From 4db3046001e67c43e358d87912c0e96d1758a46b Mon Sep 17 00:00:00 2001
From: Sun Yimin <emmansun@users.noreply.github.com>
Date: Tue, 11 Jun 2024 11:01:05 +0800
Subject: [PATCH] pkcs7: support older CFCA integration #225

---
 pkcs/cipher_sm4.go    | 10 ++++++++++
 pkcs7/encrypt_test.go |  1 +
 2 files changed, 11 insertions(+)

diff --git a/pkcs/cipher_sm4.go b/pkcs/cipher_sm4.go
index 159d90e..6eb3aa5 100644
--- a/pkcs/cipher_sm4.go
+++ b/pkcs/cipher_sm4.go
@@ -53,3 +53,13 @@ var SM4GCM = &gcmBlockCipher{
 	},
 	nonceSize: 12,
 }
+
+// SM4 is the 128-bit key SM4 cipher in CBC mode, it's just for CFCA.
+var SM4 = &cbcBlockCipher{
+	baseBlockCipher: baseBlockCipher{
+		keySize:  16,
+		newBlock: sm4.NewCipher,
+		oid:      oidSM4,
+	},
+	ivSize: sm4.BlockSize,
+}
diff --git a/pkcs7/encrypt_test.go b/pkcs7/encrypt_test.go
index b288f3c..c316bd8 100644
--- a/pkcs7/encrypt_test.go
+++ b/pkcs7/encrypt_test.go
@@ -93,6 +93,7 @@ func TestEncryptSM(t *testing.T) {
 
 func TestEncryptCFCA(t *testing.T) {
 	ciphers := []pkcs.Cipher{
+		pkcs.SM4,
 		pkcs.SM4CBC,
 		pkcs.SM4GCM,
 	}