104 lines
4.6 KiB
C++
104 lines
4.6 KiB
C++
// scrypt.h - written and placed in public domain by Jeffrey Walton.
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// Based on reference source code by Colin Percival.
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/// \file scrypt.h
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/// \brief Classes for Scrypt from RFC 7914
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/// \sa <A HREF="https://www.tarsnap.com/scrypt/scrypt.pdf">Stronger Key Derivation via
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/// Sequential Memory-Hard Functions</a>,
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/// <A HREF="https://www.tarsnap.com/scrypt.html">The scrypt key derivation function</A>
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/// and <A HREF="https://tools.ietf.org/html/rfc7914">RFC 7914, The scrypt Password-Based
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/// Key Derivation Function</A>
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/// \since Crypto++ 7.0
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#ifndef CRYPTOPP_SCRYPT_H
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#define CRYPTOPP_SCRYPT_H
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#include "cryptlib.h"
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#include "secblock.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief Scrypt key derivation function
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/// \details The Crypto++ implementation uses OpenMP to accelerate the derivation when
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/// available.
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/// \details The Crypto++ implementation of Scrypt is limited by C++ datatypes. For
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/// example, the library is limited to a derived key length of <tt>SIZE_MAX</tt>,
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/// and not <tt>(2^32 - 1) * 32</tt>.
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/// \sa <A HREF="https://www.tarsnap.com/scrypt/scrypt.pdf">Stronger Key Derivation via
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/// Sequential Memory-Hard Functions</A>,
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/// <A HREF="https://www.tarsnap.com/scrypt.html">The scrypt key derivation function</A>
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/// and <A HREF="https://tools.ietf.org/html/rfc7914">RFC 7914, The scrypt Password-Based
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/// Key Derivation Function</A>
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/// \since Crypto++ 7.0
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class Scrypt : public KeyDerivationFunction
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{
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public:
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virtual ~Scrypt() {}
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static std::string StaticAlgorithmName () {
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return "scrypt";
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}
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// KeyDerivationFunction interface
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std::string AlgorithmName() const {
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return StaticAlgorithmName();
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}
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// KeyDerivationFunction interface
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size_t MaxDerivedKeyLength() const {
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return static_cast<size_t>(0)-1;
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}
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// KeyDerivationFunction interface
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size_t GetValidDerivedLength(size_t keylength) const;
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// KeyDerivationFunction interface
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size_t DeriveKey(byte *derived, size_t derivedLen, const byte *secret, size_t secretLen,
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const NameValuePairs& params) const;
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/// \brief Derive a key from a seed
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/// \param derived the derived output buffer
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/// \param derivedLen the size of the derived buffer, in bytes
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/// \param secret the seed input buffer
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/// \param secretLen the size of the secret buffer, in bytes
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/// \param salt the salt input buffer
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/// \param saltLen the size of the salt buffer, in bytes
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/// \param cost the CPU/memory cost factor
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/// \param blockSize the block size
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/// \param parallelization the parallelization factor
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/// \return the number of iterations performed
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/// \throw InvalidDerivedKeyLength if <tt>derivedLen</tt> is invalid for the scheme
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/// \details DeriveKey() provides a standard interface to derive a key from
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/// a seed and other parameters. Each class that derives from KeyDerivationFunction
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/// provides an overload that accepts most parameters used by the derivation function.
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/// \details The CPU/Memory <tt>cost</tt> parameter ("N" in the documents) must be
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/// larger than 1, a power of 2, and less than <tt>2^(128 * r / 8)</tt>.
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/// \details The parameter <tt>blockSize</tt> ("r" in the documents) specifies the block
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/// size.
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/// \details The <tt>parallelization</tt> parameter ("p" in the documents) is a positive
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/// integer less than or equal to <tt>((2^32-1) * 32) / (128 * r)</tt>. Due to Microsoft
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/// and its OpenMP 2.0 implementation <tt>parallelization</tt> is limited to
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/// <tt>std::numeric_limits<int>::max()</tt>.
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/// \details Scrypt always returns 1 because it only performs 1 iteration. Other
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/// derivation functions, like PBKDF's, will return more interesting values.
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/// \details The Crypto++ implementation of Scrypt is limited by C++ datatypes. For
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/// example, the library is limited to a derived key length of <tt>SIZE_MAX</tt>,
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/// and not <tt>(2^32 - 1) * 32</tt>.
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size_t DeriveKey(byte *derived, size_t derivedLen, const byte *secret, size_t secretLen,
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const byte *salt, size_t saltLen, word64 cost=2, word64 blockSize=8, word64 parallelization=1) const;
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protected:
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enum {defaultCost=2, defaultBlockSize=8, defaultParallelization=1};
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// KeyDerivationFunction interface
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const Algorithm & GetAlgorithm() const {
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return *this;
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}
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inline void ValidateParameters(size_t derivedlen, word64 cost, word64 blockSize, word64 parallelization) const;
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};
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NAMESPACE_END
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#endif // CRYPTOPP_SCRYPT_H
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