ZanderZhang · December 13, 2019 03:24 · Apr 14, 2014 · Apr 14, 2014
diff --git a/des.go b/des.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"crypto/des"
 	"errors"
-	"testing"
 )
 
 func PKCS5Padding(ciphertext []byte, blockSize int) []byte {
@@ -73,23 +72,3 @@ func DesDecrypt(src, key []byte) ([]byte, error) {
 	// out = PKCS5UnPadding(out)
 	return out, nil
 }
-
-
-func TestDesEncrypt(t *testing.T) {
-	key := []byte("5e8487e6")
-	origtext := []byte("hello world123563332")
-
-	erytext, err := DesEncrypt(origtext, key)
-	if err != nil {
-		t.Fatal(err)
-	}
-	fmt.Printf("%v\n", erytext)
-	destext, err2 := DesDecrypt(erytext, key)
-	if err2 != nil {
-		t.Fatal(err2)
-	}
-	fmt.Println(string(destext))
-	fmt.Println(len(origtext), len(string(destext)))
-	fmt.Println(string(origtext) == string(destext))
-}
-
diff --git a/des_test.go b/des_test.go
@@ -0,0 +1,24 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestDesEncrypt(t *testing.T) {
+	key := []byte("5e8487e6")
+	origtext := []byte("hello world123563332")
+
+	erytext, err := DesEncrypt(origtext, key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fmt.Printf("%v\n", erytext)
+	destext, err2 := DesDecrypt(erytext, key)
+	if err2 != nil {
+		t.Fatal(err2)
+	}
+	fmt.Println(string(destext))
+	fmt.Println(len(origtext), len(string(destext)))
+	fmt.Println(string(origtext) == string(destext))
+}
diff --git a/test.sh b/test.sh
@@ -0,0 +1 @@
+go test . -v
diff --git a/des.go b/des.go
@@ -0,0 +1,95 @@
+package main
+
+import (
+	"bytes"
+	"crypto/des"
+	"errors"
+	"testing"
+)
+
+func PKCS5Padding(ciphertext []byte, blockSize int) []byte {
+	padding := blockSize - len(ciphertext)%blockSize
+	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
+	return append(ciphertext, padtext...)
+}
+
+func PKCS5UnPadding(origData []byte) []byte {
+	length := len(origData)
+	unpadding := int(origData[length-1])
+	return origData[:(length - unpadding)]
+}
+
+func ZeroPadding(ciphertext []byte, blockSize int) []byte {
+	padding := blockSize - len(ciphertext)%blockSize
+	padtext := bytes.Repeat([]byte{0}, padding)
+	return append(ciphertext, padtext...)
+}
+
+func ZeroUnPadding(origData []byte) []byte {
+	return bytes.TrimFunc(origData,
+		func(r rune) bool {
+			return r == rune(0)
+		})
+}
+
+func DesEncrypt(src, key []byte) ([]byte, error) {
+	block, err := des.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	bs := block.BlockSize()
+	src = ZeroPadding(src, bs)
+	// src = PKCS5Padding(src, bs)
+	if len(src)%bs != 0 {
+		return nil, errors.New("Need a multiple of the blocksize")
+	}
+	out := make([]byte, len(src))
+	dst := out
+	for len(src) > 0 {
+		block.Encrypt(dst, src[:bs])
+		src = src[bs:]
+		dst = dst[bs:]
+	}
+	return out, nil
+}
+
+func DesDecrypt(src, key []byte) ([]byte, error) {
+	block, err := des.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]byte, len(src))
+	dst := out
+	bs := block.BlockSize()
+	if len(src)%bs != 0 {
+		return nil, errors.New("crypto/cipher: input not full blocks")
+	}
+	for len(src) > 0 {
+		block.Decrypt(dst, src[:bs])
+		src = src[bs:]
+		dst = dst[bs:]
+	}
+	out = ZeroUnPadding(out)
+	// out = PKCS5UnPadding(out)
+	return out, nil
+}
+
+
+func TestDesEncrypt(t *testing.T) {
+	key := []byte("5e8487e6")
+	origtext := []byte("hello world123563332")
+
+	erytext, err := DesEncrypt(origtext, key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fmt.Printf("%v\n", erytext)
+	destext, err2 := DesDecrypt(erytext, key)
+	if err2 != nil {
+		t.Fatal(err2)
+	}
+	fmt.Println(string(destext))
+	fmt.Println(len(origtext), len(string(destext)))
+	fmt.Println(string(origtext) == string(destext))
+}
+