Is there a way to make output from QCryptographicHash readable QByteArray?
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wrote on 17 Jun 2021, 16:44 last edited by artwaw
Good afternoon.
I spent half of the afternoon trying to find a solution and I must be dumb or not know something.The task:
internally I use this one-liner to create hashed passwords:python -c "from passlib.hash import sha512_crypt; import getpass,string,random; print(sha512_crypt.using(salt=''.join([random.choice(string.ascii_letters + string.digits) for _ in range(16)]),rounds=5000).hash(getpass.getpass()))"
but recently I had a need to ask non-technical people to do the same, so I can deal only with hashes and not their passwords. Since it is not urgent I decided to play a bit and came out with this code (compilable excerpts).
MethodgenerateRndStr()
returns QString and does generate random string from the pool of allowed characters and desired length passed as a parameter.
Method crypt is fromunistd.h
QByteArray CryptoClass::getHash(const QByteArray &data) const { QCryptographicHash *hash = new QCryptograhicHash(QCryptographicHash::Sha512); hash->addData(crypt(data.constData(),generateRndStr(16).toUtf8().constData())); return hash->result();
crypt() expects
const char *
as parameters so QByteArray::constData() seems to be ok? It returnschar *
so I assume it is compatible with QByteArray (I also checked printing raw values to stdout: salt, password and result ofcrypt()
are as to be expected, all printable chars.At any rate, when I wanted to compare the output from the python one-liner and my routine I run into trouble - how the hell do I convert this to text? I tried QString but that got me only running in circles and garbage on the screen. Same with printf to the stdout.
What do I miss here? Or is my approach somehow wrong?EDIT: example output from the python one-liner and where do I want to get to:
$6$Lt5bExFakB7nrZEN$3KHS5HLNe8UwSxGQY6foF3vJiv/VxiGi2WWvz04c4OpoXgIB37GeaF6ILFtGhHZSMA7hL/6nGmEHeRRADXXWQ1
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@Christian-Ehrlicher my bad but this is inly excerpt. In the program it is a member and is deleted in the destructor.
And it is on the heap since I don't know how to initialise it otherwise (method selection). One of the constrains I face is that it has to be SHA-512 and only that.So you say QByteArray::toBase64 should suffice?
@mrjj I examined and tested the code from which excerpts are here, worked over 100 times both in loop with no wait and waiting for user input.
@artwaw said in Is there a way to make output from QCryptographicHash readable QByteArray?:
And it is on the heap since I don't know how to initialise it otherwise (method selection).
I don't understand this? Why does
QCryptographicHash hash(QCryptographicHash::Sha512);
not work?
So you say QByteArray::toBase64 should suffice?
Yes
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Lifetime Qt Championwrote on 17 Jun 2021, 16:57 last edited by Christian Ehrlicher
Hashes are normally printed as base64 and so it's
$6$Lt5bExFakB7nrZEN$3KHS5HLNe8UwSxGQY6foF3vJiv/VxiGi2WWvz04c4OpoXgIB37GeaF6ILFtGhHZSMA7hL/6nGmEHeRRADXXWQ1
QCryptographicHash *hash
You leak this instance, why do you create it on the heap at all?
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Hi
- I must be dumb or not know something.
We all know here you are not dumb and there is a vaste universe of stuff we dont know but
QByteArray::constData() should be perfectly fine
but make sure the bytearray lives long enough for for crypt() to use it while still in scope. - I must be dumb or not know something.
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Hashes are normally printed as base64 and so it's
$6$Lt5bExFakB7nrZEN$3KHS5HLNe8UwSxGQY6foF3vJiv/VxiGi2WWvz04c4OpoXgIB37GeaF6ILFtGhHZSMA7hL/6nGmEHeRRADXXWQ1
QCryptographicHash *hash
You leak this instance, why do you create it on the heap at all?
wrote on 17 Jun 2021, 17:06 last edited by@Christian-Ehrlicher my bad but this is inly excerpt. In the program it is a member and is deleted in the destructor.
And it is on the heap since I don't know how to initialise it otherwise (method selection). One of the constrains I face is that it has to be SHA-512 and only that.So you say QByteArray::toBase64 should suffice?
@mrjj I examined and tested the code from which excerpts are here, worked over 100 times both in loop with no wait and waiting for user input.
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@Christian-Ehrlicher my bad but this is inly excerpt. In the program it is a member and is deleted in the destructor.
And it is on the heap since I don't know how to initialise it otherwise (method selection). One of the constrains I face is that it has to be SHA-512 and only that.So you say QByteArray::toBase64 should suffice?
@mrjj I examined and tested the code from which excerpts are here, worked over 100 times both in loop with no wait and waiting for user input.
@artwaw said in Is there a way to make output from QCryptographicHash readable QByteArray?:
And it is on the heap since I don't know how to initialise it otherwise (method selection).
I don't understand this? Why does
QCryptographicHash hash(QCryptographicHash::Sha512);
not work?
So you say QByteArray::toBase64 should suffice?
Yes
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@Christian-Ehrlicher my bad but this is inly excerpt. In the program it is a member and is deleted in the destructor.
And it is on the heap since I don't know how to initialise it otherwise (method selection). One of the constrains I face is that it has to be SHA-512 and only that.So you say QByteArray::toBase64 should suffice?
@mrjj I examined and tested the code from which excerpts are here, worked over 100 times both in loop with no wait and waiting for user input.
wrote on 17 Jun 2021, 17:28 last edited byThis post is deleted! -
wrote on 17 Jun 2021, 17:32 last edited by artwaw
IT WORKS!
Thank you!@Christian-Ehrlicher That works, of course. But outside of the example it looks like this:
I wrapped all those hash-generating bits into a small class. For convenience, I have there:private: QRandomGenerator generator; QCryptographicHash *hash;
In the constructor I init the generator and the hash. So I have
hash = new QCryptographicHash(QCryptographicHash::Sha512);
that is later deleted in the destructor. It apparently is a weak day for me but I failed to find a way of this private member NOT to be on the heap.EDIT:
@JonB I saw your comment :)
I understood, just at this hour I am not entirely online, just from time to time :) -
IT WORKS!
Thank you!@Christian-Ehrlicher That works, of course. But outside of the example it looks like this:
I wrapped all those hash-generating bits into a small class. For convenience, I have there:private: QRandomGenerator generator; QCryptographicHash *hash;
In the constructor I init the generator and the hash. So I have
hash = new QCryptographicHash(QCryptographicHash::Sha512);
that is later deleted in the destructor. It apparently is a weak day for me but I failed to find a way of this private member NOT to be on the heap.EDIT:
@JonB I saw your comment :)
I understood, just at this hour I am not entirely online, just from time to time :)wrote on 17 Jun 2021, 17:37 last edited by JonB@artwaw
Personally I don't worry about heap vs stack as some others do, when I did Python it's all heap anyway. And sometimes I heap to avoid include dependencies in header files.But why can't you have
QCryptographicHash hash(QCryptographicHash::Sha512);
as the member variable instead of pointer? -
@artwaw
Personally I don't worry about heap vs stack as some others do, when I did Python it's all heap anyway. And sometimes I heap to avoid include dependencies in header files.But why can't you have
QCryptographicHash hash(QCryptographicHash::Sha512);
as the member variable instead of pointer? -
@JonB When I do:
private: QCryptographicHash hash(QCryptographicHash::Sha512);
I get instant
/Users/(username)/cpp/512hash/cryptoclass/cryptoclass.h:24: error: no type named 'Sha512' in 'QCryptographicHash'
wrote on 17 Jun 2021, 17:49 last edited by JonB@artwaw
Ah! That will be because you are in the "sometimes I heap to avoid include dependencies in header files" I mentioned :)Intentionally or not, in your
.h
file you have preceded this line withclass QCryptographicHash;
That allows
QCryptographicHash *
declarations to the incomplete type.You will need
#include <QCryptographicHash>
to make the declaration acceptable. If that is what you wish to do.
I see for example you alreday have
QRandomGenerator generator;
so you have chosen to do that one with include.
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@artwaw
Ah! That will be because you are in the "sometimes I heap to avoid include dependencies in header files" I mentioned :)Intentionally or not, in your
.h
file you have preceded this line withclass QCryptographicHash;
That allows
QCryptographicHash *
declarations to the incomplete type.You will need
#include <QCryptographicHash>
to make the declaration acceptable. If that is what you wish to do.
I see for example you alreday have
QRandomGenerator generator;
so you have chosen to do that one with include.
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@JonB When I do:
private: QCryptographicHash hash(QCryptographicHash::Sha512);
I get instant
/Users/(username)/cpp/512hash/cryptoclass/cryptoclass.h:24: error: no type named 'Sha512' in 'QCryptographicHash'
wrote on 17 Jun 2021, 17:55 last edited by@artwaw said in Is there a way to make output from QCryptographicHash readable QByteArray?:
I get instant
/Users/(username)/cpp/512hash/cryptoclass/cryptoclass.h:24: error: no type named 'Sha512' in 'QCryptographicHash'
Then I have no idea why you get a "no type" error for
QCryptographicHash hash(QCryptographicHash::Sha512);
in a
.h
but not in a.cpp
or whyhash = new QCryptographicHash(QCryptographicHash::Sha512);
is acceptable.
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@artwaw said in Is there a way to make output from QCryptographicHash readable QByteArray?:
I get instant
/Users/(username)/cpp/512hash/cryptoclass/cryptoclass.h:24: error: no type named 'Sha512' in 'QCryptographicHash'
Then I have no idea why you get a "no type" error for
QCryptographicHash hash(QCryptographicHash::Sha512);
in a
.h
but not in a.cpp
or whyhash = new QCryptographicHash(QCryptographicHash::Sha512);
is acceptable.
wrote on 17 Jun 2021, 17:57 last edited by artwaw@JonB I can live with one pair of new/delete :)
Thank you all who contributed and especially to @Christian-Ehrlicher for pointing me out the obvious.
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