关于密钥管理：如何从我们创建的密钥库中检索公钥和私钥

How to retrieve my public and private key from the keystore we created

我的任务如下：

从我创建的密钥库中检索我的公钥和私钥。
使用这些密钥使用我的RSA 2048位公钥加密段落。
使用dsa-sha-1签名算法对结果进行数字签名。
将数字签名输出保存在名为output.dat的文件中。

下面的程序引发错误："java.security.invalidkeyException:没有安装的提供程序支持此密钥：sun.security.provider.dsapublickeyimpl"。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101

import java.security.*;
import java.security.KeyStore.*;
import java.io.*;
import java.security.PublicKey;
import java.security.PrivateKey;
import javax.crypto.Cipher;
import java.nio.charset.*;
import sun.security.provider.*;
import javax.crypto.*;

public class Code {

/**
* @param args the command line arguments
*/
public static void main(String[] args) {

try {

/* getting data for keystore */

File file = new File(System.getProperty("user.home") + File.separatorChar +".keystore");
FileInputStream is = new FileInputStream(file);
KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());

/*Information for certificate to be generated */
String password ="abcde";
String alias ="mykeys";
String alias1 ="skeys";

String filepath ="C:\\email.txt";

/* getting the key*/
keystore.load(is, password.toCharArray());
PrivateKey key = (PrivateKey)keystore.getKey(alias,"bemylife".toCharArray());
//PrivateKey key = cert1.getPrivateKey();
//PublicKey key1= (PrivateKey)key;

/* Get certificate of public key */
java.security.cert.Certificate cert = keystore.getCertificate(alias);

/* Here it prints the public key*/
System.out.println("Public Key:");
System.out.println(cert.getPublicKey());

/* Here it prints the private key*/
System.out.println("
Private Key:");
System.out.println(key);

Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE,cert.getPublicKey());

String cleartextFile ="C:\\email.txt";
String ciphertextFile ="D:\\ciphertextRSA.png";

FileInputStream fis = new FileInputStream(cleartextFile);
FileOutputStream fos = new FileOutputStream(ciphertextFile);
CipherOutputStream cos = new CipherOutputStream(fos, cipher);

byte[] block = new byte[32];
int i;
while ((i = fis.read(block)) != -1) {
cos.write(block, 0, i);
}
cos.close();

/* computing the signature*/
Signature dsa = Signature.getInstance("SHA1withDSA","SUN");
dsa.initSign(key);
FileInputStream f = new FileInputStream(ciphertextFile);
BufferedInputStream in = new BufferedInputStream(f);
byte[] buffer = new byte[1024];
int len;
while ((len = in.read(buffer)) >= 0) {
dsa.update(buffer, 0, len);
};
in.close();

/* Here it prints the signature*/
System.out.println("Digital Signature :");
System.out.println( dsa.sign());

/* Now Exporting Certificate */
System.out.println("Exporting Certificate.");
byte[] buffer_out = cert.getEncoded();
FileOutputStream os = new FileOutputStream(new File("d:\\signedcetificate.cer"));
os.write(buffer_out);
os.close();

/* writing signature to output.dat file */
byte[] buffer_out1 = dsa.sign();
FileOutputStream os1 = new FileOutputStream(new File("d:\\output.dat"));
os1.write(buffer_out1);
os1.close();

} catch (Exception e) {System.out.println(e);}

}
}

相关讨论

您必须将它从keystore文件(可能以.jks结尾)读取到java.security.keystore对象中。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

/**
* Reads a Java keystore from a file.
*
* @param keystoreFile
* keystore file to read
* @param password
* password for the keystore file
* @param keyStoreType
* type of keystore, e.g., JKS or PKCS12
* @return the keystore object
* @throws KeyStoreException
* if the type of KeyStore could not be created
* @throws IOException
* if the keystore could not be loaded
* @throws NoSuchAlgorithmException
* if the algorithm used to check the integrity of the keystore
* cannot be found
* @throws CertificateException
* if any of the certificates in the keystore could not be loaded
*/
public static KeyStore loadKeyStore(final File keystoreFile,
final String password, final String keyStoreType)
throws KeyStoreException, IOException, NoSuchAlgorithmException,
CertificateException {
if (null == keystoreFile) {
throw new IllegalArgumentException("Keystore url may not be null");
}
LOG.debug("Initializing key store: {}", keystoreFile.getAbsolutePath());
final URI keystoreUri = keystoreFile.toURI();
final URL keystoreUrl = keystoreUri.toURL();
final KeyStore keystore = KeyStore.getInstance(keyStoreType);
InputStream is = null;
try {
is = keystoreUrl.openStream();
keystore.load(is, null == password ? null : password.toCharArray());
LOG.debug("Loaded key store");
} finally {
if (null != is) {
is.close();
}
}
return keystore;
}

一旦你拥有了KeyStore，你就可以使用Certificate和公钥和私钥。

但使用它来签署文本并将其保存到文件中更为复杂，而且很容易出错。使用给定的公钥查看符号字符串，并将getKeyPair方法替换为使用KeyStore的方法。有点像

1
2
3
4
5
6
7
8
9

public static KeyPair getKeyPair(final KeyStore keystore,
final String alias, final String password) {
final Key key = (PrivateKey) keystore.getKey(alias, password.toCharArray());

final Certificate cert = keystore.getCertificate(alias);
final PublicKey publicKey = cert.getPublicKey();

return KeyPair(publicKey, (PrivateKey) key);
}

(显然有点粗糙，我手边没有样本)