src/mbedTLS++/CtrDrbgContext.cpp


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// CtrDrbgContext.cpp

// Implements the cCtrDrbgContext class representing a wrapper over CTR-DRBG implementation in mbedTLS

#include "Globals.h"
#include "CtrDrbgContext.h"
#include "EntropyContext.h"


cCtrDrbgContext::cCtrDrbgContext(void) :
	m_EntropyContext(std::make_shared<cEntropyContext>()), m_IsValid(false)
{
	mbedtls_ctr_drbg_init(&m_CtrDrbg);
}


cCtrDrbgContext::cCtrDrbgContext(const std::shared_ptr<cEntropyContext> & a_EntropyContext) :
	m_EntropyContext(a_EntropyContext), m_IsValid(false)
{
	mbedtls_ctr_drbg_init(&m_CtrDrbg);
}


int cCtrDrbgContext::Initialize(const void * a_Custom, size_t a_CustomSize)
{
	if (m_IsValid)
	{
		// Already initialized
		return 0;
	}

	int res = mbedtls_ctr_drbg_seed(
		&m_CtrDrbg,
		mbedtls_entropy_func,
		&(m_EntropyContext->m_Entropy),
		static_cast<const unsigned char *>(a_Custom),
		a_CustomSize
	);
	m_IsValid = (res == 0);
	return res;
}