Convert CryptoPP::Integer to LPCTSTR

Question

I can't find the right code to convert a CryptoPP::Integer (from a RSA key generation) to a LPCTSTR (I want to store the key in the registry). Could you help me ?

Thanks you !

Answer 1

... convert a CryptoPP::Integer (from a RSA key generation) to a LPCTSTR (I want to store the key in the registry). Could you help me ?

Something like the following should do. The Integer class overloads operator<< in integer.h:

Integer n("0x0123456789012345678901234567890123456789");
ostringstream oss;    
oss << std::hex << n;

string str(oss.str());
LPCSTR ptr = str.c_str();

The Integer class always prints a suffix when using the insertion operator. In the code above, a h will be appended because of std::hex. So you might want to add:

string str(oss.str());
str.erase(str.end() - 1);

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Another way to do it is use the function IntToString<Integer>() from misc.h. However, it only works on narrow strings, and not wide strings.

Integer n("0x0123456789012345678901234567890123456789");
string val = IntToString(n, 16)

IntToString does not print the suffix. However, hacks are needed to print the string in uppercase (as shown in the manual).