qt openssl AES decrypting what already encrypted problem

[Proton Phoenix]

Hi ~~ I Have a problem ... if i encrypt a data then directly decrypt it ... it works and i get the result i want ...
but if i get a base64 aes256 encrypted message then trying to decrypt the same message it won't work ... even with the same password
i knew it's salt or IV problem ... but how can i fix those functions and many thanks <3

QByteArray Cipher::encrypt(const QByteArray &data, const QByteArray &password)
{

    int outLen=0;
    QByteArray dataBuff;dataBuff.resize(data.size()+AES_BLOCK_SIZE);
    EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
    EVP_CIPHER_CTX_init(ctx);

    EVP_CIPHER_CTX_init(ctx);
    if(!EVP_EncryptInit(ctx,EVP_aes_256_cbc(),(const unsigned char*)sha256(password).data(),(const unsigned char*)sha256("tryingAES"+password).data())){
        qCritical() << "EVP_EncryptInit_ex() failed " << ERR_error_string(ERR_get_error(), NULL);

        return QByteArray();
    }
    if(!EVP_EncryptUpdate(ctx,(unsigned char*)dataBuff.data(),&outLen,(const unsigned char*)data.data(),data.size())){
        qCritical() << "EVP_EncryptUpdate() failed " << ERR_error_string(ERR_get_error(), NULL);
        return QByteArray();
    }
    int tempLen=outLen;
    if(!EVP_EncryptFinal(ctx,(unsigned char*)dataBuff.data()+tempLen,&outLen)){
        qCritical() << "EVP_EncryptFinal_ex() failed "  << ERR_error_string(ERR_get_error(), NULL);
        return QByteArray();
    }
    tempLen+=outLen;
    EVP_CIPHER_CTX_cleanup(ctx);
    dataBuff.resize(tempLen);
    return dataBuff;

    EVP_CIPHER_CTX_free(ctx);

}

^^

QByteArray Cipher::decrypt(const QByteArray &data, const QByteArray &password)
{
    int outLen=0;
    QByteArray dataBuff;dataBuff.resize(data.size()+AES_BLOCK_SIZE);
    EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
    EVP_CIPHER_CTX_init(ctx);
    EVP_DecryptInit(ctx,EVP_aes_256_cbc(),(const unsigned char*)sha256(password).data(),(const unsigned char*)sha256("tryingAES"+password).data());
    EVP_DecryptUpdate(ctx,(unsigned char*)dataBuff.data(),&outLen,(const unsigned char*)data.data(),data.size());
    int tempLen=outLen;
    EVP_DecryptFinal(ctx,(unsigned char*)dataBuff.data()+tempLen,&outLen);
    tempLen+=outLen;
    EVP_CIPHER_CTX_cleanup(ctx);
    dataBuff.resize(tempLen);
    return dataBuff;
}

^^
QByteArray Cipher::sha256(const QByteArray &text)
{
        unsigned int outLen=0;
        QByteArray dataBuff; dataBuff.resize(EVP_MAX_MD_SIZE);

        EVP_MD_CTX *evpMdCtx=EVP_MD_CTX_new();
        EVP_DigestInit(evpMdCtx, EVP_sha256());
        EVP_DigestUpdate(evpMdCtx, text.data(), text.size());
        EVP_DigestFinal_ex(evpMdCtx, (unsigned char *)dataBuff.data(), &outLen);

        dataBuff.resize(outLen);
        qDebug()<<"databuffer"<<dataBuff.toHex();
       //   EVP_MD_CTX_cleanup(evpMdCtx);

        return dataBuff;
}

and this is the calling function ..

Cipher wrapper;
  QByteArray pass="passwordtrying";
  QByteArray data =ui->encrypttextedit->toPlainText().toUtf8();

  QByteArray decrypt=wrapper.decrypt(data,pass);
  ui->decrypttextedit->setText(decrypt);

The Result Should be a MAC ADDRESS like : E3:53:24:H3 ... Just As example
decrypting works only if i encrypt and decrypt in the same function .. but i want to decrypt what already encrypted from the software

[hskoglund]

Hi, I don't see any key and initialization vector computation, it's done with the EVP_BytesToKey() function, for more see here

Two calls to EVP_CIPHER_CTX_Init is correct but you need two different contexts I think not the same context twice :-(

...
 EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
 EVP_CIPHER_CTX_init(ctx);

 EVP_CIPHER_CTX_init(ctx);
...

AES is more than 20 years old so there are lots of examples out there, I wrote a Qt demo console app couple of years ago in the forum

[hskoglund]

Hi, that base64-encoded string that begins with "GFdws...." does not look like valid base64, because the length must be a multiple of 4, and it looks like it's 38 characters :-(

[Proton Phoenix]

This post is deleted!

[Proton Phoenix]

@hskoglund Thank you bro i just modified it for privacy reasons just a moment i will edit the topic

~~ Now i encrypted just example mac E4:5C:2F:1A:43

if i encrypt it and decrypt it in the same function it decrypt it successfully but if i try to decrypt what already encrypted ... it doesn't

[hskoglund]

Hi, I don't see any key and initialization vector computation, it's done with the EVP_BytesToKey() function, for more see here

Two calls to EVP_CIPHER_CTX_Init is correct but you need two different contexts I think not the same context twice :-(

...
 EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
 EVP_CIPHER_CTX_init(ctx);

 EVP_CIPHER_CTX_init(ctx);
...

AES is more than 20 years old so there are lots of examples out there, I wrote a Qt demo console app couple of years ago in the forum

[Proton Phoenix]

Really Thank you bro <3 you helped me a lot ... for me i was trying to get some examples from github i didn't look so much in openssl documentation a
thank you the idea now is very clear because of your help
i wish happy life for you bro <3 many thanks