使用缓冲区计算大文件的 SHA-512 hash

Question

我正在使用混合密码术，我对一个大文件的 hash 进行加密，然后对其进行验证，但是每次我得到不同的 hash 时。我在这里做错了什么？

public static void main(String[] args) throws Exception {
        HybridCryptographyE ac = new HybridCryptographyE();
        PrivateKey privateKey = ac.getPrivate("KeyPair/Source/privateKey");
        PublicKey publicKey = ac.getPublic("KeyPair/Source/publicKey");

        //Step 2 Generate Key and IV----------------

        File directory = new File("/Users/aviral/Desktop/AES/SourceFile/");
        File[] fList = directory.listFiles();
        for (File file : fList){
            String inFile = file.toString();
            String outFile = file.toString().replace("SourceFile", "EncResult");    
            //Step1 Calculating hash here 
            Cipher cipher = Cipher.getInstance("AES/GCM/PKCS5Padding");
            KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
            keyGenerator.init(AES_KEY_SIZE);
            SecretKey key = keyGenerator.generateKey();
            byte[] IV = new byte[GCM_IV_LENGTH];
            SecureRandom random = new SecureRandom();
            random.nextBytes(IV);
            SecretKeySpec keySpec = new SecretKeySpec(key.getEncoded(), "AES");
            GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(GCM_TAG_LENGTH * 8, IV);
            cipher.init(Cipher.ENCRYPT_MODE, keySpec, gcmParameterSpec);

            String hash=processFile(cipher, inFile, outFile);
            //Step 3 Encrypt the hash generated in step 1 using the PvKS
            String encrypted_msg = ac.encryptText(hash, privateKey);
            System.out.println("Hash of file "+hash);
            System.out.println("Encrypted Hash of file "+encrypted_msg);

            //Step 5 
            String encodedKey=Base64.getEncoder().encodeToString(key.getEncoded()); 
            String encodedIV=Base64.getEncoder().encodeToString(IV);            
            String encodedtag=Base64.getEncoder().encodeToString("".getBytes());
            System.out.println("ImpDataComing");
            System.out.println(encodedKey);
            System.out.println(encodedIV); 
            System.out.println(encodedtag);

            String infodata=encodedKey+"|*|"+encodedIV+"|*|"+encodedtag;
            System.out.println("InfoData");
            System.out.println(infodata);
            String infodata_enc = ac.encryptText(infodata, publicKey);
            System.out.println("InfoData_Enc");
            System.out.println(infodata_enc);

            String finalproperwrite=encrypted_msg+"\n"+infodata_enc;

            //Step 6 
            FileUtils.writeByteArrayToFile(new File(file.toString().replace("SourceFile", "EncResult")+".info"),finalproperwrite.toString().getBytes());
            System.out.println("Step 1 Hash  of text is "+hash);
            System.out.println("Step 2 Encrypted hash is "+encrypted_msg);
            System.out.println("Step 3 Files Generated ");
        }

    }
    static private String processFile(Cipher ci,String inFile,String outFile)
            throws javax.crypto.IllegalBlockSizeException,
            javax.crypto.BadPaddingException,
            java.io.IOException, NoSuchAlgorithmException
    {
        MessageDigest mdb = MessageDigest.getInstance("SHA-512");
        try (FileInputStream in = new FileInputStream(inFile);
                FileOutputStream out = new FileOutputStream(outFile)) {
            byte[] ibuf = new byte[8192];
            int len;
            while ((len = in.read(ibuf)) != -1) {
                mdb.update(ibuf);
                byte[] obuf = ci.update(ibuf, 0, len);          
                if ( obuf != null ) out.write(obuf);
            }
            //Step 4 Encrypt the INPUTFILE using AES Key and IV
            byte[] obuf = ci.doFinal();
            byte[] messageDigestbuf =mdb.digest(obuf);
            if ( obuf != null ) out.write(obuf);
            BigInteger nob = new BigInteger(1, messageDigestbuf);
            String hashtextb = nob.toString(16); 
            while (hashtextb.length() < 32) { 
                hashtextb = "0" + hashtextb;


            }
            return hashtextb;
        }


    }

}

在解密期间 hash 计算与我的代码不匹配。我还注意到 hash 值不同。我是这个的初学者，请帮助