Java數字證書對文件/加密/解密/簽名/校驗簽名

CertificateUtils.java

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.Date;

import javax.crypto.Cipher;

/**
 * <p>
 * 數字簽名/加密解密工具包
 * </p>
 * 
 * @author IceWee
 * @date 2012-4-26
 * @version 1.0
 */
public class CertificateUtils {

    /**
     * Java密鑰庫(Java 密鑰庫，JKS)KEY_STORE
     */
    public static final String KEY_STORE = "JKS";

    public static final String X509 = "X.509";

    /**
     * 文件讀取緩衝區大小
     */
    private static final int CACHE_SIZE = 2048;

    /**
     * 最大文件加密塊
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;

    /**
     * 最大文件解密塊
     */
    private static final int MAX_DECRYPT_BLOCK = 128;

    /**
     * <p>
     * 根據密鑰庫得到私鑰
     * </p>
     * 
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    private static PrivateKey getPrivateKey(String keyStorePath, String alias, String password) 
            throws Exception {
        KeyStore keyStore = getKeyStore(keyStorePath, password);
        PrivateKey privateKey = (PrivateKey) keyStore.getKey(alias, password.toCharArray());
        return privateKey;
    }

    /**
     * <p>
     * 得到密鑰庫
     * </p>
     * 
     * @param keyStorePath 密鑰庫存儲路徑
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    private static KeyStore getKeyStore(String keyStorePath, String password)
            throws Exception {
        FileInputStream in = new FileInputStream(keyStorePath);
        KeyStore keyStore = KeyStore.getInstance(KEY_STORE);
        keyStore.load(in, password.toCharArray());
        in.close();
        return keyStore;
    }

    /**
     * <p>
     * 根據證書得到公鑰
     * </p>
     * 
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    private static PublicKey getPublicKey(String certificatePath)
            throws Exception {
        Certificate certificate = getCertificate(certificatePath);
        PublicKey publicKey = certificate.getPublicKey();
        return publicKey;
    }

    /**
     * <p>
     * 得到證書
     * </p>
     * 
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    private static Certificate getCertificate(String certificatePath)
            throws Exception {
        CertificateFactory certificateFactory = CertificateFactory.getInstance(X509);
        FileInputStream in = new FileInputStream(certificatePath);
        Certificate certificate = certificateFactory.generateCertificate(in);
        in.close();
        return certificate;
    }

    /**
     * <p>
     * 根據密鑰庫得到證書
     * </p>
     * 
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    private static Certificate getCertificate(String keyStorePath, String alias, String password) 
            throws Exception {
        KeyStore keyStore = getKeyStore(keyStorePath, password);
        Certificate certificate = keyStore.getCertificate(alias);
        return certificate;
    }

    /**
     * <p>
     * 私鑰加密
     * </p>
     * 
     * @param data 源數據
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String keyStorePath, String alias, String password) 
            throws Exception {
        // 取得私鑰
        PrivateKey privateKey = getPrivateKey(keyStorePath, alias, password);
        Cipher cipher = Cipher.getInstance(privateKey.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 對數據分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * <p>
     * 文件私鑰加密
     * </p>
     * <p>
     * 過大的文件可能會致使內存溢出
     * </>
     * 
     * @param filePath 文件路徑
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    public static byte[] encryptFileByPrivateKey(String filePath, String keyStorePath, String alias, String password) 
            throws Exception {
        byte[] data = fileToByte(filePath);
        return encryptByPrivateKey(data, keyStorePath, alias, password);
    }

    /**
     * <p>
     * 文件加密
     * </p>
     * 
     * @param srcFilePath 源文件
     * @param destFilePath 加密後文件
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @throws Exception
     */
    public static void encryptFileByPrivateKey(String srcFilePath, String destFilePath, String keyStorePath, String alias, String password)
            throws Exception {
        // 取得私鑰
        PrivateKey privateKey = getPrivateKey(keyStorePath, alias, password);
        Cipher cipher = Cipher.getInstance(privateKey.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
        File srcFile = new File(srcFilePath);
        FileInputStream in = new FileInputStream(srcFile);
        File destFile = new File(destFilePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();
        OutputStream out = new FileOutputStream(destFile);   
        byte[] data = new byte[MAX_ENCRYPT_BLOCK];
        byte[] encryptedData;    // 加密塊
        while (in.read(data) != -1) {
            encryptedData = cipher.doFinal(data);
            out.write(encryptedData, 0, encryptedData.length);
            out.flush();
        }
        out.close();
        in.close();
    }

    /**
     * <p>
     * 文件加密成BASE64編碼的字符串
     * </p>
     * 
     * @param filePath 文件路徑
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    public static String encryptFileToBase64ByPrivateKey(String filePath, String keyStorePath, String alias, String password) 
            throws Exception {
        byte[] encryptedData = encryptFileByPrivateKey(filePath, keyStorePath, alias, password);
        return Base64Utils.encode(encryptedData);
    }

    /**
     * <p>
     * 私鑰解密
     * </p>
     * 
     * @param encryptedData 已加密數據
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String keyStorePath, String alias, String password) 
            throws Exception {
        // 取得私鑰
        PrivateKey privateKey = getPrivateKey(keyStorePath, alias, password);
        Cipher cipher = Cipher.getInstance(privateKey.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        // 解密byte數組最大長度限制: 128
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 對數據分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 公鑰加密
     * </p>
     * 
     * @param data 源數據
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String certificatePath)
            throws Exception {
        // 取得公鑰
        PublicKey publicKey = getPublicKey(certificatePath);
        Cipher cipher = Cipher.getInstance(publicKey.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 對數據分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * <p>
     * 公鑰解密
     * </p>
     * 
     * @param encryptedData 已加密數據
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String certificatePath)
            throws Exception {
        PublicKey publicKey = getPublicKey(certificatePath);
        Cipher cipher = Cipher.getInstance(publicKey.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicKey);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 對數據分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 文件解密
     * </p>
     * 
     * @param srcFilePath 源文件
     * @param destFilePath 目標文件
     * @param certificatePath 證書存儲路徑
     * @throws Exception
     */
    public static void decryptFileByPublicKey(String srcFilePath, String destFilePath, String certificatePath)
            throws Exception {
        PublicKey publicKey = getPublicKey(certificatePath);
        Cipher cipher = Cipher.getInstance(publicKey.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicKey);
        File srcFile = new File(srcFilePath);
        FileInputStream in = new FileInputStream(srcFile);
        File destFile = new File(destFilePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();
        OutputStream out = new FileOutputStream(destFile);   
        byte[] data = new byte[MAX_DECRYPT_BLOCK];
        byte[] decryptedData;    // 解密塊
        while (in.read(data) != -1) {
            decryptedData = cipher.doFinal(data);
            out.write(decryptedData, 0, decryptedData.length); 
            out.flush();
        }
        out.close();
        in.close();
    }

    /**
     * <p>
     * 生成數據簽名
     * </p>
     * 
     * @param data 源數據
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    public static byte[] sign(byte[] data, String keyStorePath, String alias, String password) 
            throws Exception {
        // 得到證書
        X509Certificate x509Certificate = (X509Certificate) getCertificate(keyStorePath, alias, password);
        // 獲取私鑰
        KeyStore keyStore = getKeyStore(keyStorePath, password);
        // 取得私鑰
        PrivateKey privateKey = (PrivateKey) keyStore.getKey(alias, password.toCharArray());
        // 構建簽名
        Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
        signature.initSign(privateKey);
        signature.update(data);
        return signature.sign();
    }

    /**
     * <p>
     * 生成數據簽名並以BASE64編碼
     * </p>
     * 
     * @param data 源數據
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    public static String signToBase64(byte[] data, String keyStorePath, String alias, String password) 
            throws Exception {
        return Base64Utils.encode(sign(data, keyStorePath, alias, password));
    }

    /**
     * <p>
     * 生成文件數據簽名(BASE64)
     * </p>
     * <p>
     * 須要先將文件私鑰加密，再根據加密後的數據生成簽名(BASE64)，適用於小文件
     * </p>
     * 
     * @param filePath 源文件
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    public static String signFileToBase64WithEncrypt(String filePath, String keyStorePath, String alias, String password)
            throws Exception {
        byte[] encryptedData = encryptFileByPrivateKey(filePath, keyStorePath, alias, password);
        return signToBase64(encryptedData, keyStorePath, alias, password);
    }

    /**
     * <p>
     * 生成文件簽名
     * </p>
     * <p>
     * 注意：<br>
     * 方法中使用了FileChannel，其巨大Bug就是不會釋放文件句柄，致使簽名的文件沒法操做(移動或刪除等)<br>
     * 該方法已被generateFileSign取代
     * </p>
     * 
     * @param filePath 文件路徑
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     * @throws Exception
     */
    @Deprecated
    public static byte[] signFile(String filePath, String keyStorePath, String alias, String password)
            throws Exception {
        byte[] sign = new byte[0];
        // 得到證書
        X509Certificate x509Certificate = (X509Certificate) getCertificate(keyStorePath, alias, password);
        // 獲取私鑰
        KeyStore keyStore = getKeyStore(keyStorePath, password);
        // 取得私鑰
        PrivateKey privateKey = (PrivateKey) keyStore.getKey(alias, password.toCharArray());
        // 構建簽名
        Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
        signature.initSign(privateKey);
        File file = new File(filePath);
        if (file.exists()) {
            FileInputStream in = new FileInputStream(file);
            FileChannel fileChannel = in.getChannel();
            MappedByteBuffer byteBuffer = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
            signature.update(byteBuffer);
            fileChannel.close();
            in.close();
            sign = signature.sign();
         }
        return sign;
    }

    /**
     * <p>
     * 生成文件數字簽名
     * </p>
     * 
      * <p>
     * <b>注意：</b><br>
     * 生成簽名時update的byte數組大小和驗證簽名時的大小應相同，不然驗證沒法經過
     * </p>
     * 
     * @param filePath
     * @param keyStorePath
     * @param alias
     * @param password
     * @return
     * @throws Exception
     */
    public static byte[] generateFileSign(String filePath, String keyStorePath, String alias, String password)
            throws Exception {
        byte[] sign = new byte[0];
        // 得到證書
        X509Certificate x509Certificate = (X509Certificate) getCertificate(keyStorePath, alias, password);
        // 獲取私鑰
        KeyStore keyStore = getKeyStore(keyStorePath, password);
        // 取得私鑰
        PrivateKey privateKey = (PrivateKey) keyStore.getKey(alias, password.toCharArray());
        // 構建簽名
        Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
        signature.initSign(privateKey);
        File file = new File(filePath);
        if (file.exists()) {
            FileInputStream in = new FileInputStream(file);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                signature.update(cache, 0, nRead);
            }
            in.close();
            sign = signature.sign();
         }
        return sign;
    }

    /**
     * <p>
     * 文件簽名成BASE64編碼字符串
     * </p>
     * 
     * @param filePath
     * @param keyStorePath
     * @param alias
     * @param password
     * @return
     * @throws Exception
     */
    public static String signFileToBase64(String filePath, String keyStorePath, String alias, String password)
            throws Exception {
        return Base64Utils.encode(generateFileSign(filePath, keyStorePath, alias, password));
    }

    /**
     * <p>
     * 驗證簽名
     * </p>
     * 
     * @param data 已加密數據
     * @param sign 數據簽名[BASE64]
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    public static boolean verifySign(byte[] data, String sign, String certificatePath) 
            throws Exception {
        // 得到證書
        X509Certificate x509Certificate = (X509Certificate) getCertificate(certificatePath);
        // 得到公鑰
        PublicKey publicKey = x509Certificate.getPublicKey();
        // 構建簽名
        Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
        signature.initVerify(publicKey);
        signature.update(data);
        return signature.verify(Base64Utils.decode(sign));
    }

    /**
     * <p>
     * 校驗文件完整性
     * </p>
     * <p>
     * 鑑於FileChannel存在的巨大Bug，該方法已停用，被validateFileSign取代
     * </p>
     * 
     * @param filePath 文件路徑
     * @param sign 數據簽名[BASE64]
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    @Deprecated
    public static boolean verifyFileSign(String filePath, String sign, String certificatePath) 
            throws Exception {
        boolean result = false;
        // 得到證書
        X509Certificate x509Certificate = (X509Certificate) getCertificate(certificatePath);
        // 得到公鑰
        PublicKey publicKey = x509Certificate.getPublicKey();
        // 構建簽名
        Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
        signature.initVerify(publicKey);
        File file = new File(filePath);
        if (file.exists()) {
            byte[] decodedSign = Base64Utils.decode(sign);
            FileInputStream in = new FileInputStream(file);
            FileChannel fileChannel = in.getChannel();
            MappedByteBuffer byteBuffer = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
            signature.update(byteBuffer);
            in.close();
            result = signature.verify(decodedSign);
         }
        return result;
    }

    /**
     * <p>
     * 校驗文件簽名
     * </p>
     * 
     * @param filePath
     * @param sign
     * @param certificatePath
     * @return
     * @throws Exception
     */
    public static boolean validateFileSign(String filePath, String sign, String certificatePath) 
            throws Exception {
        boolean result = false;
        // 得到證書
        X509Certificate x509Certificate = (X509Certificate) getCertificate(certificatePath);
        // 得到公鑰
        PublicKey publicKey = x509Certificate.getPublicKey();
        // 構建簽名
        Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
        signature.initVerify(publicKey);
        File file = new File(filePath);
        if (file.exists()) {
            byte[] decodedSign = Base64Utils.decode(sign);
            FileInputStream in = new FileInputStream(file);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                signature.update(cache, 0, nRead);
            }
            in.close();
            result = signature.verify(decodedSign);
         }
        return result;
    }

    /**
     * <p>
     * BASE64解碼->簽名校驗
     * </p>
     * 
     * @param base64String BASE64編碼字符串
     * @param sign 數據簽名[BASE64]
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    public static boolean verifyBase64Sign(String base64String, String sign, String certificatePath) 
            throws Exception {
        byte[] data = Base64Utils.decode(base64String);
        return verifySign(data, sign, certificatePath);
    }

    /**
     * <p>
     * BASE64解碼->公鑰解密-簽名校驗
     * </p>
     * 
     * 
     * @param base64String BASE64編碼字符串
     * @param sign 數據簽名[BASE64]
     * @param certificatePath 證書存儲路徑
     * @return
     * @throws Exception
     */
    public static boolean verifyBase64SignWithDecrypt(String base64String, String sign, String certificatePath) 
            throws Exception {
        byte[] encryptedData = Base64Utils.decode(base64String);
        byte[] data = decryptByPublicKey(encryptedData, certificatePath);
        return verifySign(data, sign, certificatePath);
    }

    /**
     * <p>
     * 文件公鑰解密->簽名校驗
     * </p>
     * 
     * @param encryptedFilePath 加密文件路徑
     * @param sign 數字證書[BASE64]
     * @param certificatePath
     * @return
     * @throws Exception
     */
    public static boolean verifyFileSignWithDecrypt(String encryptedFilePath, String sign, String certificatePath)
            throws Exception {
        byte[] encryptedData = fileToByte(encryptedFilePath);
        byte[] data =  decryptByPublicKey(encryptedData, certificatePath);
        return verifySign(data, sign, certificatePath);
    }

    /**
     * <p>
     * 校驗證書當前是否有效
     * </p>
     * 
     * @param certificate 證書
     * @return
     */
    public static boolean verifyCertificate(Certificate certificate) {
        return verifyCertificate(new Date(), certificate);
    }

    /**
     * <p>
     * 驗證證書是否過時或無效
     * </p>
     * 
     * @param date 日期
     * @param certificate 證書
     * @return
     */
    public static boolean verifyCertificate(Date date, Certificate certificate) {
        boolean isValid = true;
        try {
            X509Certificate x509Certificate = (X509Certificate) certificate;
            x509Certificate.checkValidity(date);
        } catch (Exception e) {
            isValid = false;
        }
        return isValid;
    }

    /**
     * <p>
     * 驗證數字證書是在給定的日期是否有效
     * </p>
     * 
     * @param date 日期
     * @param certificatePath 證書存儲路徑
     * @return
     */
    public static boolean verifyCertificate(Date date, String certificatePath) {
        Certificate certificate;
        try {
            certificate = getCertificate(certificatePath);
            return verifyCertificate(certificate);
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * <p>
     * 驗證數字證書是在給定的日期是否有效
     * </p>
     * 
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     */
    public static boolean verifyCertificate(Date date, String keyStorePath, String alias, String password) {
        Certificate certificate;
        try {
            certificate = getCertificate(keyStorePath, alias, password);
            return verifyCertificate(certificate);
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * <p>
     * 驗證數字證書當前是否有效
     * </p>
     * 
     * @param keyStorePath 密鑰庫存儲路徑
     * @param alias 密鑰庫別名
     * @param password 密鑰庫密碼
     * @return
     */
    public static boolean verifyCertificate(String keyStorePath, String alias, String password) {
        return verifyCertificate(new Date(), keyStorePath, alias, password);
    }

    /**
     * <p>
     * 驗證數字證書當前是否有效
     * </p>
     * 
     * @param certificatePath 證書存儲路徑
     * @return
     */
    public static boolean verifyCertificate(String certificatePath) {
        return verifyCertificate(new Date(), certificatePath);
    }

    /**
     * <p>
     * 文件轉換爲byte數組
     * </p>
     * 
     * @param filePath 文件路徑
     * @return
     * @throws Exception
     */
    public static byte[] fileToByte(String filePath) throws Exception {
        byte[] data = new byte[0];
        File file = new File(filePath);
        if (file.exists()) {
            FileInputStream in = new FileInputStream(file);
            ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            in.close();
            data = out.toByteArray();
         }
        return data;
    }

    /**
     * <p>
     * 二進制數據寫文件
     * </p>
     * 
     * @param bytes 二進制數據
     * @param filePath 文件生成目錄
     */
    public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
        InputStream in = new ByteArrayInputStream(bytes);   
        File destFile = new File(filePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();
        OutputStream out = new FileOutputStream(destFile);
        byte[] cache = new byte[CACHE_SIZE];
        int nRead = 0;
        while ((nRead = in.read(cache)) != -1) {   
            out.write(cache, 0, nRead);
            out.flush();
        }
        out.close();
        in.close();
    }

}

CertificateTester.java

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

public class CertificateTester {

    private static final String KEY_STORE_NAME = "asdc.keystore";
    private static final String CERTIFICATE_NAME = "asdc.cer";
    private static final String password = "123456";
    private static final String alias = "www.asdc.com.cn";
    private static String certificatePath;
    private static String keyStorePath;

    static {
        String currentDir = CertificateTester.class.getResource("").getPath();
        if (currentDir.startsWith("/"))
            currentDir = currentDir.substring(1);
        if (!currentDir.endsWith("/")) 
            currentDir += "/";
        keyStorePath = currentDir + KEY_STORE_NAME;
        certificatePath = currentDir + CERTIFICATE_NAME;
    }

    public static void main(String[] args) throws Exception {
        simple();
        simpleSign();
        testFileSign();
    }

    static void simple() throws Exception {
        System.err.println("公鑰加密——私鑰解密");
        String source = "這是一行沒有任何意義的文字，你看完了等於沒看，不是嗎？";
        byte[] data = source.getBytes();

        byte[] encrypt = CertificateUtils.encryptByPublicKey(data, certificatePath);

        byte[] decrypt = CertificateUtils.decryptByPrivateKey(encrypt, keyStorePath, alias, password);
        String outputStr = new String(decrypt);

        System.out.println("加密前: \r\n" + source + "\r\n" + "解密後: \r\n" + outputStr);

        // 驗證數據一致
        assertArrayEquals(data, decrypt);

        // 驗證證書有效
        assertTrue(CertificateUtils.verifyCertificate(certificatePath));
    }

    static void simpleSign() throws Exception {
        System.err.println("私鑰加密——公鑰解密");

        String source = "這是一行簽名的測試文字";
        byte[] data = source.getBytes();

        byte[] encodedData = CertificateUtils.encryptByPrivateKey(data, keyStorePath, alias, password);

        byte[] decodedData = CertificateUtils.decryptByPublicKey(encodedData, certificatePath);

        String target = new String(decodedData);
        System.out.println("加密前: \r\n" + source + "\r\n" + "解密後: \r\n" + target);
        assertEquals(source, target);

        System.err.println("私鑰簽名——公鑰驗證簽名");
        // 產生簽名
        String sign = CertificateUtils.signToBase64(encodedData, keyStorePath, alias, password);
        System.out.println("簽名:\r\n" + sign);

        // 驗證簽名
        boolean status = CertificateUtils.verifySign(encodedData, sign, certificatePath);
        System.err.println("狀態:\r\n" + status);
        assertTrue(status);
    }

    static void testFileSign() throws Exception {
        String filePath = "D:/software/eclipse-SDK-3.3.2-win32.zip";
        String sign = CertificateUtils.signFileToBase64(filePath, keyStorePath, alias, password);
        System.err.println("生成簽名：\r\n" + sign);
        boolean result = CertificateUtils.verifyFileSign(filePath, sign, certificatePath);
        System.err.println("校驗結果：" + result);
    }

}