- How to lock a folder in android without any app generator#
- How to lock a folder in android without any app password#
How to lock a folder in android without any app password#
Use Windows File Encryption Tool to Password Protect Notepad File Here you'll find three reliable ways to keep a Notepad file private with a password. How about the plain Notepad text file? It seems that there is no such a Microsoft Office encryption solution in the Notepad editor. Without a password, nobody can open, view or edit the content in it. For example, in a Word application for Windows, go to File > Info > Protect Document > Encrypt with Password, you'll keep a file under a protected view. Is there any simple but effective way to password protect a Notepad file in Windows 11 or Windows 10?Īs we know, Microsoft Office has a readymade function to password protect a document. To decode a file use: byte yourKey = generateKey("password") īyte decodedData = decodeFile(yourKey, bytesOfYourFile) įor reading in a file to a byte Array there a different way out there.In the previous tutorials we discussed the possible ways to lock a Word document (.doc/.docx) and encrypt an Excel workbook (.xls/.xlsx), and here we'll continue with the other widely used editor in Windows - Notepad. To save a encrypted file to sd do: File file = new File(Environment.getExternalStorageDirectory() + parator + "your_folder_on_sd", "file_name") īufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file)) īyte yourKey = generateKey("password") īyte filesBytes = encodeFile(yourKey, yourByteArra圜ontainigDataToEncrypt) Public static byte decodeFile(byte key, byte fileData) throws ExceptionĬipher.init(Cipher.DECRYPT_MODE, skeySpec) īyte decrypted = cipher.doFinal(fileData) SecretKeySpec skeySpec = new SecretKeySpec(key, "AES") Ĭipher cipher = Cipher.getInstance("AES") Ĭipher.init(Cipher.ENCRYPT_MODE, skeySpec) īyte encrypted = cipher.doFinal(fileData) Public static byte encodeFile(byte key, byte fileData) throws Exception SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto") KeyGenerator kgen = KeyGenerator.getInstance("AES") I had a similar problem and for encrypt/decrypt i came up with this solution: public static byte generateKey(String password) throws Exceptionīyte keyStart = password.getBytes("UTF-8")
This would make the streams incompatible and insecure for these kind of authenticated ciphers. Without an authentication tag the ciphertext may be changed in such a way that the change cannot be detected.īe warned that CipherInputStream may not report BadPaddingException, this includes BadPaddingException generated for authenticated ciphers such as GCM. To make it more secure, please add cryptographic integrity and authenticity by adding a secure checksum (MAC or HMAC) over the ciphertext and IV, preferably using a different key. In other words, don't use String.getBytes() but use String.getBytes(StandardCharsets.UTF_8).
Note that SHA-1 is a bit outdated hash function, but it should be fine in PBKDF2, and does currently present the most compatible option.Īlways specify the character encoding when encoding/decoding strings, or you'll be in trouble when the platform encoding differs from the previous one. PBKDF2 is the most commonly used Password Based Key Derivation scheme and it is present in most Java runtimes, including Android. If you want to use a password, please make sure you do use a good key derivation mechanism (look up password based encryption or password based key derivation). It is always exactly one block (16 bytes) in size. You can prefix the plain IV at the start of the ciphertext.
How to lock a folder in android without any app generator#
It should be present in any generic cryptographic library, ensuring high compatibility.ĭon't forget to use a Initialization Vector (IV) generated by a secure random generator if you want to encrypt multiple files with the same key. CBC mode is secure and does not have the vulnerabilities of ECB mode for non-random plaintexts. I would suggest something like Cipher.getInstance("AES/CBC/PKCS5Padding") for creating the Cipher class.
Use a CipherOutputStream or CipherInputStream with a Cipher and your FileInputStream / FileOutputStream.
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