From ee35aa68ba25d794103fe8dc5dd394bef6be8b88 Mon Sep 17 00:00:00 2001
From: Sun Yimin <emmansun@users.noreply.github.com>
Date: Tue, 12 Sep 2023 08:44:56 +0800
Subject: [PATCH] smx509: add example test case for reference #155

---
 smx509/example_test.go | 113 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)

diff --git a/smx509/example_test.go b/smx509/example_test.go
index 0f5e958..3b8d29c 100644
--- a/smx509/example_test.go
+++ b/smx509/example_test.go
@@ -5,8 +5,10 @@ import (
 	"crypto/ecdsa"
 	"crypto/ed25519"
 	"crypto/rsa"
+	"encoding/asn1"
 	"encoding/pem"
 	"fmt"
+	"strings"
 
 	"github.com/emmansun/gmsm/sm2"
 	"github.com/emmansun/gmsm/smx509"
@@ -47,3 +49,114 @@ B6kLUsqHlVyglXgoMEwo8Sr8xb/Q3gDMNnd7Wyp2bJE9ksb60ansO4QaKg==
 	// pub is of type ECDSA: sm2p256v1
 	// true
 }
+
+func ExampleParsePKCS8PrivateKey() {
+	const privPEM = `
+-----BEGIN PRIVATE KEY-----
+MIGHAgEAMBMGByqGSM49AgEGCCqBHM9VAYItBG0wawIBAQQgW+2/sIbWJ5bqzQ4D
+Vh8sQ2B/6I1PLGIcItXgGxAcdA6hRANCAAQ/Sx9dzxrMJwgoHmQ76X6g4EoM/2ca
+Cm0E4OyvrAVYYipqoI2JhFccq9ZYC5cA9cMj9JW0l5fBtSHp3dSd6wNH
+-----END PRIVATE KEY-----`
+	block, _ := pem.Decode([]byte(privPEM))
+	if block == nil {
+		panic("failed to parse PEM block containing the private key")
+	}
+	key, err := smx509.ParsePKCS8PrivateKey(block.Bytes)
+	if err != nil {
+		panic("failed to parse DER encoded private key: " + err.Error())
+	}
+	switch priv := key.(type) {
+	case *sm2.PrivateKey:
+		fmt.Println("priv is of type SM2:", priv.Params().Name)
+	default:
+		panic("unexpected type of private key")
+	}
+	// Output:
+	// priv is of type SM2: sm2p256v1
+}
+
+func ExampleParseTypedECPrivateKey() {
+	// Of course, you can remove EC PARAMETERS to make it simple.
+	// https://security.stackexchange.com/questions/29778/why-does-openssl-writes-ec-parameters-when-generating-private-key
+	const privPEM = `	
+-----BEGIN EC PARAMETERS-----
+BggqgRzPVQGCLQ==
+-----END EC PARAMETERS-----
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIFvtv7CG1ieW6s0OA1YfLENgf+iNTyxiHCLV4BsQHHQOoAoGCCqBHM9V
+AYItoUQDQgAEP0sfXc8azCcIKB5kO+l+oOBKDP9nGgptBODsr6wFWGIqaqCNiYRX
+HKvWWAuXAPXDI/SVtJeXwbUh6d3UnesDRw==
+-----END EC PRIVATE KEY-----`
+	var keyDERBlock *pem.Block
+	keyPEMBlock := []byte(privPEM)
+	for {
+		keyDERBlock, keyPEMBlock = pem.Decode(keyPEMBlock)
+		if keyDERBlock == nil {
+			break
+		}
+		if keyDERBlock.Type == "EC PARAMETERS" {
+			var oid asn1.ObjectIdentifier
+			_, err := asn1.Unmarshal(keyDERBlock.Bytes, &oid)
+			if err != nil {
+				panic("failed to parse private key ecparams")
+			}
+			fmt.Printf("%v\n", oid)
+		}
+		if keyDERBlock.Type == "EC PRIVATE KEY" || strings.HasSuffix(keyDERBlock.Type, " PRIVATE KEY") {
+			break
+		}
+	}
+	if keyDERBlock == nil {
+		panic("failed to parse PEM block containing the private key")
+	}
+
+	key, err := smx509.ParseTypedECPrivateKey(keyDERBlock.Bytes)
+	if err != nil {
+		panic("failed to parse DER encoded private key: " + err.Error())
+	}
+	switch priv := key.(type) {
+	case *sm2.PrivateKey:
+		fmt.Println("priv is of type SM2:", priv.Params().Name)
+	default:
+		panic("unexpected type of private key")
+	}
+	// Output:
+	// 1.2.156.10197.1.301
+	// priv is of type SM2: sm2p256v1
+}
+
+func ExampleParseSM2PrivateKey() {
+	// Of course, you can remove EC PARAMETERS to make it simple.
+	// https://security.stackexchange.com/questions/29778/why-does-openssl-writes-ec-parameters-when-generating-private-key
+	const privPEM = `	
+-----BEGIN EC PARAMETERS-----
+BggqgRzPVQGCLQ==
+-----END EC PARAMETERS-----
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIFvtv7CG1ieW6s0OA1YfLENgf+iNTyxiHCLV4BsQHHQOoAoGCCqBHM9V
+AYItoUQDQgAEP0sfXc8azCcIKB5kO+l+oOBKDP9nGgptBODsr6wFWGIqaqCNiYRX
+HKvWWAuXAPXDI/SVtJeXwbUh6d3UnesDRw==
+-----END EC PRIVATE KEY-----`
+	var keyDERBlock *pem.Block
+	keyPEMBlock := []byte(privPEM)
+	for {
+		keyDERBlock, keyPEMBlock = pem.Decode(keyPEMBlock)
+		if keyDERBlock == nil {
+			break
+		}
+		if keyDERBlock.Type == "EC PRIVATE KEY" || strings.HasSuffix(keyDERBlock.Type, " PRIVATE KEY") {
+			break
+		}
+	}
+	if keyDERBlock == nil {
+		panic("failed to parse PEM block containing the private key")
+	}
+
+	key, err := smx509.ParseSM2PrivateKey(keyDERBlock.Bytes)
+	if err != nil {
+		panic("failed to parse DER encoded private key: " + err.Error())
+	}
+	fmt.Println("priv is of type SM2:", key.Params().Name)
+	// Output:
+	// priv is of type SM2: sm2p256v1	
+}