I'm student and doing research work about Advanced Encryption Standard (AES).
I choose AES-256 CBC. I'm trying to encrypt text files with threads (1 thread - 1 file)
Encryption is OK, but decryption has problem. When I try to decrypt file, it has undecrypted strings. I read some documents about AES and found that AES CBC has no opportunity to encrypt files multithreaded because of initialization vector (IV), it's unic for each file.
Can I convert AES-CBC to multithreaded class?
Related
I want to make Salsa20 Text Encryption using C++
I took this source code as main
How to initialize iv and key? How to encrypt bytes?
I need to create a internal AES/Base64 encrypt system for my application.
I mean , I don't want to have any side dll for my exe like openssl library.
I found this threads :
Problems with CryptoPP C++ AES-256+Base64
Crypto++ encrypt and decrypt in two different c++ programs
But they wasn't what I need , I searched and I found nothing.
What I need exactly is like this site : https://aesencryption.net/
First an AES encryption with a key at 256bit mode
Next convert it to Base64 ( a Result of encryption in base64 in aesencryption.net )
And a decrypt system to get the first string from encrypted result.
In this thread the key has to be 32 lenght but in the aesencryption.net it can be everything .
Can you please guide me how can I create a system like aesencryption.net site ?
So I am using the Crypto++ Library to encrypt a file. I need to save the key and iv for future use. I am following this tutorial. Here is my function :
void AESUtil::encrypt(string filename,bool savekeys,string savefilename){
AutoSeededRandomPool rnd;
// Generate a random key
byte key[AES::DEFAULT_KEYLENGTH];
rnd.GenerateBlock(key, AES::DEFAULT_KEYLENGTH);
// Generate a random IV
byte iv[AES::BLOCKSIZE];
rnd.GenerateBlock(iv, AES::BLOCKSIZE);
Binary b;
string plaintext = b.decoder(filename);
unsigned char *ciphertext= new unsigned char[plaintext.size()+1];
ciphertext[plaintext.size()]='\0';
if(savekeys){
ofstream("key.bin", ios::binary).write((char*)key, sizeof(key));
}
CFB_Mode<AES>::Encryption cfbEncryption(key, AES::DEFAULT_KEYLENGTH, iv);
cfbEncryption.ProcessData(ciphertext,reinterpret_cast<const unsigned char*>(plaintext.c_str()),plaintext.size()+1);
ofstream outfile(savefilename.c_str());
outfile.write((char*)ciphertext,sizeof(ciphertext));
}
The files contain data in �/���� format. I want to know the best method to save the key and iv programmatically which are a byte array to a file and the ciphertext which is a unsigned char* to a separate file.
The key could be saved in a separate file. Normally the key is established between sender / receiver in advance, or it is encrypted using a public key of the receiver. Note that it doesn't make sense to save the key next to the ciphertext, as it would provide no protection whatsoever. The handling of keys is called key management and entire books have been written about it.
The IV is a different animal. The IV should be randomly generated. For CFB it should at least be unique and identical at both sides. Usually the IV is simply prefixed to the ciphertext, it doesn't have to be kept secret.
Your key and iv variables are the key and IV used to encrypt the plain text.
You didn't fill either; you're actually using an array filled with 0 bytes as both the key and IV for your encryption.
The IV is public information. You don't need to hide it. Save it the way you want.
The KEY is what you must keep safe. To do that you may decide how much effort you want to put on it to hide it from the external factors.
I have some keys that I don't care to leave them as a "plain text" in the binary code. (NO SECURITY, but my mom can't figure out what to do, but a beginner in reverse engineer will laugh at it.)
Some keys I do a play with the bytes, like inverting parts, separating them, XOR with something. (Very unsafe, but better than nothing, a programmer with decent knowledge in reverse engineering will be able to spend some time and eventually break the security)
Some other cases I use 3rd party advanced obfuscation... If possible, depending on what you want, you may even replace your encryption engine with some "white-box" cryptography. Then you will have your keys very well protected. But this is usually hard/expensive. It doesn't seem to be your case. (Yes, even a very advanced assembly guru will not be happy to start reverse engineer this case.)
Another solution, if you don't need the key on your binary, is to give it to the system's password manager. On Windows, it's called "Data Protection API", and on Mac, it's called "Keychain". Take a look at these, and then you will understand why this is considered security. But it's because all the passwords here are encrypted with the "user password" so nothing is stored "on disk". A turned-off device in this scenario is considered very secure.
When using Botan encryption with botansqlite3, what are the optimal configuration settings for performance?
OR
How can I configure Botansqlite3 to use CAST5?
I am currently using AES and it is too slow. My use case is a game.
I am looking for weak or moderate encryption to protect my game's data (not end user data) so security is less of a consideration than performance.
Here is my current BotanSqlite3 codec.h
/*These constants can be used to tweak the codec behavior as follows */
//BLOCK_CIPHER_STR: Cipher and mode used for encrypting the database
//make sure to add "/NoPadding" for modes that use padding schemes
const string BLOCK_CIPHER_STR = "Twofish/XTS";
//PBKDF_STR: Key derivation function used to derive both the encryption
//and IV derivation keys from the given database passphrase
const string PBKDF_STR = "PBKDF2(SHA-160)";
//SALT_STR: Hard coded salt used to derive the key from the passphrase.
const string SALT_STR = "&g#nB'9]";
//SALT_SIZE: Size of the salt in bytes (as given in SALT_STR)
const int SALT_SIZE = 64/8; //64 bit, 8 byte salt
//MAC_STR: CMAC used to derive the IV that is used for db page
//encryption
const string MAC_STR = "CMAC(Twofish)";
//PBKDF_ITERATIONS: Number of hash iterations used in the key derivation
//process.
const int PBKDF_ITERATIONS = 10000;
//KEY_SIZE: Size of the encryption key. Note that XTS splits the key
//between two ciphers, so if you're using XTS, double the intended key
//size. (ie, "AES-128/XTS" should have a 256 bit KEY_SIZE)
const int KEY_SIZE = 512/8; //512 bit, 64 byte key. (256 bit XTS key)
//IV_DERIVATION_KEY_SIZE: Size of the key used with the CMAC (MAC_STR)
//above.
const int IV_DERIVATION_KEY_SIZE = 256/8; //256 bit, 32 byte key
//This is definited in sqlite.h and very unlikely to change
#define SQLITE_MAX_PAGE_SIZE 32768
I believe that I need to find replacements for BLOCK_CIPHER_STR, PBKDF_STR, MAC_STR, KEY_SIZE and IV_DERIVATION_KEY_SIZE to reconfigure BotanSqlite3 to use a different codec.
I found a extensive comparison test of Botan codec performance here:
http://panthema.net/2008/0714-cryptography-speedtest-comparison/crypto-speedtest-0.1/results/cpu-sidebyside-comparison-3x2.pdf#page=5
However, the testing was done with Botan directly, not botansqlite3 as I intend to use it. Looking at the charts, a good candidate appears to be CAST5 from a performance perspective.
The database in question is 300KB, mostly INTEGER fields with some text blobs.
I am configuring Botan as suggested by OlivierJG of botansqlite3 fame, using the amalgamation
'./configure.py --no-autoload --enable-modules=twofish,xts,pbkdf2,cmac,sha1 --gen-amalgamation --cc=msvc --os=win32 --cpu=x86 --disable-shared --disable-asm'
References:
http://github.com/OlivierJG/botansqlite3 - botansqlite3 is an encryption codec for SQLite3 that can use any algorithms in Botan for encryption
http://www.sqlite.org - sqlite3 is a cross-platform SQL database
http://botan.randombit.net/ - botan is a C++ encryption library with support for a number of codecs
You can get CAST-128 (or as I was calling it, CAST5) to work, it is a block cipher.
The best bet is the above with different configuration of key size.
Twofish is pretty fast.
Thank you to 'Olivier JG' for all the excellent code.
I have a message coming from an external company which has been encrypted with our public key using Java.
Specifically the java code performing the encryption is -
//get instance of cipher using BouncyCastle cryptography provider
Cipher cipher = Cipher.getInstance( "RSA/ECB/PKCS1Padding", "BC");
//initialize the cipher with the public key pulled from the X509 certificate
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
I need to be able to decrypt this message using our private key using C/C++ on Solaris.
I have tried using the Crypto++ library and can successfully encode decode messages just using Crypto++, but am unable to work out how to decode the message encrypted from the java side.
Specifically I tried using a RSAES_PKCS1v15_Decryptor but this does not seem to work.
Does anyone have any suggestions as to how I can perform the decryption such as
The required Crypto++ code (ideal)
Alternatives to RSA/ECB/PKCS1Padding to use from the Java side
Alternative open source C libraries I could try
Anything else...
I managed to get this working by changing the java code to use
Cipher cipher = Cipher.getInstance( "RSA/NONE/PKCS1Padding", "BC");
This then matches up with RSAES_PKCS1v15_Decryptor on the Crypto++ side.