diff --git a/README.md b/README.md
index 416413d..1447087 100644
--- a/README.md
+++ b/README.md
@@ -53,5 +53,6 @@ def test_sm2():
 
 ### 参考
 [1] https://github.com/guanzhi/GmSSL  
-[2] https://github.com/gongxian-ding/gmssl-python  
-[3] https://github.com/pyca/cryptography
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+[2] https://github.com/duanhongyi/gmssl  
+[3] https://github.com/gongxian-ding/gmssl-python  
+[4] https://github.com/pyca/cryptography
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