Probably we will go in detail another time. However there is always a need for simple encryption and decryption process which we can easily incorporate in our code with out many dependency. While looking for such solution I came across this simple Blowfish implementation, which is very easy to understand and implement. Here is the most simple solution on how to easily encrypt and decrypt text in Java. Here is the decrypt method. This takes the encrypted text and the same key as the input. Thanks for this helpful information I agree with all points you have given to us.
Here is a StackOverflow implementation I liked. However Google Tink library has all this built in and you should take advantage of it. One important point to point out here is know that your android code is reverse engineerable and most cases most java code is too. That means if you store the password in plain text in your code.
A hacker can easily retrieve it. Usually, for these type of encryption, you want to use Asymmetric Cryptography and so on. This is outside the scope of this post so I will avoid diving into it. Once again I would suggest avoid implementing the java library for crypto directly and use Google Tink , it will save you the headache as they have really done a good job of implementing all the algorithms properly.
And even then make sure you check up on issues brought up on the Tink github, vulnerabilities popup here and there. If you have any questions or feedback feel free to comment! Security is always changing and you need to do your best to keep up with it :. While that is not the most secure algorithm, there are loads of implementations and you'd just need to give the key to anyone that is supposed to decrypt the information in the barcode. Cipher is what you want to work with here.
Next, you'll need the key and initialization vector bytes. The encryption mechanism in this post is a One-time pad, which means that the secret key can be easily recovered by an attacker using 2 encrypted messages. XOR 2 encrypted messages and you get the key. That simple! Jasypt can be easily used with well-known providers like Bouncy Castle.
Learn more. Binary encryption support. Jasypt allows the digest and encryption of binaries byte arrays. Encrypt your objects or files when needed for being sent over the net, for example.
Number encryption support. Besides texts and binaries, it allows the digest and encryption of numeric values BigInteger and BigDecimal, other numeric types are supported when encrypting for Hibernate persistence. Includes a lightweight "lite" version of the library for better manageability in size-restrictive environments like mobile platforms.
Provides both easy, no-configuration encryption tools for users new to encryption, and also highly configurable standard encryption tools, for power-users. Hibernate 3 and 4 optional integration for persisting fields of your mapped entities in an encrypted manner.
Encryption of fields is defined in the Hibernate mapping files, and it remains transparent for the rest of the application useful for sensitive personal data, databases with many read-enabled users Encrypt texts, binaries, numbers, booleans, dates Seamlessly integrable into a Spring application, with specific integration features for Spring 2, Spring 3.
All the digesters and encryptors in jasypt are designed to be easily used instantiated, dependency-injected And, because of their being thread-safe, they can be used without synchronization worries in a singleton-oriented environment like Spring. Learn more: Spring 2, Spring 3. Spring Security formerly Acegi Security optional integration for performing password encryption and matching tasks for the security framework, improving the security of your users' passwords by using safer password encryption mechanisms and providing you with a higher degree of configuration and control.
Provides advanced functionality for encrypting all or part of an application's configuration files, including sensitive information like database passwords. Comprehensive guides and javadoc documentation, to allow developers to better understand what they are really doing to their data.
Robust charset support, designed to adequately encrypt and digest texts whichever the original charset is. Complete support for languages like Japanese, Korean, Arabic Very high level of configuration capabilities: The developer can implement tricks like instructing an "encryptor" to ask a, for example, remote HTTPS server for the password to be used for encryption.
It lets you meet your security needs. The only requirement is that the IV has to be unique for each invocation with a given key.
If it repeats once for a given key, security can be compromised. An easy way to achieve this is to use a random IV from a strong pseudo random number generator as shown below. Using a sequence or timestamp as IV is also possible, but it may not be as trivial as it may sound. For example, if the system does not correctly keep track of the sequences already used as IV in a persistent store, an invocation may repeat an IV after a system reboot.
Likewise, there is no perfect clock. Computer clock readjusts etc. Hope someone would find this useful:. To encrypt a complete message, a mode needs to be selected. Authenticated encryption which provides both confidentiality and integrity is recommended. All these three modes are CTR-based counter-based modes and therefore they do not need padding. As a result they are not vulnerable to padding related attacks.
The IV is not a secret. The only requirement being it has to be random or unpredictable. In Java, the SecuredRandom class is meant to produce cryptographically strong pseudo random numbers. The pseudo-random number generation algorithm can be specified in the getInstance method. However, since Java 8, the recommended way is to use getInstanceStrong method which will use the strongest algorithm configured and provided by the Provider.
The recipient needs to know the IV to be able to decrypt the cipher text. Therefore the IV needs to be transferred along with the cipher text. However, that is not required. Strings should not be used to hold the clear text message or the key as Strings are immutable and thus we cannot clear them after use. These uncleared Strings then linger in the memory and may show up in a heap dump. For the same reason, the client calling these encryption or decryption methods should clear all the variables or arrays holding the message or the key after they are no longer needed.
Finally for transmission over network or storage, the key or the cipher text should be encoded using Base64 encoding. The details of Base64 can be found here. The Java 8 approach should be followed. However, as of Java 8, there is no easy way to clear SecretKeyspec and SecretKey as the implementations of these two interfaces do not seem to have implemented the method destroy of the interface Destroyable. In the following code, a separate method is written to clear the SecretKeySpec and SecretKey using reflection.
Note that keys are secrets like passwords, but unlike passwords which are meant for human use, keys are meant to be used by cryptographic algorithms and hence should be generated using the above way only. As pointed out by MaartenBodewes, my answer did not handle any String as is required by the question.
Therefore, I'll make an attempt to fill that gap just in case someone stumbles upon this answer and leaves wondering about handling String. As indicated earlier in the answer, handling sensitive information in a String is, in general, not a good idea because String is immutable and thus we cannot clear it off after use.
And as we know, even when a String doesn't have a strong reference, the garbage collector does not immediately rush to remove it off heap. Thus, the String continues to be around in the memory for an unknown window of time even though it is not accessible to the program. The issue with that is, a heap dump during that time frame would reveal the sensitive information. Therefore, it is always better to handle all sensitive information in a byte array or char array and then fill the array with 0s once their purpose is served.
However, with all that knowledge, if we still end up in a situation where the sensitive information to be encrypted is in a String , we first need to convert it into a byte array and invoke the encrypt and decrypt functions introduced above.
The other input key can be generated using the code snippet provided above. Here a simple solution with only java. It shall be indistinguishable under a choosen plaintext attack for short messages in the order of kilobytes.
This makes sure brute forcing passwords is hard and distributes the entropy over the entire key. A random initialisation vector IV is generated and will be prepended to the ciphertext. Furthermore, the static byte 0x01 is prepended as the first byte as a 'version'. Here it goes, zero external dependencies encryption class providing confidentiality and integrity :.
Edit: now with appropriate encryptString and decryptString. Here's my implementation from meta If you want to create a ciper instance for each call that would work also, and then you could remove the 'synchronized' calls, but beware 'cipher' is not thread-safe. The method name indicates the type of input string or byte array and the return type encoded string or byte array. The FirstChunk and LastChunk properties are used to indicate whether a chunk is the first, middle, or last in a stream to be encrypted.
By default, both FirstChunk and LastChunk equal true -- meaning that the data passed is the entire amount. Java Encryption Examples. I also recommend reading and voting for Konstantino's answer even though it doesn't provider any code.
The initialization vector IV is like a salt - it doesn't have to be kept secret. Use something like KeePass to generate a 32 character password. This solution is modeled after my Ruby solution. It can generate different encryption and decryption code each time for the string or file encryption. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. How to encrypt String in Java Ask Question.
Asked 12 years, 5 months ago. Active 2 years, 1 month ago. Viewed k times. Improve this question. Andrii Abramov 8, 8 8 gold badges 62 62 silver badges 85 85 bronze badges. Visit: software-architect. Code example: Decryption import java. The translation of data into a secret code. Encryption is the most effective way to achieve data security. To read an encrypted file, you must have access to a secret key or password that enables you to decrypt it.
Unencrypted data is called plain text ; encrypted data is referred to as cipher text. Examples which use IVs are ciphers in feedback mode, e. Step 2: Select the cipher you want to use, then type in a password. In cryptography , a salt is random data that is used as an additional input to a one-way function that hashes data, a password or passphrase. Salts are used to safeguard passwords in storage.
Salts defend against a pre-computed hash attack. Symmetric encryption is an encryption methodology that uses a single key to encrypt encode and decrypt decode data. There are five main components of a symmetric encryption system: Plaintext, encryption algorithm, secret key, ciphertext, and the decryption algorithm. A block cipher is an algorithm that encrypts data on a per-block basis. The size of each block is usually measured in bits.
AES , for example , is bits long. Meaning, AES will operate on bits of plaintext to produce bits of ciphertext. PKCS5Padding schema is actually very simple. It follows the following rules: The number of bytes to be padded equals to "8 - numberOfBytes clearText mod 8". Encryption works by taking plain text and converting it into cipher text, which is made up of seemingly random characters.
Only those who have the special key can decrypt it. AES uses symmetric key encryption , which involves the use of only one secret key to cipher and decipher information. This type of encryption uses a single key known as private key or secret key to encrypt and decrypt sensitive information.
This type of encryption is very fast as compared to asymmetric encryption and are used in systems such as database system. Understanding AES Encryption. Encryption is fundamental to contemporary internet security.
Originally adopted by the federal government, AES encryption has become the industry standard for data security. Main issue with DES was the short encryption key size.
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