add:电子签集成版回调解密demo

examples/ess/v20201111/ess_callback.go

@@ -0,0 +1,50 @@
+package v20201111
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"encoding/base64"
+	"fmt"
+	"testing"
+)
+
+func AesDecrypt(crypted, key []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	blockSize := block.BlockSize()
+	blockMode := cipher.NewCBCDecrypter(block, key[:blockSize])
+	origData := make([]byte, len(crypted))
+	blockMode.CryptBlocks(origData, crypted)
+	origData = PKCS7UnPadding(origData)
+	return origData, nil
+}
+
+// PKCS7UnPadding 去除填充
+func PKCS7UnPadding(origData []byte) []byte {
+	length := len(origData)
+	unPadding := int(origData[length-1])
+	return origData[:(length - unPadding)]
+}
+
+func TestDecrypt(t *testing.T) {
+	// 传入CallbackUrlKey
+	key := "***********"
+	// 传入密文
+	content := "***********"
+
+	// base64解密
+	crypted, err := base64.StdEncoding.DecodeString(content)
+	if err != nil {
+		fmt.Printf("base64 DecodeString returned: %s", err)
+		return
+	}
+
+	origData, err := AesDecrypt(crypted, []byte(key))
+	if err != nil {
+		fmt.Printf("AesDecrypt returned: %s", err)
+		return
+	}
+	fmt.Printf("%s", string(origData))
+}