PBKDF2.h

/* Copyright (C) 2013, tkmorris <mauricioarozi@gmail.com>
   Copyright (C) 2014, Stefan Hacker <dd0t@users.sourceforge.net>

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*/
#ifndef MUMBLE_MURMUR_PBKDF2_H_
#define MUMBLE_MURMUR_PBKDF2_H_

#include <stddef.h>

class QString;

///
/// Fully static wrapper class for PBKF2 password hashing functionality used in Murmur.
/// 
/// @note Using int all over the place because OpenSSL uses them in its C interface
///       and we want to make sure not to parameterize it in unexpected ways.
/// @warning Operations in this class that experience internal failure will abort
///          program execution using qFatal.
///
class PBKDF2 {
	public:
		///
		/// @return Upper bound on iterations possible in
		///         BENCHMARK_DURATION_TARGET_IN_MS on this machine.
		///
		static int benchmark();
		
		/// Performs a PBKDF2 hash operation using EVP_sha384.
		/// 
		/// @param hexSalt Hex encoded salt to use in operation.
		/// @param password Password to hash.
		/// @param iterationCount Number of PBKDF2 iterations to apply.
		/// @return Hex encoded password hash of DERIVED_KEY_LENGTH octets.
		///
		static QString getHash(const QString& hexSalt,
		                       const QString& password,
		                       int iterationCount);
		
		///
		/// @return SALT_LENGTH octets of hex encoded random salt.
		///
		static QString getSalt();
		
		/// Length of hash in octets
		static const int DERIVED_KEY_LENGTH = 48;
		/// Length salt in octests
		static const int SALT_LENGTH = 8;
		
		/// Duration for hash operation the benchmark function should target
		static const int BENCHMARK_DURATION_TARGET_IN_MS = 10;
		/// Benchmark returns highest iteration number of N benchmark attemps
		static const size_t BENCHMARK_N = 40;
		/// Lower bound of iteration count returned by benchmark
		/// regardless of duration (should be divisible by 2)
		static const int BENCHMARK_MINIMUM_ITERATION_COUNT = 1000;

};

#endif // MUMBLE_MURMUR_PBKDF2_H_