如何从java中的pfx文件/pem文件获取RSA公钥的指数和模数值
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How to get exponent and modulus value of RSA public key from pfx file/pem file in java
提问by Ajitha Robert
I want to extract information about RSA Public Key from the pfx file using java.
我想使用 java 从 pfx 文件中提取有关 RSA 公钥的信息。
I have a pfx file and converted to x509 Pem file. From pem file, Using the below command in terminal:
我有一个 pfx 文件并转换为 x509 Pem 文件。从 pem 文件，在终端中使用以下命令：
openssl x509 -in file.pem -text
I am able to view the public key exponent and modulus value
我可以查看公钥指数和模数值
Subject Public Key Info:
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)
How to extract the above information in java?
java中如何提取上述信息？
Input:pfxfile and password
输入：pfxfile 和密码
Output:public key exponent and modulus value.
输出：公钥指数和模数值。
I m using the below code to extract the public key exponent and modulus, but i am not getting the value that is extracted using openssl. I doubt whether java.security.cert.Certificate uses some other DER format??
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.Certificate 是否使用其他 DER 格式？？
What is the java equivalent of openssl?
什么是openssl的java等价物？
Code:
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();
}
采纳答案by erickson
You need to downcast to the transparent java.security.interfaces.RSAPublicKeytype. Then you can access the modulus and public exponents.
您需要向下转换为透明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));
}
回答by user728785
I'm adding this answer as I recently tried to get the modulus and exponent from a raw public key string using java (also see https://crypto.stackexchange.com/questions/18031/how-to-find-modulus-from-a-rsa-public-key, from which the following public key was obtained) and thought that others may find the following code helpful:
我正在添加这个答案，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（另请参阅https://crypto.stackexchange.com/questions/18031/how-to-find-modulus-from -a-rsa-public-key，从中获得以下公钥）并认为其他人可能会发现以下代码有用：
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();
}
Giving the expected output:
给出预期的输出：
publicKeyModulus: 119445732379544598056145200053932732877863846799652384989588303737527328743970559883211146487286317168142202446955508902936035124709397221178664495721428029984726868375359168203283442617134197706515425366188396513684446494070223079865755643116690165578452542158755074958452695530623055205290232290667934914919
publicKeyExponent: 65537
