TKSS-536: Update READMEs for ECKeyPairGenerator

kona-crypto/README.md

@@ -39,12 +39,24 @@ the less the position is, the higher the priority is. The minimum value is 1.
 ### SM2
 
 #### Key pair
-Generating SM2 key pair is the same as generating the key pairs on other EC curves. It just needs to invoke the standard JDK APIs.
+Generating SM2 key pair is the same as generating the key pairs on other EC curves. It just needs to invoke the standard JDK APIs. `KonaCrypto` provides two `KeyPairGenerator` implementations for generating SM2 key pair:
 
-Create KeyPairGenerator instance.
+- The JDK builtin `ECKeyPairGenerator`. In the key pair generated by this implementations, the format of private key is `PKCS#8` and the format of public key is `X.509`.
+- A new introduced `SM2KeyPairGenerator`. In the key pair generated by this implementations, the format of the both keys is `RAW`. The length of private key is 32-bytes. The length of public key is 65-bytes, The format is `04||x||y`. `04` represents the uncompressed format; `x` and `y` are the coordinates of the public point in the curve, and both are 32-bytes.
+
+Create `KeyPairGenerator` implementation on `ECKeyPairGenerator`.
+
+```
+KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC);
+keyPairGenerator.initialize(spec);
+```
+
+`spec` can be `SM2ParameterSpec` (use `SM2ParameterSpec.instance()` to create the instance) or `ECGenParameterSpec` (use `new ECGenParameterSpec("curveSM2")` to create the instance).
+
+If create `KeyPairGenerator` implementation on `SM2KeyPairGenerator`, the codes are the belows,
 
 ```
-KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("SM2");
+KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("SM2);
 ```
 
 Generate key pair.
@@ -57,7 +69,7 @@ ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
 
 SM2 key pair is also EC key pair, so the public key and private key are also ECPublicKey and ECPrivateKey respectively.
 
-SM2 public key is 65-bytes length. The format is `04|x|y`. `04` represents the uncompressed format; `x` and `y` are the coordinates of the public point in the curve.
+SM2 public key is 65-bytes length.
 
 ```
 byte[] encodedPublicKey = publicKey.getEncoded();

kona-crypto/README_cn.md

@@ -39,34 +39,32 @@ position的值越小，代表的优先级越高，最小可为1。
 ### SM2
 
 #### 密钥对
-生成SM2密钥对与生成JDK自带的其它算法（如EC）密钥对的方式是完全相同的，仅需要调用标准的JDK API就可以生成密钥对。
+生成SM2密钥对与生成JDK自带的其它算法（如EC）密钥对的方式是完全相同的，仅需要调用标准的JDK API就可以了。`KonaCrypto`提供了两个`KeyPairGenerator`实现去生成SM2密钥对：
 
-创建KeyPairGenerator实例。
+- JDK自带的`ECKeyPairGenerator`。它生成的密钥对中，私钥格式为`PKCS#8`，公钥格式为`X.509`。
+- 新引入的`SM2KeyPairGenerator`。它生成的密钥对中，私钥和公钥格式均为`RAW`。私钥长度为32字节。公钥为长度为65字节，格式为`04||x||y`，其中`04`表示非压缩格式，`x`和`y`分别为该公钥点在椭圆曲线上的仿射横坐标和纵坐标的值。
 
-```
-KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("SM2");
-```
-
-生成密钥对。
+创建使用`ECKeyPairGenerator`的`KeyPairGenerator`实例。
 
 ```
-KeyPair keyPair = keyPairGenerator.generateKeyPair();
-ECPublicKey publicKey = (ECPublicKey) keyPair.getPublic();
-ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
+KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC);
+keyPairGenerator.initialize(spec);
 ```
 
-SM2的密钥对本质还是EC密钥对，所以其中的公钥与私钥也分别符合ECPublicKey与ECPrivateKey的属性。
+其中，`spec`可以为`SM2ParameterSpec`（使用`SM2ParameterSpec.instance()`创建它的实例）或者是`ECGenParameterSpec`（使用`new ECGenParameterSpec("curveSM2")`创建它的实例）。
 
-SM2公钥的编码长度固定为65字节，其格式为`04|x|y`，其中`04`表示非压缩格式，`x`和`y`分别为该公钥点在椭圆曲线上的仿射横坐标和纵坐标的值。
+若创建使用`SM2KeyPairGenerator`的`KeyPairGenerator`实例，则代码如下。
 
 ```
-byte[] encodedPublicKey = publicKey.getEncoded();
+KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("SM2);
 ```
 
-SM2私钥的编码长度固定为32字节，无编码格式。
+生成密钥对。
 
 ```
-byte[] encodedPrivateKey = privateKey.getEncoded();
+KeyPair keyPair = keyPairGenerator.generateKeyPair();
+ECPublicKey publicKey = (ECPublicKey) keyPair.getPublic();
+ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
 ```
 
 关于密钥对生成器API的更详细用法，请参考[KeyPairGenerator]的官方文档。