次の問題があります。コードには、単純な文字列を暗号化/復号化するための 2 つの関数があります。
それで：
文字列「someString」を関数に渡す必要があります。
public static String doEncryption(String input) {
try {
if (!RSAService.areKeysPresent()) {
RSAService.generateKey();
}
ObjectInputStream inputStream;
// Encrypt the string using the public key
inputStream = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));
PublicKey publicKey = (PublicKey) inputStream.readObject();
byte[] cipherText = RSAService.encrypt(input, publicKey);
return cipherText.toString();
} catch (Exception e) {
e.printStackTrace();
}
return "ERROR: Public key file is probably missing";
}
関数は「[B@61decc8c」doEncryption("someString")を返します
ここで、この文字列を URL に埋め込む必要があり、サーバー側のコードはそこから取得する必要があります。
これまでのところすべて良いですが、関数を呼び出すと
public static String doDecryption(String input) {
try {
if (!RSAService.areKeysPresent()) {
RSAService.generateKey();
}
ObjectInputStream inputStream;
// Decrypt the cipher text using the private key.
inputStream = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));
PrivateKey privateKey = (PrivateKey) inputStream.readObject();
String out = decrypt(input.getBytes(), privateKey);
return out;
} catch (Exception e) {
e.printStackTrace();
}
return "ERROR: Private key file is probably missing or doesn't match the public key";
}
次の例外を除いてdoDecryption("[B@61decc8c")悲鳴：
javax.crypto.BadPaddingException: Data must start with zero
at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:325)
at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:272)
at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:356)
at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:382)
at javax.crypto.Cipher.doFinal(Cipher.java:2087)
at rsaendecryptor.RSAService.decrypt(RSAService.java:132)
at rsaendecryptor.RSAService.doDecryption(RSAService.java:180)
at rsaendecryptor.RSAEnDecrypt.main(RSAEnDecrypt.java:20)
java.lang.NullPointerException
at java.lang.String.<init>(String.java:556)
at rsaendecryptor.RSAService.decrypt(RSAService.java:138)
at rsaendecryptor.RSAService.doDecryption(RSAService.java:180)
at rsaendecryptor.RSAEnDecrypt.main(RSAEnDecrypt.java:20)
これを回避する方法はありますか? クライアント側とサーバー側の間で文字列を渡す必要があるのは、それらが異なるドメインにある可能性があるためです。文字列が実際に .Net ロジックから生成され、Java サーバー側に送信されることは言うまでもありません。文字列への暗号化は正常に機能します...復号化を修正するにはどうすればよいですか。
完全なクラス コードは次のとおりです。
public class RSAService {
/**
* String to hold name of the encryption algorithm.
*/
public static final String ALGORITHM = "RSA";
/**
* String to hold the name of the private key file.
*/
public static final String PRIVATE_KEY_FILE = "private.key";
/**
* String to hold name of the public key file.
*/
public static final String PUBLIC_KEY_FILE = "public.key";
/**
* Generate key which contains a pair of private and public key using 1024
* bytes. Store the set of keys in Prvate.key and Public.key files.
*
*/
public static void generateKey() {
try {
final KeyPairGenerator keyGen = KeyPairGenerator.getInstance(ALGORITHM);
keyGen.initialize(1024);
final KeyPair key = keyGen.generateKeyPair();
File privateKeyFile = new File(PRIVATE_KEY_FILE);
File publicKeyFile = new File(PUBLIC_KEY_FILE);
// Create files to store public and private key
privateKeyFile.createNewFile();
if (publicKeyFile.getParentFile() != null) {
publicKeyFile.getParentFile().mkdirs();
}
publicKeyFile.createNewFile();
// Saving the Public key in a file
ObjectOutputStream publicKeyOS = new ObjectOutputStream(
new FileOutputStream(publicKeyFile));
publicKeyOS.writeObject(key.getPublic());
publicKeyOS.close();
// Saving the Private key in a file
ObjectOutputStream privateKeyOS = new ObjectOutputStream(
new FileOutputStream(privateKeyFile));
privateKeyOS.writeObject(key.getPrivate());
privateKeyOS.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* The method checks if the pair of public and private key has been
* generated.
*
* @return flag indicating if the pair of keys were generated.
*/
public static boolean areKeysPresent() {
File privateKey = new File(PRIVATE_KEY_FILE);
File publicKey = new File(PUBLIC_KEY_FILE);
if (privateKey.exists() && publicKey.exists()) {
return true;
}
return false;
}
/**
* Encrypt the plain text using public key.
*
* @param text : original plain text
* @param key :The public key
* @return Encrypted text
* @throws java.lang.Exception
*/
public static byte[] encrypt(String text, PublicKey key) {
byte[] cipherText = null;
try {
// get an RSA cipher object and print the provider
final Cipher cipher = Cipher.getInstance(ALGORITHM);
// encrypt the plain text using the public key
cipher.init(Cipher.ENCRYPT_MODE, key);
cipherText = cipher.doFinal(text.getBytes());
} catch (Exception e) {
e.printStackTrace();
}
return cipherText;
}
/**
* Decrypt text using private key.
*
* @param text :encrypted text
* @param key :The private key
* @return plain text
* @throws java.lang.Exception
*/
public static String decrypt(byte[] text, PrivateKey key) {
byte[] dectyptedText = null;
try {
// get an RSA cipher object and print the provider
final Cipher cipher = Cipher.getInstance(ALGORITHM);
// decrypt the text using the private key
cipher.init(Cipher.DECRYPT_MODE, key);
dectyptedText = cipher.doFinal(text);
} catch (Exception ex) {
ex.printStackTrace();
}
return new String(dectyptedText);
}
public static String doEncryption(String input) {
try {
if (!RSAService.areKeysPresent()) {
RSAService.generateKey();
}
ObjectInputStream inputStream;
// Encrypt the string using the public key
inputStream = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));
PublicKey publicKey = (PublicKey) inputStream.readObject();
byte[] cipherText = RSAService.encrypt(input, publicKey);
return cipherText.toString();
} catch (Exception e) {
e.printStackTrace();
}
return "ERROR: Public key file is probably missing";
}
public static String doDecryption(String input) {
try {
if (!RSAService.areKeysPresent()) {
RSAService.generateKey();
}
ObjectInputStream inputStream;
// Decrypt the cipher text using the private key.
inputStream = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));
PrivateKey privateKey = (PrivateKey) inputStream.readObject();
String out = decrypt(input.getBytes(), privateKey);
return out;
} catch (Exception e) {
e.printStackTrace();
}
return "ERROR: Private key file is probably missing or doesn't match the public key";
}
}