Java数字签名——RSA算法

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数字签名：带有密钥（公钥，私钥）的消息摘要算法。

验证数据的完整性，认证数据的来源，抗否性

OSI参考模型

私钥签名，公钥验证

签名算法：RSA，DSA，ECDSA

算法1 ：RSA

MD,SHA两类

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密钥长度均是 512～65536(64的整数倍)

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实现方：JDK 默认长度：1024

MD2withRSA

MD5withRSA

SHA1withRSA

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实现方：BC 默认长度：2048

SHA224withRSA

SHA256withRSA

SHA384withRSA

SHA512withRSA

RIPEMD128withRSA

RIPEMD160withRSA

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package RSA; import com.sun.org.apache.xerces.internal.impl.dv.util.HexBin; import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec; public class Rsa {
public static String src = "hello human";
public static void main(String[] args) {
jdkRSA();
}
public static void jdkRSA(){
try{
// 密钥初始化
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(512);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey = (RSAPublicKey)keyPair.getPublic() ;
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey)keyPair.getPrivate() ;
// 签名
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
Signature signature = Signature.getInstance("MD5withRSA");
signature.initSign(privateKey);
signature.update(src.getBytes());
byte []arr = signature.sign();
System.out.println("jdk rsa sign:"+ HexBin.encode(arr));
// 验证签名
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded()) ;
keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
signature = Signature.getInstance("MD5withRSA");
signature.initVerify(publicKey);
signature.update(src.getBytes());
boolean bool = signature.verify(arr);
System.out.println("jdk rsa verify:"+bool);
}catch (Exception e){ }
}
}