How to encrypt data with AES-256 in UE4

In this short tip, I will show you how to encrypt data with AES-256 in UE4.

The code will be written in C++ but can be used later in blueprints.

First thing what you need to do is to create a class, derived from UBlueprintFunctionLibrary.

Then add two methods to the header:

UFUNCTION(BlueprintCallable, Category = "AES256")
static FString Encrypt(FString InputString, FString Key);

UFUNCTION(BlueprintCallable, Category = "AES256")
static FString Decrypt(FString InputString, FString Key);

After that implement those methods:

FString UChangeToYourBlueprintFunctionLibraryName::Encrypt(FString InputString, FString Key)
{
	// Check inputs
	if (InputString.IsEmpty()) return "";  //empty string? do nothing
	if (Key.IsEmpty()) return "";

	// To split correctly final result of decryption from trash symbols
	FString SplitSymbol = "EL@$@!";
	InputString.Append(SplitSymbol);

	// We need at least 32 symbols key
	Key = FMD5::HashAnsiString(*Key);
	TCHAR *KeyTChar = Key.GetCharArray().GetData();           
	ANSICHAR *KeyAnsi = (ANSICHAR*)TCHAR_TO_ANSI(KeyTChar);

	// Calculate blob size and create blob
	uint8* Blob; 
	uint32 Size; 
	 
	Size = InputString.Len();
	Size = Size + (FAES::AESBlockSize - (Size % FAES::AESBlockSize));

	Blob = new uint8[Size];

	// Convert string to bytes and encrypt
	if(StringToBytes(InputString, Blob, Size)) {

		FAES::EncryptData(Blob, Size, KeyAnsi);
		InputString = FString::FromHexBlob(Blob, Size);

		delete Blob;
		return InputString;		
	}

	delete Blob;
	return ""; 
}

FString UChangeToYourBlueprintFunctionLibraryName::Decrypt(FString InputString, FString Key)
{
	// Check inputs
	if (InputString.IsEmpty()) return ""; 
	if (Key.IsEmpty()) return "";

	// To split correctly final result of decryption from trash symbols
	FString SplitSymbol = "EL@$@!";

	// We need at least 32 symbols key
	Key = FMD5::HashAnsiString(*Key);
	TCHAR *KeyTChar = Key.GetCharArray().GetData();
	ANSICHAR *KeyAnsi = (ANSICHAR*)TCHAR_TO_ANSI(KeyTChar);
	
	// Calculate blob size and create blob
	uint8* Blob; 
	uint32 Size; 

	Size = InputString.Len();
	Size = Size + (FAES::AESBlockSize - (Size % FAES::AESBlockSize));

	Blob = new uint8[Size]; 

	// Convert string to bytes and decrypt
	if (FString::ToHexBlob(InputString, Blob, Size)) {

		FAES::DecryptData(Blob, Size, KeyAnsi);		
		InputString = BytesToString(Blob, Size);

		// Split required data from trash
		FString LeftData;	
		FString RightData;	
		InputString.Split(SplitSymbol, &LeftData, &RightData, ESearchCase::CaseSensitive, ESearchDir::FromStart);
		InputString = LeftData;

		delete Blob; 
		return InputString; 
	}

	delete Blob; 
	return ""; 
}

Don’t forget to add proper include headers:

#include "Runtime/Core/Public/Misc/AES.h"
#include "Runtime/Core/Public/Misc/SecureHash.h"
#include "Runtime/Core/Public/Misc/Base64.h"

Next, compile the project and that’s all. You can use those methods to encrypt/decrypt strings with the specified password. It’s possible to adapt those methods to work with other input parameters (like custom structs, bytes or integers).