		)
+	}
+	key = "vig"
+	input = "OPKWWECIYOPKWIM"
+	input = strings.ToUpper(strings.Replace(input, " ", "", -1))
+	key = strings.ToUpper(strings.Replace(key, " ", "", -1))
+	expected = "THEBOYHASTHEBAG"
+	actual = VigenereCipher(input, key, true)
+	if expected != actual {
+		t.Errorf(
+			"failed VigenereCipher:\n\texpected: % q\n\t  actual: % q",
+			expected,
+			actual,
+		)
+	}
+}