private static void digitalSign(String text)throws Exception{
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024);
KeyPair keyPair = kpg.generateKeyPair();
byte[] data = text.getBytes("UTF8");
Signature sig = Signature.getInstance("MD5WithRSA");
sig.initSign(keyPair.getPrivate());
sig.update(data);
byte[] signatureBytes=sig.sign();
System.out.println("Signature:\n"+Base64.encode(signatureBytes));
sig.initVerify(keyPair.getPublic());
sig.update(data);
boolean verified = false;
try{
verified = sig.verify(signatureBytes);
}catch(SignatureException se){
se.printStackTrace();
verified = false;
}
if(verified){
System.out.println("Signature verified.");
}else{
System.out.println("Signature did not match.");
}
}
public static void main(String[] args){
try{
String text="abc";
digitalSign(text);
}catch(Exception e){
e.printStackTrace();
}
}
}
四、运用证书解决公钥，私钥传输的问题
1.生成自签名 CA 根证书
openssl genrsa -des3 -out ca.key 1024
openssl rsa -in server.key -out ca.key
