eN61ECQN

1import android.content.Context;
2import android.util.Base64;
3
4import java.io.InputStream;
5import java.security.PublicKey;
6import java.security.SecureRandom;
7import java.security.cert.CertificateFactory;
8import java.security.cert.X509Certificate;
9
10import javax.crypto.Cipher;
11import javax.crypto.KeyGenerator;
12import javax.crypto.Mac;
13import javax.crypto.SecretKey;
14import javax.crypto.spec.IvParameterSpec;
15import javax.crypto.spec.SecretKeySpec;
16
17/**
18 * Created by chenfeng on 16/4/5.
19 */
20public class CertManager {
21
22    /**
23     * 产生随机密钥
24     *
25     * @param size 长度
26     * @return 随机密钥
27     */
28    public static byte[] getRandom(int size) throws Exception {
29        KeyGenerator kgen = KeyGenerator.getInstance("AES");
30        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
31        kgen.init(size * 8, sr);
32        SecretKey sKey = kgen.generateKey();
33        byte[] raw = sKey.getEncoded();
34        return raw;
35
36    }
37
38
39    /**
40     * 从domain.crt中获取公钥
41     *
42     * @param context
43     * @return
44     */
45    public static PublicKey getPublicKey(Context context) throws Exception {
46        //从raw中读取证书文件
47        InputStream is = context.getResources().openRawResource(R.raw.domain);
48        //创建X509工厂类
49        CertificateFactory cf = CertificateFactory.getInstance("X.509");
50        //创建证书对象
51        X509Certificate cert = (X509Certificate) cf.generateCertificate(is);
52        //获取公钥
53        PublicKey publicKey = cert.getPublicKey();
54        //关闭输入流
55        is.close();
56        return publicKey;
57
58    }
59
60
61    /**
62     * 对要加密的报文plainText使用AES-CBC加密，得到加密后的报文并base64编码
63     *
64     * @param randomKey 随机密钥
65     * @param plainText 待加密的字符串
66     * @return 加密并B64转码后的字节数组
67     */
68    public static byte[] encryptByRandomKey(byte[] randomKey, String plainText) throws Exception {
69
70        byte[] AESKey = CertManager.subBytes(randomKey, 0, 32);//前32位作为AES的KEY
71        byte[] iv = CertManager.subBytes(randomKey, 32, 16);//后16位作为AES的IV
72
73        SecretKeySpec spec = new SecretKeySpec(AESKey, "AES");
74        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");//"算法/模式/补码方式"
75        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
76        cipher.init(Cipher.ENCRYPT_MODE, spec, ivParameterSpec);
77        byte[] encrypted = cipher.doFinal(plainText.getBytes("UTF-8"));
78        return Base64.encode(encrypted, Base64.NO_WRAP);
79    }
80
81
82    /**
83     * 使用公钥证书加密并base64编码
84     *
85     * @param key       证书公钥
86     * @param plainText 待加密数据
87     * @return 加密并B64转码后的字节数组
88     */
89    public static byte[] encryptByPublciKey(PublicKey key, byte[] plainText) throws Exception {
90        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");//"算法/模式/补码方式"
91        cipher.init(Cipher.ENCRYPT_MODE, key);
92        byte[] encrypted = cipher.doFinal(plainText);
93        return Base64.encode(encrypted, Base64.NO_WRAP);
94
95    }
96
97
98    /**
99     * 创建HMAC签名
100     *
101     * @param encryptedBody 待签名数据
102     * @param accessSecret  Secret
103     * @return 签名并且Base64后的字符串
104     */
105    public static String hmacSha256(byte[] encryptedBody, String accessSecret) throws Exception {
106        Mac mac = Mac.getInstance("HmacSHA256");
107        SecretKey secret = new SecretKeySpec(accessSecret.getBytes("UTF-8"), "HMACSHA256");
108        mac.init(secret);
109        byte[] bytes = mac.doFinal(encryptedBody);
110        return Base64.encodeToString(bytes, Base64.NO_WRAP);
111
112    }
113
114
115    /**
116     * 从一个byte[]数组中截取一部分
117     *
118     * @param src
119     * @param begin
120     * @param count
121     * @return
122     */
123    public static byte[] subBytes(byte[] src, int begin, int count) {
124        byte[] bs = new byte[count];
125        for (int i = begin; i < begin + count; i++) bs[i - begin] = src[i];
126        return bs;
127    }
128
129}