【开源项目】Android下RSA加密与解密

概述RSAUtilspackagecom.example.rsa;importjava.io.BufferedReader;importjava.io.IOException;importjava.io.InputStream;importjava.io.InputStreamReader;importjava.math.BigInteger;importjava.security.KeyFactory;importjava.security.KeyPair;import

RSAUtils

package com.example.rsa;import java.io.BufferedReader;import java.io.IOException;import java.io.inputStream;import java.io.inputStreamReader;import java.math.BigInteger;import java.security.KeyFactory;import java.security.KeyPair;import java.security.KeyPairGenerator;import java.security.NoSuchAlgorithmException;import java.security.PrivateKey;import java.security.PublicKey;import java.security.interfaces.RSAPrivateKey;import java.security.interfaces.RSAPublicKey;import java.security.spec.InvalIDKeySpecException;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.RSAPublicKeySpec;import java.security.spec.X509EncodedKeySpec;import javax.crypto.Cipher;public final class RSAUtils{    private static String RSA = "RSA";    /**     * 随机生成RSA密钥对(默认密钥长度为1024)     *     * @return     */    public static KeyPair generateRSAKeyPair()    {        return generateRSAKeyPair(1024);    }    /**     * 随机生成RSA密钥对     *     * @param keyLength     *            密钥长度，范围：512～2048<br>     *            一般1024     * @return     */    public static KeyPair generateRSAKeyPair(int keyLength)    {        try        {            KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA);            kpg.initialize(keyLength);            return kpg.genKeyPair();        } catch (NoSuchAlgorithmException e)        {            e.printstacktrace();            return null;        }    }    /**     * 用公钥加密 <br>     * 每次加密的字节数，不能超过密钥的长度值减去11     *     * @param data     *            需加密数据的byte数据     * @param publicKey     *            公钥     * @return 加密后的byte型数据     */    public static byte[] encryptData(byte[] data, PublicKey publicKey)    {        try        {            Cipher cipher = Cipher.getInstance(RSA);            // 编码前设定编码方式及密钥            cipher.init(Cipher.ENCRYPT_MODE, publicKey);            // 传入编码数据并返回编码结果            return cipher.doFinal(data);        } catch (Exception e)        {            e.printstacktrace();            return null;        }    }    /**     * 用私钥解密     *     * @param encryptedData     *            经过encryptedData()加密返回的byte数据     * @param privateKey     *            私钥     * @return     */    public static byte[] decryptData(byte[] encryptedData, PrivateKey privateKey)    {        try        {            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1padding");            cipher.init(Cipher.DECRYPT_MODE, privateKey);            return cipher.doFinal(encryptedData);        } catch (Exception e)        {            return null;        }    }    /**     * 通过公钥byte[](publicKey.getEncoded())将公钥还原，适用于RSA算法     *     * @param keyBytes     * @return     * @throws NoSuchAlgorithmException     * @throws InvalIDKeySpecException     */    public static PublicKey getPublicKey(byte[] keyBytes) throws NoSuchAlgorithmException,            InvalIDKeySpecException    {        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PublicKey publicKey = keyFactory.generatePublic(keySpec);        return publicKey;    }    /**     * 通过私钥byte[]将公钥还原，适用于RSA算法     *     * @param keyBytes     * @return     * @throws NoSuchAlgorithmException     * @throws InvalIDKeySpecException     */    public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException,            InvalIDKeySpecException    {        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);        return privateKey;    }    /**     * 使用N、e值还原公钥     *     * @param modulus     * @param publicExponent     * @return     * @throws NoSuchAlgorithmException     * @throws InvalIDKeySpecException     */    public static PublicKey getPublicKey(String modulus, String publicExponent)            throws NoSuchAlgorithmException, InvalIDKeySpecException    {        BigInteger bigIntModulus = new BigInteger(modulus);        BigInteger bigIntPrivateExponent = new BigInteger(publicExponent);        RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PublicKey publicKey = keyFactory.generatePublic(keySpec);        return publicKey;    }    /**     * 使用N、d值还原私钥     *     * @param modulus     * @param privateExponent     * @return     * @throws NoSuchAlgorithmException     * @throws InvalIDKeySpecException     */    public static PrivateKey getPrivateKey(String modulus, String privateExponent)            throws NoSuchAlgorithmException, InvalIDKeySpecException    {        BigInteger bigIntModulus = new BigInteger(modulus);        BigInteger bigIntPrivateExponent = new BigInteger(privateExponent);        RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);        KeyFactory keyFactory = KeyFactory.getInstance(RSA);        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);        return privateKey;    }    /**     * 从字符串中加载公钥     *     * @param publicKeyStr     *            公钥数据字符串     * @throws Exception     *             加载公钥时产生的异常     */    public static PublicKey loadPublicKey(String publicKeyStr) throws Exception    {        try        {            byte[] buffer = Base64Utils.decode(publicKeyStr);            KeyFactory keyFactory = KeyFactory.getInstance(RSA);            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);            return (RSAPublicKey) keyFactory.generatePublic(keySpec);        } catch (NoSuchAlgorithmException e)        {            throw new Exception("无此算法");        } catch (InvalIDKeySpecException e)        {            throw new Exception("公钥非法");        } catch (NullPointerException e)        {            throw new Exception("公钥数据为空");        }    }    /**     * 从字符串中加载私钥<br>     * 加载时使用的是PKCS8EncodedKeySpec（PKCS#8编码的Key指令）。     *     * @param privateKeyStr     * @return     * @throws Exception     */    public static PrivateKey loadPrivateKey(String privateKeyStr) throws Exception    {        try        {            byte[] buffer = Base64Utils.decode(privateKeyStr);            // X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);            KeyFactory keyFactory = KeyFactory.getInstance(RSA);            return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);        } catch (NoSuchAlgorithmException e)        {            throw new Exception("无此算法");        } catch (InvalIDKeySpecException e)        {            throw new Exception("私钥非法");        } catch (NullPointerException e)        {            throw new Exception("私钥数据为空");        }    }    /**     * 从文件中输入流中加载公钥     *     * @param in     *            公钥输入流     * @throws Exception     *             加载公钥时产生的异常     */    public static PublicKey loadPublicKey(inputStream in) throws Exception    {        try        {            return loadPublicKey(readKey(in));        } catch (IOException e)        {            throw new Exception("公钥数据流读取错误");        } catch (NullPointerException e)        {            throw new Exception("公钥输入流为空");        }    }    /**     * 从文件中加载私钥     *     * @param in     *            私钥文件名     * @return 是否成功     * @throws Exception     */    public static PrivateKey loadPrivateKey(inputStream in) throws Exception    {        try        {            return loadPrivateKey(readKey(in));        } catch (IOException e)        {            throw new Exception("私钥数据读取错误");        } catch (NullPointerException e)        {            throw new Exception("私钥输入流为空");        }    }    /**     * 读取密钥信息     *     * @param in     * @return     * @throws IOException     */    private static String readKey(inputStream in) throws IOException    {        BufferedReader br = new BufferedReader(new inputStreamReader(in));        String readline = null;        StringBuilder sb = new StringBuilder();        while ((readline = br.readline()) != null)        {            if (readline.charat(0) == '-')            {                continue;            } else            {                sb.append(readline);                sb.append('\r');            }        }        return sb.toString();    }    /**     * 打印公钥信息     *     * @param publicKey     */    public static voID printPublicKeyInfo(PublicKey publicKey)    {        RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey;        System.out.println("----------RSAPublicKey----------");        System.out.println("Modulus.length=" + rsaPublicKey.getModulus().bitLength());        System.out.println("Modulus=" + rsaPublicKey.getModulus().toString());        System.out.println("PublicExponent.length=" + rsaPublicKey.getPublicExponent().bitLength());        System.out.println("PublicExponent=" + rsaPublicKey.getPublicExponent().toString());    }    public static voID printPrivateKeyInfo(PrivateKey privateKey)    {        RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey;        System.out.println("----------RSAPrivateKey ----------");        System.out.println("Modulus.length=" + rsaPrivateKey.getModulus().bitLength());        System.out.println("Modulus=" + rsaPrivateKey.getModulus().toString());        System.out.println("PrivateExponent.length=" + rsaPrivateKey.getPrivateExponent().bitLength());        System.out.println("PrivatecExponent=" + rsaPrivateKey.getPrivateExponent().toString());    }}

Base64Utils

package com.example.rsa;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.OutputStream;public class Base64Utils {    private static final char[] legalChars = "ABCDEFGHIJKLMnopQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"            .tochararray();    public static String encode(byte[] data) {        int start = 0;        int len = data.length;        StringBuffer buf = new StringBuffer(data.length * 3 / 2);        int end = len - 3;        int i = start;        int n = 0;        while (i <= end) {            int d = ((((int) data[i]) & 0x0ff) << 16)                    | ((((int) data[i + 1]) & 0x0ff) << 8)                    | (((int) data[i + 2]) & 0x0ff);            buf.append(legalChars[(d >> 18) & 63]);            buf.append(legalChars[(d >> 12) & 63]);            buf.append(legalChars[(d >> 6) & 63]);            buf.append(legalChars[d & 63]);            i += 3;            if (n++ >= 14) {                n = 0;                buf.append(" ");            }        }        if (i == start + len - 2) {            int d = ((((int) data[i]) & 0x0ff) << 16)                    | ((((int) data[i + 1]) & 255) << 8);            buf.append(legalChars[(d >> 18) & 63]);            buf.append(legalChars[(d >> 12) & 63]);            buf.append(legalChars[(d >> 6) & 63]);            buf.append("=");        } else if (i == start + len - 1) {            int d = (((int) data[i]) & 0x0ff) << 16;            buf.append(legalChars[(d >> 18) & 63]);            buf.append(legalChars[(d >> 12) & 63]);            buf.append("==");        }        return buf.toString();    }    private static int decode(char c) {        if (c >= 'A' && c <= 'Z')            return ((int) c) - 65;        else if (c >= 'a' && c <= 'z')            return ((int) c) - 97 + 26;        else if (c >= '0' && c <= '9')            return ((int) c) - 48 + 26 + 26;        else            switch (c) {                case '+':                    return 62;                case '/':                    return 63;                case '=':                    return 0;                default:                    throw new RuntimeException("unexpected code: " + c);            }    }    /**     * Decodes the given Base64 encoded String to a new byte array. The byte     * array holding the decoded data is returned.     */    public static byte[] decode(String s) {        ByteArrayOutputStream bos = new ByteArrayOutputStream();        try {            decode(s, bos);        } catch (IOException e) {            throw new RuntimeException();        }        byte[] decodedBytes = bos.toByteArray();        try {            bos.close();            bos = null;        } catch (IOException ex) {            System.err.println("Error while deCoding BASE64: " + ex.toString());        }        return decodedBytes;    }    private static voID decode(String s, OutputStream os) throws IOException {        int i = 0;        int len = s.length();        while (true) {            while (i < len && s.charat(i) <= ' ')                i++;            if (i == len)                break;            int tri = (decode(s.charat(i)) << 18)                    + (decode(s.charat(i + 1)) << 12)                    + (decode(s.charat(i + 2)) << 6)                    + (decode(s.charat(i + 3)));            os.write((tri >> 16) & 255);            if (s.charat(i + 2) == '=')                break;            os.write((tri >> 8) & 255);            if (s.charat(i + 3) == '=')                break;            os.write(tri & 255);            i += 4;        }    }}

Activity中调用

   try        {            // 从字符串中得到私钥            // PrivateKey privateKey = RSAUtils.loadPrivateKey(PRIVATE_KEY);            // 从assets目录下得到私钥            inputStream inPrivate = getResources().getAssets().open("pkcs8_private_key.pem");            PrivateKey privateKey = RSAUtils.loadPrivateKey(inPrivate);            // 因为RSA加密后的内容经Base64再加密转换了一下，所以先Base64解密回来再给RSA解密            String encryptContent = "私钥";            byte[] decryptByte = RSAUtils.decryptData(Base64Utils.decode(encryptContent), privateKey);            String decryptStr = new String(decryptByte);            pc.setText(decryptStr);        } catch (Exception e)        {            e.printstacktrace();        }

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

总结

以上是内存溢出为你收集整理的【开源项目】Android下RSA加密与解密全部内容，希望文章能够帮你解决【开源项目】Android下RSA加密与解密所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。