在此讨论之后,这是一个简单的教程,如何在不使用任何第三方库的情况下使用 java 中的 ECDSA 算法对字符串进行签名。但问题是:
- 如何将公钥和私钥转换为字符串?(因为我想将它们发送到数据库中)。
- 有人可以帮我创建一个简单的教程,介绍如何在java中使用ECDSA算法验证消息吗? 此时,我需要包含签名和公钥作为验证方法。
这是我在java代码中的场景,假设有一个发送端和接收端:
- 发送方端
package sender;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
public class Sign {
public static void main(String[] args) throws Exception {
/*
* Generate a key pair
*/
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("EC");
SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
keyGen.initialize(256, random);
KeyPair pair = keyGen.generateKeyPair();
/*
Generate the private and the public key
*/
PrivateKey priv = pair.getPrivate();
/*
*and then Convert the priv key into a String;
*HOW can i do that ? this what i'm asking
*/
PublicKey pub = pair.getPublic();
/*
Convert the pub key into a String;
HOW can i do that ? this what i'm asking
*/
/*
-------Encrypt the pub and the priv key, i do with my own code
-------Store the enrypted pub & priv key into the database
-------I'm doing this with my own code
*/
/*
* Create a Signature object and initialize it with the private key
*/
Signature dsa = Signature.getInstance("SHA1withECDSA");
dsa.initSign(priv);
String str = "This is string to sign";
byte[] strByte = str.getBytes("UTF-8");
dsa.update(strByte);
/*
* Now that all the data to be signed has been read in, generate a
* signature for it
*/
byte[] realSig = dsa.sign();
System.out.println("Signature: " +
new BigInteger(1, realSig).toString(16));
/*
and Then i'm storing this signature into my database.
i have done with this
*/
}
}
- 接收方
package recipient;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
public class Verify {
public static void main(String[] args) throws Exception {
/*
Step one, taking public key from the database.
Step two, receive the message + signature.
Step three, split the message and signature into an "array[0]" for message,
and "array[1] for the signature"
Verify the signature <--- Here's what im asking to anybody,
how can i do, i mean the sample code ?
*/
}
}
对不起,我的英语:D不好
你问了很多关于处理ECDSA的不同问题。我将在这里解决您关于数据库存储的第一个问题。如果您想了解如何正确使用它,我建议您对 ECDSA 的机制进行一些额外的研究。无论如何,这里给出的例子很难断章取义。
要将密钥存储为字符串,必须首先检索表示其编码格式的密钥的字节数组(注意:编码未加密)。这可以通过使用类 Key
中的 getEncoded()
方法来完成,该方法是公钥和私钥的超级接口。
例:
PrivateKey key = // ...
byte[] enc_key = key.getEncoded();
// Byte array to string
StringBuilder key_builder = new StringBuilder();
for(byte b : enc_key){
key_builder.append(String.format("%02x", b));
}
String serialized_key = key_builder.toString();
若要从数据库再次加载密钥,请将字符串分析为字节数组,将其传递到相应的密钥规范中,然后使用密钥工厂检索它。
例:
String serialzed_key = // ...
byte[] encoded_key = // serialzed_key -> byte array conversion
// If key is private, use PKCS #8
PKCS8EncodedKeySpec formatted_private = new PKCS8EncodedKeySpec(encoded_key);
// or, if key is public, use X.509
X509EncodedKeySpec formatted_public = new X509EncodedKeySpec(encoded_key);
// Retrieve key using KeyFactory
KeyFactory kf = KeyFactory.getInstance("EC");
PublicKey pub = kf.generatePublic(formatted_public);
PrivateKey priv = kf.generatePrivate(formatted_private);
如果您只想使用 ECDSA 作为签名算法,则验证与使用 verify
方法而不是sign
方法进行签名相同,如下所示:
byte[] message_hash = // ...
byte[] candidate_message = // ...
PublicKey pub = // ...
Signature dsa = Signature.getInstance("SHA1withECDSA");
dsa.initVerify(pub);
dsa.update(candidate_message);
boolean success = dsa.verify(message_hash);