从文件加载RSA公钥 [英] Load RSA public key from file
问题描述
我已经生成了一个私钥:
I've generated a private key with:
openssl genrsa [-out file] –des3
在此之后我生成了一个公钥:
After this I've generated a public key with:
openssl rsa –pubout -in private.key [-out file]
我想用我的私钥签署一些邮件,并使用我的公钥验证其他一些邮件,使用如下代码:
I want to sign some messages with my private key, and verify some other messages with my public key, using code like this:
public String sign(String message) throws SignatureException{
try {
Signature sign = Signature.getInstance("SHA1withRSA");
sign.initSign(privateKey);
sign.update(message.getBytes("UTF-8"));
return new String(Base64.encodeBase64(sign.sign()),"UTF-8");
} catch (Exception ex) {
throw new SignatureException(ex);
}
}
public boolean verify(String message, String signature) throws SignatureException{
try {
Signature sign = Signature.getInstance("SHA1withRSA");
sign.initVerify(publicKey);
sign.update(message.getBytes("UTF-8"));
return sign.verify(Base64.decodeBase64(signature.getBytes("UTF-8")));
} catch (Exception ex) {
throw new SignatureException(ex);
}
}
我找到了将私钥转换为PKCS8的解决方案格式并加载它。它适用于以下代码:
I found a solution to convert my private key to PKCS8 format and load it. It works with some code like this:
public PrivateKey getPrivateKey(String filename) throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory kf =
KeyFactory.getInstance("RSA");
return kf.generatePrivate(spec);
}
最后我的问题是:如何加载我的RSA Public来自文件的密钥?
我想我可能需要将公钥文件转换为x509格式,并使用 X509EncodedKeySpec
。但是我怎么能这样做?
I think maybe I need to convert my public key file to x509 format, and use X509EncodedKeySpec
. But how can I do this?
推荐答案
生成2048位RSA私钥
Generate a 2048-bit RSA private key
$ openssl genrsa -out private_key.pem 2048
将私钥转换为PKCS#8格式(所以Java可以读取它)
Convert private Key to PKCS#8 format (so Java can read it)
$ openssl pkcs8 -topk8 -inform PEM -outform DER -in private_key.pem -out private_key.der -nocrypt
以DER格式输出公钥部分(因此Java可以读取它)
Output public key portion in DER format (so Java can read it)
$ openssl rsa -in private_key.pem -poutout -outform DER -out public_key.der
私钥
Private key
import java.io.*;
import java.nio.*;
import java.security.*;
import java.security.spec.*;
public class PrivateKeyReader {
public static PrivateKey get(String filename)
throws Exception {
byte[] keyBytes = Files.readAllBytes(Paths.get(filename));
PKCS8EncodedKeySpec spec =
new PKCS8EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePrivate(spec);
}
}
公钥
Public key
import java.io.*;
import java.nio.*;
import java.security.*;
import java.security.spec.*;
public class PublicKeyReader {
public static PublicKey get(String filename)
throws Exception {
byte[] keyBytes = Files.readAllBytes(Paths.get(filename));
X509EncodedKeySpec spec =
new X509EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePublic(spec);
}
}
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