First, thanks for the response. I implemented it without using the
intermediate string, but it came back with the same results [gibberish
after first 0x00]. I am using this simply as an interface to GCM
encryption/decryption, and thus I have valid pointers [along with
their validation] accounted for. In my test I have [simplified]
int main(int argc, char *argv[])
{
TEXT_SIZE = 256; // technically a passed in argument, but for
simplicity
byte key[32];
byte iv[12];
byte plainText[TEXT_SIZE];
byte *encoded, *decoded;
int size, status;
// assignments (char_to_byte, is verified to be working turning hex
as text to hex values)
iv = char_to_byte("000101353334331718192021", 12);
key =
char_to_byte("81cf7b4b4cca0330e1ef876e8cdc5beef20da8ba2b075a4b6f5748fed2859f2f",
32);
memset(plainText, 0x61, TEXT_SIZE);
memset((plainText+20), 0x00, 1); /// example 0x00 entry
encoded = (byte*)malloc(TEXT_SIZE+4);
memset(encoded, 0x00, TEXT_SIZE+4);
decoded = (byte*)malloc(TEXT_SIZE);
memset(decoded, 0x00, TEXT_SIZE);
// print data ...
// ENCRYPTION
size = TEXT_SIZE;
status = encrypt(iv, plainText, &size, encoded);
if (status = FAILURE)
{
... // print failure, exit
}
// print encoded ...
status = decrypt(iv, encoded, &size, decoded);
if (status = FAILURE)
{
... // print failure, exit
}
// print decoded ...
// the decoded values are correct up to the point of the first
0x00 instance, after that it seems like gibberish
}
On Jan 19, 2:08 pm, Rafael Vargas <[email protected]> wrote:
> This probably has to do with the fact that you are using std::string as a
> intermediate container, but maybe this would work (not actually tried to
> compile and run it)
>
> int encrypt(byte iv[12], const byte *in, int *size, byte *out)
> {
> try
> {
> GCM<AES>::Encryption e;
> e.SetKeyWithIv(key, 32, iv, 12);
>
> AuthenticatedEncryptionFilter ef(e, new ArraySink(out, *size -
> 4),false, 4);
> ef.ChannelPut("", in, *size);
> ef.ChannelMessageEnd("");
> *size -= 4;
> }
> catch
> {
> ... // print exception; return failure
> }
> return (1); // success
>
> }
>
> As you can see, I've removed the intermediary containers. As the
> std::string constructor was probably not even looking for anything after
> the first 0x00. But this functions assumes that all pointers are valid and
> that the out pointer was allocated with enough space. You should probably
> be using ByteQueue and ArraySource/ArraySink, and SecByteBlock...
>
> Hope this helps...
>
> --
> Rafael Vargas
>
> 2012/1/19 ZBrown <[email protected]>
>
>
>
>
>
>
>
> > I am having an issue in which I encrypt my data, and it seems to be
> > working; however, when I attempt to decrypt the data it returns
> > gibberish after a 0x00 value. For instance I *send in a byte[256]
> > that contains all 0x61, with several 0x00* interjected. I am doing
> > this as a proof of concept, being that I would like to use the GCM
> > model to encrypt data that may contain 0x00. I have verified my key,
> > iv, and const byte *in (including mac) and all seems to go threw
> > encrypt to decrypt correctly.
>
> > The issue I have is that the data after any 0x00 is gibberish from the
> > statement:
> > if (n > 0) { df.Get(out, n); }
>
> > Is this not supported? Am I implementing it incorrectly for this type
> > of execution?
>
> > My Encryption:
>
> > int encrypt(byte iv[12], const byte *in, int *size, byte *out)
> > {
> > string messageData = (char*)in;
> > string tempOut;
> > try
> > {
> > GCM<AES>::Encryption e;
> > e.SetKeyWithIv(key, 32, iv, 12);
>
> > AuthenticatedEncryptionFilter ef(e, new StringSink(tempOut),
> > false, 4);
> > ef.ChannelPut("", (const byte*)messageData.data(), *size);
> > ef.ChannelMessageEnd("");
> > memcpy(out, tempOut.data(), *size - 4);
> > *size -= 4;
> > }
> > catch
> > {
> > ... // print exception; return failure
> > }
>
> > return (1); // success
> > }
>
> > My Decryption:
>
> > int decrypt(byte iv[12], const byte *in, int *size, byte *out)
> > {
> > string ciper = (char*)in;
> > try
> > {
> > GCM<AES>::Decryption d;
> > d.SetKeyWithIV(key, 32, iv, 12);
>
> > string enc = cipher.substr(0, *size - 4);
> > string mac = cipher.substr(*size - 4);
>
> > AuthenticatedDecryptionFilter df(d, NULL,
> > AuthenticatedDecryptionFilter::MAC_AT_END ||
> > AuthenticatedDecryptionFilter::THROW_EXCEPTION, 4);
> > df.ChannelPut("", (const byte*)enc.data(), enc.size());
> > df.ChannelPut("", (const byte*)mac.data(), mac.size());
> > df.ChannelMessageEnd("");
>
> > bool b = false;
> > b = df.GetLastResult();
> > assert(true == b);
>
> > size_t n = (size_t)-1;
> > df.SetRetrievalChannel("");
> > n = (size_t)df.MaxRetrievable();
>
> > if (n > 0) { df.Get(out, n); }
> > }
> > catch
> > {
> > ... // print exception; return failure
> > }
>
> > return(1); // success
> > }
>
> > --
> > You received this message because you are subscribed to the "Crypto++
> > Users" Google Group.
> > To unsubscribe, send an email to
> > [email protected].
> > More information about Crypto++ and this group is available at
> >http://www.cryptopp.com.
--
You received this message because you are subscribed to the "Crypto++ Users"
Google Group.
To unsubscribe, send an email to [email protected].
More information about Crypto++ and this group is available at
http://www.cryptopp.com.
