Android中的RSA加密解密
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【中文标题】Android中的RSA加密解密【英文标题】:RSA Encryption Decryption in Android 【发布时间】:2012-09-10 10:06:43 【问题描述】:我正在 android 中实现 RSA 加密和解密的演示。我可以很好地执行加密,但在解密时我得到一个异常:>>java.security.InvalidKeyException: unknown key type passed to RSA
。
KeyPairGenerator kpg;
KeyPair kp;
PublicKey publicKey;
PrivateKey privateKey;
byte [] encryptedBytes,decryptedBytes;
Cipher cipher,cipher1;
String encrypted,decrypted;
public String RSAEncrypt (final String plain) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException
kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024);
kp = kpg.genKeyPair();
publicKey = kp.getPublic();
privateKey = kp.getPrivate();
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
encryptedBytes = cipher.doFinal(plain.getBytes());
encrypted = new String(encryptedBytes);
System.out.println("EEncrypted?????"+encrypted);
return encrypted;
public String RSADecrypt (final String result) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException
cipher1=Cipher.getInstance("RSA");
cipher1.init(Cipher.DECRYPT_MODE, privateKey);
decryptedBytes = cipher1.doFinal(result.getBytes());
decrypted = new String(decryptedBytes);
System.out.println("DDecrypted?????"+decrypted);
return decrypted;
我从这里调用函数:
encrypt.setOnClickListener(new OnClickListener()
public void onClick(View arg0)
try
RSAEncrypt rsaencrypt=new RSAEncrypt();
rsaencrypt.RSAEncrypt(name);
result=rsaencrypt.RSAEncrypt(name);
Toast.makeText(getBaseContext(), result.toString(),Toast.LENGTH_SHORT).show();
System.out.println("Result:"+result);
catch(Exception e)
e.printStackTrace();
Toast.makeText(getBaseContext(), e.toString(),Toast.LENGTH_LONG).show();
);
decrypt.setOnClickListener(new OnClickListener()
public void onClick(View arg0)
try
RSAEncrypt rsadecrypt=new RSAEncrypt();
rsadecrypt.RSADecrypt(result);
ans=rsadecrypt.RSADecrypt(result);
System.out.println("Result is"+ans);
Toast.makeText(getBaseContext(), ans.toString(),Toast.LENGTH_LONG).show();
catch(Exception e)
e.printStackTrace();
Toast.makeText(getBaseContext(), e.toString(),Toast.LENGTH_LONG).show();
System.out.println("Exception is>>"+e);
);
【问题讨论】:
【参考方案1】:在 RSA 中,您应该使用公钥进行加密,使用私钥进行解密。
您的示例代码用于加密和解密公钥 - 这是行不通的。
因此在解密部分你应该这样初始化密码:
cipher1.init(Cipher.DECRYPT_MODE, privateKey);
此外,您的代码还有第二个重大错误:
您正在将具有二进制内容的字节数组转换为字符串。
永远不要将二进制数据转换为字符串!
字符串用于字符串字符,而不是二进制数据。如果您想将二进制数据打包成字符串,例如使用 Hex 或 Base64 将其编码为可打印字符。
以下示例使用来自 org.apache.common.codec 包的十六进制编码器 - 必须安装第三方库。
public byte[] RSAEncrypt(final String plain) throws NoSuchAlgorithmException, NoSuchPaddingException,
InvalidKeyException, IllegalBlockSizeException, BadPaddingException
kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(2048);
kp = kpg.genKeyPair();
publicKey = kp.getPublic();
privateKey = kp.getPrivate();
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
encryptedBytes = cipher.doFinal(plain.getBytes());
System.out.println("EEncrypted?????" + new String(org.apache.commons.codec.binary.Hex.encodeHex(encryptedBytes)));
return encryptedBytes;
public String RSADecrypt(final byte[] encryptedBytes) throws NoSuchAlgorithmException, NoSuchPaddingException,
InvalidKeyException, IllegalBlockSizeException, BadPaddingException
cipher1 = Cipher.getInstance("RSA");
cipher1.init(Cipher.DECRYPT_MODE, privateKey);
decryptedBytes = cipher1.doFinal(encryptedBytes);
decrypted = new String(decryptedBytes);
System.out.println("DDecrypted?????" + decrypted);
return decrypted;
【讨论】:
非常感谢..你是对的..我做错了..但现在我得到了异常>> System.err(416): java.security.InvalidKeyException: unknown key type传递给 RSA 请帮助我..在此先感谢.. 谢谢。只说一句话:键是对称的。因此,您可以使用公共编码然后使用私有解码(确保您将加密数据发送给谁),或者使用私有编码,然后使用公共解码(以确保谁向您发送了加密数据)。执行 2(使用 2 个不同的密钥集),允许您强制执行“从谁”和“对谁”安全方面。 “使用私有编码”的情况称为签名。但是您永远不应该直接签署数据 - 始终只签署数据,否则您可能会遇到一些攻击(请参阅 IT 安全文献)。 总是只签什么? “总是只签名哈希”(SHA-256 或 SHA-1 或 ...)【参考方案2】:以下是 Android 的示例:
生成私有/公共 RSA 密钥对 加密字符串 解密加密字符串这些方法处理所有 base 64 编码/解码。
public void TestEncryptData(String dataToEncrypt)
// generate a new public/private key pair to test with (note. you should only do this once and keep them!)
KeyPair kp = getKeyPair();
PublicKey publicKey = kp.getPublic();
byte[] publicKeyBytes = publicKey.getEncoded();
String publicKeyBytesBase64 = new String(Base64.encode(publicKeyBytes, Base64.DEFAULT));
PrivateKey privateKey = kp.getPrivate();
byte[] privateKeyBytes = privateKey.getEncoded();
String privateKeyBytesBase64 = new String(Base64.encode(privateKeyBytes, Base64.DEFAULT));
// test encryption
String encrypted = encryptRSAToString(dataToEncrypt, publicKeyBytesBase64);
// test decryption
String decrypted = decryptRSAToString(encrypted, privateKeyBytesBase64);
public static KeyPair getKeyPair()
KeyPair kp = null;
try
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(2048);
kp = kpg.generateKeyPair();
catch (Exception e)
e.printStackTrace();
return kp;
public static String encryptRSAToString(String clearText, String publicKey)
String encryptedBase64 = "";
try
KeyFactory keyFac = KeyFactory.getInstance("RSA");
KeySpec keySpec = new X509EncodedKeySpec(Base64.decode(publicKey.trim().getBytes(), Base64.DEFAULT));
Key key = keyFac.generatePublic(keySpec);
// get an RSA cipher object and print the provider
final Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWITHSHA-256ANDMGF1PADDING");
// encrypt the plain text using the public key
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] encryptedBytes = cipher.doFinal(clearText.getBytes("UTF-8"));
encryptedBase64 = new String(Base64.encode(encryptedBytes, Base64.DEFAULT));
catch (Exception e)
e.printStackTrace();
return encryptedBase64.replaceAll("(\\r|\\n)", "");
public static String decryptRSAToString(String encryptedBase64, String privateKey)
String decryptedString = "";
try
KeyFactory keyFac = KeyFactory.getInstance("RSA");
KeySpec keySpec = new PKCS8EncodedKeySpec(Base64.decode(privateKey.trim().getBytes(), Base64.DEFAULT));
Key key = keyFac.generatePrivate(keySpec);
// get an RSA cipher object and print the provider
final Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWITHSHA-256ANDMGF1PADDING");
// encrypt the plain text using the public key
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] encryptedBytes = Base64.decode(encryptedBase64, Base64.DEFAULT);
byte[] decryptedBytes = cipher.doFinal(encryptedBytes);
decryptedString = new String(decryptedBytes);
catch (Exception e)
e.printStackTrace();
return decryptedString;
【讨论】:
【参考方案3】:我的班级:
package com.infovale.cripto;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.util.Arrays;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
public class RSA
KeyPairGenerator kpg;
KeyPair kp;
PublicKey publicKey;
PrivateKey privateKey;
byte[] encryptedBytes, decryptedBytes;
Cipher cipher, cipher1;
String encrypted, decrypted;
public String Encrypt (String plain) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException
kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024);
kp = kpg.genKeyPair();
publicKey = kp.getPublic();
privateKey = kp.getPrivate();
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
encryptedBytes = cipher.doFinal(plain.getBytes());
encrypted = bytesToString(encryptedBytes);
return encrypted;
public String Decrypt (String result) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException
cipher1=Cipher.getInstance("RSA");
cipher1.init(Cipher.DECRYPT_MODE, privateKey);
decryptedBytes = cipher1.doFinal(stringToBytes(result));
decrypted = new String(decryptedBytes);
return decrypted;
public String bytesToString(byte[] b)
byte[] b2 = new byte[b.length + 1];
b2[0] = 1;
System.arraycopy(b, 0, b2, 1, b.length);
return new BigInteger(b2).toString(36);
public byte[] stringToBytes(String s)
byte[] b2 = new BigInteger(s, 36).toByteArray();
return Arrays.copyOfRange(b2, 1, b2.length);
【讨论】:
【参考方案4】:使用RSAEcvypt方法时,填写PublicKey和private key。 当您解密生成的字节 [] 时,您的 publicKey 和 privateKey 为 NULL。 因此,您会收到此错误。
您应该使用静态密钥;
enter code here
KeyPairGenerator kpg;
KeyPair kp;
static PublicKey publicKey;
static PrivateKey privateKey;
byte [] encryptedBytes,decryptedBytes;
Cipher cipher,cipher1;
String encrypted,decrypted;
【讨论】:
这些是类属性,因为访问这些键的方法不是静态的,因此属性不必是静态的。事实上,当您可能需要创建具有不同数据值的多个类实例时,拥有静态属性是一个非常糟糕的选择。【参考方案5】:我认为问题在于您应该使用相同的密钥对来加密和解密密码。参考JavaDoc:
genKeyPair() This will generate a new key pair every time it is called.
【讨论】:
@jaredzhang..我编辑了我的代码..但我得到了同样的异常..请查看我编辑的代码.. @jaredzhang..我认为你是对的..但问题是现在我得到 java.lang.NullPointerException.. 您的新代码似乎不清楚,请确保您用于解密的私钥与您之前生成的相同。 @jaredzhang..嗨..我再次编辑了我的代码..所以..你看起来很清楚..请帮助我..非常感谢..也看看我的问题..我得到的例外现在也不同.... @jaredzhang 所以这不能用于将数据从一个应用程序发送到另一个应用程序,因为接收器应用程序将调用 genKeyPair() 并创建不同的密钥。有什么解决办法吗?以上是关于Android中的RSA加密解密的主要内容,如果未能解决你的问题,请参考以下文章