我的任务如下：
output.dat的文件中。以下程序抛出错误：“java.security.InvalidKeyException：没有安装的提供程序支持此密钥：sun.security.provider.DSAPublicKeyImpl”。
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("\nPrivate 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);}
}
}
答案 0 :(得分：5)
您必须从密钥库文件（可能以.jks结尾）将其读取到java.security.KeyStore对象中。
/**
* 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;
}
获得KeyStore后，您可以访问Certificate以及公钥和私钥。
但是使用它来签署文本并将其保存在文件中更为复杂，并且容易出错。请查看Sign string using given Public Key并将getKeyPair方法替换为使用KeyStore的方法。
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，我没有方便的样品）
答案 1 :(得分：2)
问题是DSA密钥不适合RSA加密。您需要一个RSA密钥进行加密，也许您可以将签名算法切换到RSA / SHA1以避免需要两个密钥。
答案 2 :(得分：0)
我没有将Java代码存储在我的脑子顶部，但是一些通用的健全性检查是：
是您想要存储在哪里的公共证书？特别是，我的回忆是带有公钥和私钥的证书一起存储在一个别名下，所以你在那里设置的两个别名似乎很奇怪。尝试将两者存储在同一别名下，并在私钥和公钥调用中引用它。
您可以从证书中获取任何其他内容 - 例如，主题DN或颁发者DN都是证书中必须具有的字段。这样可以很好地证明证书正在按预期读取。
几乎在任何加密事务中，都要非常小心如何从文件中读取并传输编码方法。如果您已创建文件IO并以奇怪的方式从中提取，则可能会破坏密钥材料的编码。这是最后要检查的东西 - 通常Java和JKS对此并没有那么糟糕，但它确实发生了。同样，要明确文件的格式 - 例如，JKS文件与PKCS 12文件不同。
答案 3 :(得分：0)
trusted.load(in, ((PBCApplication) context.getApplicationContext()).getBuildSettings().getCertificatePass());
Enumeration enumeration = trusted.aliases();
while (enumeration.hasMoreElements()) {
String alias = (String) enumeration.nextElement();
System.out.println("alias name: " + alias);
Certificate certificate = trusted.getCertificate(alias);
certificate.getPublicKey();
}