基于私钥的Android系统RSA解密

Question

java.security.spec.InvalidKeySpecException: java.lang.RuntimeException: error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag

public class AppUtils {


public static String encryptString(String value, Context context){
    byte[] encodedBytes = null;
    try {
        //Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidOpenSSL");
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.ENCRYPT_MODE,  getPublicKey(context) );
        encodedBytes = cipher.doFinal(value.getBytes());
    } catch (Exception e) {
        e.printStackTrace();
    }

    return Base64.encodeToString(encodedBytes, Base64.DEFAULT);
}

public static String decryptString(String value, Context context){
    byte[] decodedBytes = null;
    try {
        //Cipher c = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidOpenSSL");
        Cipher c = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        c.init(Cipher.DECRYPT_MODE,  getPrivateKey(context) );
        decodedBytes = c.doFinal(Base64.decode(value, Base64.DEFAULT));
    } catch (Exception e) {
        e.printStackTrace();
    }

    return new String(decodedBytes);
}


public static PrivateKey getPrivateKey(Context context){

    // reads the key_public key stored in a file
    InputStream is = context.getResources().openRawResource(R.raw.key_private);
    BufferedReader br = new BufferedReader(new InputStreamReader(is));
    List<String> lines = new ArrayList<String>();
    String line = null;

    try {


        while ((line = br.readLine()) != null)
            lines.add(line);


        // removes the first and last lines of the file (comments)
        if (lines.size() > 1 && lines.get(0).startsWith("-----") && lines.get(lines.size()-1).startsWith("-----")) {
           lines.remove(0);
         lines.remove(lines.size()-1);
        }

        // concats the remaining lines to a single String
        StringBuilder sb = new StringBuilder();
        for (String aLine: lines)
            sb.append(aLine);
        String keyString = sb.toString();

        byte [] encoded = Base64.decode(keyString, Base64.DEFAULT);

        KeyFactory keyFactory = KeyFactory.getInstance("RSA");

        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);

        PrivateKey myPrivKey = keyFactory.generatePrivate(keySpec);

        return myPrivKey;

    }catch (Exception e){

        e.printStackTrace();
    }
    return null;
}

public static PublicKey getPublicKey(Context context){

    // reads the key_public key stored in a file
    InputStream is = context.getResources().openRawResource(R.raw.key_public);
    BufferedReader br = new BufferedReader(new InputStreamReader(is));
    List<String> lines = new ArrayList<String>();
    String line = null;


    try {


        while ((line = br.readLine()) != null)
            lines.add(line);

        // removes the first and last lines of the file (comments)
        if (lines.size() > 1 && lines.get(0).startsWith("-----") && lines.get(lines.size()-1).startsWith("-----")) {
            lines.remove(0);
            lines.remove(lines.size()-1);
        }

        // concats the remaining lines to a single String
        StringBuilder sb = new StringBuilder();
        for (String aLine: lines)
            sb.append(aLine);
        String keyString = sb.toString();

        // converts the String to a PublicKey instance
        byte[] keyBytes = Base64.decode(keyString, Base64.DEFAULT);
        X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey key = keyFactory.generatePublic(spec);

        return key;
    }catch (Exception e){
            e.printStackTrace();
    }

    return null;
}
}

String encryptedString =  AppUtils.encryptString("SHANKAR", MainActivity.this);

Log.d("DX1", " Encrypted String " + encryptedString );


String decryptedString =  AppUtils.decryptString(encryptedString, MainActivity.this);

Log.d("DX1", " decrypted String " + decryptedString );

PrivateKey myPrivKey = keyFactory.generatePrivate(keySpec);

-----BEGIN PUBLIC KEY-----
MIGeMA0GCSqGSIb3DQEBAQUAA4GMADCBiAKBgEac6cgM4Ch5vY2Rqvzw2ARaNEHv
PCbXWW1nPy3ft8CNFyLoIltwrnouY0azYECclONARh48qQUQ+UG62wNUtciLq9yX
3m0ePE7u/RYmNUnGWok6LMNZK1gGBu6TBnzNjDWi3CuR00xFzZ2TBtUMDowOa/+b
tfGTywGDLPJjgbtPAgMBAAE=
-----END PUBLIC KEY-----

我的私钥：

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

Answer 1

我也有同样的问题，试了几天想知道它是如何工作的，最后，我得到了它！

您的私钥不是PKCS#8格式。

PKCS8键以

转换应用程序中的私钥。为此，您需要将第三方库包含到项目中。

将这一行添加到您的应用程序梯度中

编译'com.madgag.spongycastle:core:1.56.0.0'

public static PrivateKey getPrivateKey(Context context) throws 
    GeneralSecurityException, IOException {
            InputStream is = context.getResources().openRawResource(R.raw.rsa_2048_priv);
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            List<String> lines = new ArrayList<String>();
            String line = null;

                while ((line = br.readLine()) != null)
                    lines.add(line);

                if (lines.size() > 1 && lines.get(0).startsWith("-----") && lines.get(lines.size() - 1).startsWith("-----")) {
                    lines.remove(0);
                    lines.remove(lines.size() - 1);
                }

                StringBuilder sb = new StringBuilder();
                for (String aLine : lines)
                    sb.append(aLine);
                String keyString = sb.toString();

                byte[] encodedPrivateKey = Base64.decode(keyString, Base64.DEFAULT);

                try {
                    ASN1Sequence primitive = (ASN1Sequence) ASN1Sequence
                            .fromByteArray(encodedPrivateKey);
                    Enumeration<?> e = primitive.getObjects();
                    BigInteger v = ((ASN1Integer) e.nextElement()).getValue();

                    int version = v.intValue();
                    if (version != 0 && version != 1) {
                        throw new IllegalArgumentException("wrong version for RSA private key");
                    }
                    /**
                     * In fact only modulus and private exponent are in use.
                     */
                    BigInteger modulus = ((ASN1Integer) e.nextElement()).getValue();
                    BigInteger publicExponent = ((ASN1Integer) e.nextElement()).getValue();
                    BigInteger privateExponent = ((ASN1Integer) e.nextElement()).getValue();

                    RSAPrivateKeySpec spec = new RSAPrivateKeySpec(modulus, privateExponent);
                    KeyFactory kf = KeyFactory.getInstance("RSA");
                    return kf.generatePrivate(spec);
                } catch (IOException e2) {
                    throw new IllegalStateException();
                } catch (NoSuchAlgorithmException e) {
                    throw new IllegalStateException(e);
                } catch (InvalidKeySpecException e) {
                    throw new IllegalStateException(e);
                }

        }

从PEM BASE64编码的私钥文件中获取RSA私钥

JAVA RSA解密不起作用，引发InvalidKeySpecException

将PEM传统私钥转换为PKCS8私钥