java中如何从pfx文件/pem文件中获取RSA公钥的指数和模值

Question

我想使用java从pfx文件中提取有关RSA公钥的信息。

我有一个pfx文件，并转换为x509 Pem文件。从pem文件，使用下面的命令在终端：

openssl x509 -in file.pem -text

我可以查看公钥指数和模值

主题公钥信息：

Public Key Algorithm: rsaEncryption
    Public-Key: (2048 bit)
    Modulus:
        00:da:7c:e0:3e:c4:62:8d:ce:29:04:2f:93:78:7c:
        :
         6a:e7:c9:7c:8b:6f:09:5c:75:5f:8c:5e:9c:6a:b9:
        7:32:90: a4:4b
    Exponent: 65537 (0x10001)

如何在java中提取上述信息？

输入：PFX文件和密码

输出：公钥指数和模值。

我使用下面的代码来提取公钥指数和模数，但我没有得到使用openssl提取的值。我怀疑java.security.cert.证书是否使用其他DER格式？？

什么是openssl的java等价物？

代码：

KeyStore ks = KeyStore.getInstance("pkcs12");
ks.load(new FileInputStream(file), password.toCharArray());
Enumeration enumeration = ks.aliases();
while (enumeration.hasMoreElements()) {
    String alias = (String) enumeration.nextElement();
    java.security.cert.Certificate certificate = ks.getCertificate(alias);
    PublicKey publickey = certificate.getPublicKey();
}

Answer 1

我添加这个答案是因为我最近尝试使用java从原始公钥字符串中获取模数和指数（另请参见https://crypto.stackexchange.com/questions/18031/how-to-find-modulus-from-a-rsa-public-key，并认为其他人可能会发现以下代码很有用：

String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCqGKukO1De7zhZj6+H0qtjTkVxwTCpvKe4eCZ0FPqri0cb2JZfXJ/DgYSF6vUpwmJG8wVQZKjeGcjDOL5UlsuusFncCzWBQ7RKNUSesmQRMSGkVb1/3j+skZ6UtW+5u09lHNsj6tQ51s1SPrCBkedbNf0Tp0GbMJDyR4e9T04ZZwIDAQAB";

try {
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        byte[] keyBytes = Base64.getDecoder().decode(publicKey.getBytes("UTF-8"));
        X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
        PublicKey fileGeneratedPublicKey = keyFactory.generatePublic(spec);
        RSAPublicKey rsaPub  = (RSAPublicKey)(fileGeneratedPublicKey);
        BigInteger publicKeyModulus = rsaPub.getModulus();
        BigInteger publicKeyExponent  = rsaPub.getPublicExponent();
        System.out.println("publicKeyModulus: " + publicKeyModulus);
        System.out.println("publicKeyExponent: " + publicKeyExponent);
    } catch (NoSuchAlgorithmException | UnsupportedEncodingException | InvalidKeySpecException e) {
        System.out.println(e.getMessage());
        e.printStackTrace();
    }

给出预期输出：

publicKeyModulus: 119445732379544598056145200053932732877863846799652384989588303737527328743970559883211146487286317168142202446955508902936035124709397221178664495721428029984726868375359168203283442617134197706515425366188396513684446494070223079865755643116690165578452542158755074958452695530623055205290232290667934914919
publicKeyExponent: 65537

Answer 2

Adding to the above Java Program to extract the n-modulus and e-exponent of the Base64 format of RSA would be as follows.

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

public class ModulusExpFromPublicKeyRSA {
    public static void main(String args[]) {
        String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCqGKukO1De7zhZj6+H0qtjTkVxwTCpvKe4eCZ0FPqri0cb2JZfXJ/DgYSF6vUpwmJG8wVQZKjeGcjDOL5UlsuusFncCzWBQ7RKNUSesmQRMSGkVb1/3j+skZ6UtW+5u09lHNsj6tQ51s1SPrCBkedbNf0Tp0GbMJDyR4e9T04ZZwIDAQAB";

        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] keyBytes = Base64.getDecoder().decode(publicKey.getBytes("UTF-8"));
            X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
            PublicKey fileGeneratedPublicKey = keyFactory.generatePublic(spec);
            RSAPublicKey rsaPub  = (RSAPublicKey)(fileGeneratedPublicKey);
            BigInteger publicKeyModulus = rsaPub.getModulus();
            BigInteger publicKeyExponent  = rsaPub.getPublicExponent();
            System.out.println("publicKeyModulus: " + publicKeyModulus);
            System.out.println("publicKeyExponent: " + publicKeyExponent);
            String nModulus=Base64.getUrlEncoder().encodeToString(publicKeyModulus.toByteArray());
            String eExponent=Base64.getUrlEncoder().encodeToString(publicKeyExponent.toByteArray());
            System.out.println("n Modulus for RSA Algorithm: " + nModulus);
            System.out.println("e Exponent for RSA Algorithm: " + eExponent);
        } catch (NoSuchAlgorithmException | UnsupportedEncodingException | InvalidKeySpecException e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }


    }

}


publicKeyModulus: 119445732379544598056145200053932732877863846799652384989588303737527328743970559883211146487286317168142202446955508902936035124709397221178664495721428029984726868375359168203283442617134197706515425366188396513684446494070223079865755643116690165578452542158755074958452695530623055205290232290667934914919
publicKeyExponent: 65537
n Modulus for RSA Algorithm: AKoYq6Q7UN7vOFmPr4fSq2NORXHBMKm8p7h4JnQU-quLRxvYll9cn8OBhIXq9SnCYkbzBVBkqN4ZyMM4vlSWy66wWdwLNYFDtEo1RJ6yZBExIaRVvX_eP6yRnpS1b7m7T2Uc2yPq1DnWzVI-sIGR51s1_ROnQZswkPJHh71PThln
e Exponent for RSA Algorithm: AQAB

Answer 3

您需要向下转换到透明的java.security.interfaces.RSAPublicKey类型。然后您可以访问模数和公共指数。

KeyStore ks = KeyStore.getInstance("pkcs12");
ks.load(new FileInputStream(file), password.toCharArray());
Enumeration<String> enumeration = ks.aliases();
while (enumeration.hasMoreElements()) {
  String alias = enumeration.nextElement();
  Certificate certificate = ks.getCertificate(alias);
  RSAPublicKey pub = (RSAPublicKey) certificate.getPublicKey();
  System.out.println(pub.getModulus().toString(16));
  System.out.println(pub.getPublicExponent().toString(16));
}