How to encrypt string with AES?

The Advanced Encryption Standard is the most commonly used encryption algorithm in use on computers and over the internet. To encrypt a string, select the green Encrypt button, enter the text you want to encrypt in the upper Plaintext box, and enter the key or password that it should be encrypted with in the Key box .

Can I decrypt AES without a key?

If its encrypted, the only way to get the contents without the encryption key is to brute-force it , but I wouldn't get your hopes up. All these malware variants as of late rely on encryption being nearly unbreakable without government-funded super computing power, and even then its time consuming.

How to decrypt an AES encrypted password?

You decrypt using the same key as used for AES encryption . AES is a symmetric block cipher after all: both the “sender” and “receiver” need to use the same key. Guessing the AES key is next to impossible unless you know the data used to generate it in the first place. Note that AES in itself is not a secure cipher.

How to decrypt an encrypted string?

Decryption Approach: Find the length L of the string. Find the ceil and floor values of ? Length and assign them to the variables. Create a 2D matrix and fill the matrix by characters of string column-wise. Read the matrix row-wise to get the decrypted string. Dec 27, 2022

What is the difference between AES and AES string?

Furthermore it is said that aes uses non-standard evaluation to capture the variable names. whereas aes_string uses regular evaluation . Non-standard evaluation is described by Hadley Wickham in his book Advanced R as a method to not only call the values of a functions argument but also the code that produced them.

How would you encrypt any given string?

Encrypting and Decrypting a String Generate a Symmetric Key. Create a Context for Encryption. Open the Destination File Stream. Create the Encryption Stream. Open the Encode Stream. Define the Archive Header. Write the String to the Encode Stream. Open the Source File Stream. More items...

How do I encrypt a text file in AES?

Choose a key size (128, 192, or 256 bits) and a mode of operation (such as CBC or CTR). Generate a random key. Pad the input file to a multiple of the block size (128 bits). Divide the input file into blocks and encrypt each block with AES using the key and mode of operation selected in step 1. More items... Feb 15, 2023

How to AES encrypt a string in Java?

The encrypt() method takes three parameters: the string to encrypt, a secret key, and a salt . A random Initialization Vector (IV) is generated for each encryption. The provided secret key and salt are used to derive an encryption key using PBKDF2 with SHA-256. The secret key is created and used for AES encryption.

Can AES be used for encryption?

The Advanced Encryption Standard (AES) is a symmetric block cipher chosen by the U.S. government to protect classified information. AES is implemented in software and hardware throughout the world to encrypt sensitive data .

String Encryption - PreEmptive Protection DashO 12.3 (2024)

String Encryption is the process by which PreEmptive Protection™ DashO™ replaces strings in the constant pools of processed classes with encrypted values that are then decrypted in the running application, making it more difficult to read the string constants via static analysis of the code.This both offers a layer of protection to sensitive strings and otherwise makes it more difficult to understand the software.For instance, with String Encryption an attacker cannot easily locate the string constant for a specific message to find where it is used.

You can enable/disable and configure String Encryption on the String Encryption - Options page of the DashO GUI.

Page Contents

Use Removal With String Encryption
String Encryption and Reflection in Android Mode
Configuration

String Encryption Level
Number of Decrypters
Intern Strings
Decrypter Classes
String Encryption Map Files
Includes and Excludes
Custom Encryption

Use Removal With String Encryption

String Encryption alone protects most strings, but inlined string constants are not always fully protected.The Java compiler inlines string constants, effectively copying them into the places where they are used.DashO does not encrypt the original field values, because this could produce incorrect behavior, e.g. breaking the value of a library API constant that is used by an external application.

This means that some string constants will remain in place, unencrypted, after String Encryption.If these string constants will not be used by external applications then they can be safely removed.Therefore, to protect those string constants, configure DashO to remove unused members.Inlined string constant references will not mark the defining field as "used".

For libraries, specify Remove if not public; otherwise specify Remove.When using Remove if not public, public strings (those having "public" or "protected" modifiers) will not be removed, so any strings that require protection should not be public.The effect of these settings can be adjusted by excluding classes, methods, or fields from Removal.

String Encryption and Reflection in Android Mode

In Android Mode, Renaming and Removal are handled by R8, while String Encryption is handled by DashO.On its own, R8 is able to detect some classes accessed via reflection and exclude them from Renaming and Removal.

However, DashO's String Encryption can prevent R8 from recognizing class names in String literals. This can cause R8 to remove or rename classes loaded via reflection, causing errors at runtime.To prevent these errors, either:

Add R8 -keep rules to prevent the classes that are loaded via reflection from being removed or renamed, or:
Exclude methods that contain reflection calls from String Encryption so that R8 can detect classes loaded by these calls.You can also use -adaptclassstrings with R8 to allow R8 to rename these classes and update String literals accordingly.

Configuration

You can configure the following settings on the String Encryption - Options page of the DashO GUI.

Note:If you configure string encryption include/exclude rules at the method-level, in some cases strings reused by methods with different rules may not be encrypted as expected.

String Encryption Level

The String Encryption Level, on a scale from 1 to 10, controls the strength and performance of the encryption and decryption algorithms.A higher level will have stronger encryption but will take longer at runtime to decrypt, potentially slowing down the application.The default level is "2".

Number of Decrypters

You can control the number of decrypters that will be generated and added to classes included in each output.The names and signatures of the methods are randomly selected (except when using an input map file).The default number of decrypters is "2".

Notes:
For unmerged outputs, the number of decrypters created will be multiplied by number of inputs.
If you want decrypters to be placed globally (not kept internal to the jars where they are used) add a User Property named INJECT_DECRYPTERS_GLOBALLY and set it to true.
If this property is set, the configured number of decrypters will divided among the outputs, not added to each output.
Decrypters are always placed globally in Android Mode.

Intern Strings

Controls whether intern() should be called on strings before returning them from the injected string decrypter.The intern() method makes sure that equal strings are only represented once in memory.

Note:If Intern Strings is turned off, any protected code, including library code, that uses == for string comparison may return false when comparing values from equal strings.You should always use .equals() instead of == when comparing strings.

Decrypter Classes

You can control to which classes may serve as outer classes for the generated anonymous static inner classes that will house the decrypters.You can specify the following criteria for these classes:

Packages that these classes must not be chosen from
Modifiers such as public that these classes must match
A regular expression, glob pattern, or name that the class's name must match

By default, DashO will exclude all java., javax., and android. packages and will only include public classes.

Note: If you specify name criteria, the decrypters will be injected based on that criteria and will be used without regards to jar boundaries.

String Encryption Map Files

If you are using Incremental Obfuscation, it is important that DashO is capable of reproducing the decrypters used when the initial obfuscation took place.Otherwise, the new obfuscated code may not interoperate properly with previously obfuscated code.A String Encryption Map File is used to document which decrypters were placed and where they were placed in a previous run of DashO.

On the String Encryption - Options page of the DashO GUI you can specify both a location of an input map file and a location for an output map file.If an output map file location is specified, then DashO will produce a String Encryption map file containing information about the decrypters produced during that build.If an input map file is specified, then DashO will reproduce the string decrypters described in the map file, and will ignore settings for the String Encryption Level and the Number of Decrypters.

Note:String Encryption Map Files are not supported in Android Mode.

Includes and Excludes

You can set rules to determine where String Encryption is applied.String Encryption has a cost in terms of size and runtime performance, so you may want to apply it only to more sensitive parts of your application.You can specify String Encryption Includes and Excludes on the String Encryption - Include and String Encryption - Exclude pages of the DashO GUI.If no includes are specified, DashO will apply String Encryption to all methods not covered by an exclude rule.If any include rules are defined, then DashO will apply String Encryption only to included methods.

Custom Encryption

You can specify custom encryption and decryption methods for DashO to use in place of its default String Encryption.See Custom Encryption for details.