[Qt-interest] QCA big string encryption

[Nicholas Shatokhin]

If I'm not make mistake, it's synchronous alhorithm. But I need  
asynchronous (RSA). I got code there  
http://delta.affinix.com/docs/qca/rsatest_8cpp-example.html but code in  
this example can't  encode more than key's length. And I don't see any  
finalize there :(

Sun, 24 Apr 2011 22:29:31 +0300 було написано Jason H <scorp1us at yahoo.com>:

> http://delta.affinix.com/docs/qca/ciphertest_8cpp-example.html#_a7 shows
> everything you need to know.
> process() is the convince function which combines update() with  
> finalize()
>
>
>
>
>
>
> ----- Original Message ----
> From: Nicholas Shatokhin <n.shatokhin at gmail.com>
> To: qt-interest at qt.nokia.com; Jason H <scorp1us at yahoo.com>
> Sent: Sun, April 24, 2011 3:11:56 PM
> Subject: Re: [Qt-interest] QCA big string encryption
>
> What class contain method finalize?
> How can I realize encode/decode by RSA with QCA?
>
> Sun, 24 Apr 2011 22:06:22 +0300 було написано Jason H  
> <scorp1us at yahoo.com>:
>
>> Generally you need an IV (Initialization vector) this then is fed to the
>> routines with the keys. The IV is an important random number so that if  
>> you
> can
>> encrypt the same message with the same keys multiple times and not get  
>> the
> same
>> encrypted message (thus ruling out a dictionary attack)
>>
>> Anyway, there are two types of cyphers, block and stream. With block  
>> cyphers,
>> you work a block at a time. The last block will usually be incomplete,  
>> and
>> there
>> is some final[ize[() method for handling this special block. Normally,  
>> the
>> enc/decrypt functions in QCA will give you all complete blocks, leaving  
>> you to
>> call finalize().
>>
>> QCA does have convince functions that will do it all without you having  
>> to
> call
>> finalize(), HOWEVER this should only be used for messages of known,  
>> short
>> lengths. The non-convenience functions are designed to be used in a  
>> streaming
>> manner, which is better for memory and scalability.
>>
>>
>>
>> HTH, but AFAIAC, this is a QCA question, not a Qt question.
>>
>>
>>
>>
>> ----- Original Message ----
>> From: Nicholas Shatokhin <n.shatokhin at gmail.com>
>> To: qt-interest at qt.nokia.com; Jason H <scorp1us at yahoo.com>
>> Sent: Sun, April 24, 2011 2:52:53 PM
>> Subject: Re: [Qt-interest] QCA big string encryption
>>
>> What do you mean?
>>
>> There is my code below. What must I add? (I use 1024bit rsa key and  
>> message
>> truncate to 1024bit)
>>
>>
>> bool CCryptor::generateKeys(int size)
>> {
>>     if(init())
>>     {
>>         QCA::PrivateKey seckey = QCA::KeyGenerator().createRSA(size);
>>
>>         if(seckey.isNull())
>>         {
>>             std::cout << "Failed to make private RSA key" << std::endl;
>>             return false;
>>         }
>>
>>         QCA::PublicKey pubkey = seckey.toPublicKey();
>>
>>         privateKey = seckey;
>>         publicKey = pubkey;
>>
>>         return true;
>>     }
>>     else
>>         return false;
>> }
>>
>> QByteArray CCryptor::dataEnrypt(QByteArray data)
>> {
>>     // check if the key can encrypt
>>     if(!publicKey.canEncrypt())
>>     {
>>         std::cout << "Error: this kind of key cannot encrypt" <<  
>> std::endl;
>>         return QByteArray();
>>     }
>>
>>     QCA::SecureArray arg = data;
>>
>>     // encrypt some data - note that only the public key is required
>>     // you must also choose the algorithm to be used
>>     QCA::SecureArray result = publicKey.encrypt(arg,  
>> QCA::EME_PKCS1_OAEP);
>>
>>     if(result.isEmpty()) {
>>         std::cout << "Error encrypting" << std::endl;
>>         return QByteArray();
>>     }
>>
>>     return result.toByteArray();
>> }
>>
>> QByteArray CCryptor::dataDecrypt(QByteArray data)
>> {
>>     QCA::SecureArray encrypt = data;
>>     QCA::SecureArray decrypt;
>>     if(0 == privateKey.decrypt(encrypt, &decrypt, QCA::EME_PKCS1_OAEP))
>>     {
>>         std::cout << "Error decrypting.\n";
>>         return QByteArray();
>>     }
>>
>>     return decrypt.data();
>> }
>>
>>
>>
>> Sun, 24 Apr 2011 21:31:38 +0300 було написано Jason H  
>> <scorp1us at yahoo.com>:
>>
>>> It's beena  while since I used QCA, but do you need to finalize() it  
>>> for the
>>> last block?
>>>
>>>
>>>
>>>
>>> ----- Original Message ----
>>> From: Nicholas Shatokhin <n.shatokhin at gmail.com>
>>> To: qt-interest at qt.nokia.com
>>> Sent: Sun, April 24, 2011 1:12:41 PM
>>> Subject: [Qt-interest] QCA big string encryption
>>>
>>> Hello.
>>>
>>> I'm trying to encrypt end decrypt long string. But after decryption, I  
>>> get
>>> only part of string. What's wrong?
>>>
>>> Code:
>>>
>>>      QCA::SecureArray arg = data;
>>>      qDebug() << arg.toByteArray();
>>>      QCA::SecureArray result = publicKey.encrypt(arg,  
>>> QCA::EME_PKCS1_OAEP);
>>>      privateKey.decrypt(result, &arg, QCA::EME_PKCS1_OAEP);
>>>      qDebug() << arg.toByteArray();
>>>
>>> Output:
>>>
>>> "{"method": 1, "data": {"email": "dfgh", "usePassword": "false",
>>> "password": "", "useFingerprint": false, "fingerprint": "",  
>>> "publicKey":
>>> "LS0tLS1CRUdJTiBQVUJMSUMgS0VZLS0tLS0KTUlHZk1BMEdDU3FHU0liM0RRRUJBUVVBQTRHTkFEQ0JpUUtCZ1FDN05UNjd6R1pHajZpbDc5K3ErOWo5K2s5cApnVHJJOGxRVlFoQkxuVWxBNFArS01selBEOU9aOEk0UXRWNEdjT0ZOYWFyTjByZFlacllKaVF2VjBUQkdSSnRWCnNEOTVsZzNPMHFzVHBuSVdrYW5rUTVFUmdiTDlqQ0grb0taNFBrUEd0OW9MVjhCOGphNjFRazdhLytBVUZ1UUQKeDBMUGZvUyt5VkVoYXNjM0x3SURBUUFCCi0tLS0tRU5EIFBVQkxJQyBLRVktLS0tLQo="}
>>> }
>>> }
>>> }"
>>>
>>> "{"method": 1, "data": {"email": "dfgh", "usePassword": "false",
>>> "password": "", "useFi"
>>>
>>>
>>> Best regards,
>>> Nick.
>>>
>>
>>
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>>
>
>
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