ext-cryptopp/drbg.h
Jeffrey Walton 2868452193
Add NIST SP800-90A HMAC_DRBG generator
Move bodies out-of-line
Whitespace
2017-02-07 08:51:58 -05:00

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34 KiB
C++

// drbg.h - written and placed in public domain by Jeffrey Walton.
// Copyright assigned to Crypto++ project.
//! \file drbg.h
//! \brief Classes for NIST DRBGs from SP 800-90A
//! \sa <A HREF="http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf">Recommendation
//! for Random Number Generation Using Deterministic Random Bit Generators, Rev 1 (June 2015)</A>
//! \since Crypto++ 5.7
#ifndef CRYPTOPP_NIST_DRBG_H
#define CRYPTOPP_NIST_DRBG_H
#include "cryptlib.h"
#include "secblock.h"
NAMESPACE_BEGIN(CryptoPP)
//! \class NIST_DRBG
//! \brief Interface for NIST DRBGs from SP 800-90A
//! \details NIST_DRBG is the base class interface for NIST DRBGs from SP 800-90A Rev 1 (June 2015)
//! \sa <A HREF="http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf">Recommendation
//! for Random Number Generation Using Deterministic Random Bit Generators, Rev 1 (June 2015)</A>
//! \since Crypto++ 5.7
class NIST_DRBG : public RandomNumberGenerator
{
public:
//! \brief Exception thrown when a NIST DRBG encounters an error
class Err : public Exception
{
public:
explicit Err(const std::string &c, const std::string &m)
: Exception(OTHER_ERROR, c + ": " + m) {}
};
public:
virtual ~NIST_DRBG() {}
//! \brief Determines if a generator can accept additional entropy
//! \return true
//! \details All NIST_DRBG return true
virtual bool CanIncorporateEntropy() const {return true;}
//! \brief Update RNG state with additional unpredictable values
//! \param input the entropy to add to the generator
//! \param length the size of the input buffer
//! \throws NIST_DRBG::Err if the generator is reseeded with insufficient entropy
//! \details NIST instantiation and reseed requirements demand the generator is constructed with at least <tt>MINIMUM_ENTROPY</tt>
//! entropy. The byte array for <tt>input</tt> must meet <A HREF ="http://csrc.nist.gov/publications/PubsSPs.html">NIST
//! SP 800-90B or SP 800-90C</A> requirements.
virtual void IncorporateEntropy(const byte *input, size_t length)=0;
//! \brief Update RNG state with additional unpredictable values
//! \param entropy the entropy to add to the generator
//! \param entropyLength the size of the input buffer
//! \param additional additional input to add to the generator
//! \param additionaLength the size of the additional input buffer
//! \throws NIST_DRBG::Err if the generator is reseeded with insufficient entropy
//! \details IncorporateEntropy() is an overload provided to match NIST requirements. NIST instantiation and
//! reseed requirements demand the generator is constructed with at least <tt>MINIMUM_ENTROPY</tt> entropy.
//! The byte array for <tt>entropy</tt> must meet <A HREF ="http://csrc.nist.gov/publications/PubsSPs.html">NIST
//! SP 800-90B or SP 800-90C</A> requirements.
virtual void IncorporateEntropy(const byte *entropy, size_t entropyLength, const byte* additional, size_t additionaLength)=0;
//! \brief Generate random array of bytes
//! \param output the byte buffer
//! \param size the length of the buffer, in bytes
//! \throws NIST_DRBG::Err if a reseed is required
//! \throws NIST_DRBG::Err if the size exceeds <tt>MAXIMUM_BYTES_PER_REQUEST</tt>
virtual void GenerateBlock(byte *output, size_t size)=0;
//! \brief Generate random array of bytes
//! \param additional additional input to add to the generator
//! \param additionaLength the size of the additional input buffer
//! \param output the byte buffer
//! \param size the length of the buffer, in bytes
//! \throws NIST_DRBG::Err if a reseed is required
//! \throws NIST_DRBG::Err if the size exceeds <tt>MAXIMUM_BYTES_PER_REQUEST</tt>
//! \details GenerateBlock() is an overload provided to match NIST requirements. The byte array for <tt>additional</tt>
//! input is optional. If present the additional randomness is mixed before generating the output bytes.
virtual void GenerateBlock(const byte* additional, size_t additionaLength, byte *output, size_t size)=0;
//! \brief Provides the security strength
//! \returns The security strength of the generator, in bytes
//! \details The equivalent class constant is <tt>SECURITY_STRENGTH</tt>
virtual unsigned int GetSecurityStrength() const=0;
//! \brief Provides the seed length
//! \returns The seed size of the generator, in bytes
//! \details The equivalent class constant is <tt>SEED_LENGTH</tt>. The size is
//! used to maintain internal state of <tt>V</tt> and <tt>C</tt>.
virtual unsigned int GetSeedLength() const=0;
//! \brief Provides the minimum entropy size
//! \returns The minimum entropy size required by the generator, in bytes
//! \details The equivalent class constant is <tt>MINIMUM_ENTROPY</tt>. All NIST DRBGs must be instaniated with at least
//! <tt>MINIMUM_ENTROPY</tt> bytes of entropy. The bytes must meet <A
//! HREF="http://csrc.nist.gov/publications/PubsSPs.html">NIST SP 800-90B or SP 800-90C</A> requirements.
virtual unsigned int GetMinEntropy() const=0;
//! \brief Provides the maximum entropy size
//! \returns The maximum entropy size that can be consumed by the generator, in bytes
//! \details The equivalent class constant is <tt>MAXIMUM_ENTROPY</tt>. The bytes must meet <A
//! HREF="http://csrc.nist.gov/publications/PubsSPs.html">NIST SP 800-90B or SP 800-90C</A> requirements.
//! <tt>MAXIMUM_ENTROPY</tt> has been reduced from 2<sup>35</sup> to <tt>INT_MAX</tt> to fit the underlying C++ datatype.
virtual unsigned int GetMaxEntropy() const=0;
//! \brief Provides the minimum nonce size
//! \returns The minimum nonce size recommended for the generator, in bytes
//! \details The equivalent class constant is <tt>MINIMUM_NONCE</tt>. If a nonce is not required then
//! <tt>MINIMUM_NONCE</tt> is 0. <tt>Hash_DRBG</tt> does not require a nonce, while <tt>HMAC_DRBG</tt>
//! and <tt>CTR_DRBG</tt> require a nonce.
virtual unsigned int GetMinNonce() const=0;
//! \brief Provides the maximum nonce size
//! \returns The maximum nonce that can be consumed by the generator, in bytes
//! \details The equivalent class constant is <tt>MAXIMUM_NONCE</tt>. <tt>MAXIMUM_NONCE</tt> has been reduced from
//! 2<sup>35</sup> to <tt>INT_MAX</tt> to fit the underlying C++ datatype. If a nonce is not required then
//! <tt>MINIMUM_NONCE</tt> is 0. <tt>Hash_DRBG</tt> does not require a nonce, while <tt>HMAC_DRBG</tt>
//! and <tt>CTR_DRBG</tt> require a nonce.
virtual unsigned int GetMaxNonce() const=0;
//! \brief Provides the maximum size of a request to GenerateBlock
//! \returns The the maximum size of a request to GenerateBlock(), in bytes
//! \details The equivalent class constant is <tt>MAXIMUM_BYTES_PER_REQUEST</tt>
virtual unsigned int GetMaxBytesPerRequest() const=0;
//! \brief Provides the maximum number of requests before a reseed
//! \returns The the maximum number of requests before a reseed, in bytes
//! \details The equivalent class constant is <tt>MAXIMUM_REQUESTS_BEFORE_RESEED</tt>.
//! <tt>MAXIMUM_REQUESTS_BEFORE_RESEED</tt> has been reduced from 2<sup>48</sup> to <tt>INT_MAX</tt>
//! to fit the underlying C++ datatype.
virtual unsigned int GetMaxRequestBeforeReseed() const=0;
protected:
virtual void DRBG_Instantiate(const byte* entropy, size_t entropyLength,
const byte* nonce, size_t nonceLength, const byte* personalization, size_t personalizationLength)=0;
virtual void DRBG_Reseed(const byte* entropy, size_t entropyLength, const byte* additional, size_t additionaLength)=0;
};
// *************************************************************
//! \class Hash_DRBG
//! \tparam HASH NIST approved hash derived from HashTransformation
//! \tparam STRENGTH security strength, in bytes
//! \tparam SEEDLENGTH seed length, in bytes
//! \brief Hash_DRBG from SP 800-90A Rev 1 (June 2015)
//! \details The NIST Hash DRBG is instantiated with a number of parameters. Two of the parameters,
//! Security Strength and Seed Length, depend on the hash and are specified as template parameters.
//! The remaining parameters are included in the class. The parameters and their values are listed
//! in NIST SP 800-90A Rev. 1, Table 2: Definitions for Hash-Based DRBG Mechanisms (p.38).
//! \details Some parameters have been reduce to fit C++ datatypes. For example, NIST allows upto 2<sup>48</sup> requests
//! before a reseed. However, Hash_DRBG limits it to <tt>INT_MAX</tt> due to the limited data range of an int.
//! \sa <A HREF="http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf">Recommendation
//! for Random Number Generation Using Deterministic Random Bit Generators, Rev 1 (June 2015)</A>
//! \since Crypto++ 5.7
template <typename HASH=SHA256, unsigned int STRENGTH=128/8, unsigned int SEEDLENGTH=440/8>
class Hash_DRBG : public NIST_DRBG, public NotCopyable
{
public:
CRYPTOPP_CONSTANT(SECURITY_STRENGTH=STRENGTH)
CRYPTOPP_CONSTANT(SEED_LENGTH=SEEDLENGTH)
CRYPTOPP_CONSTANT(MINIMUM_ENTROPY=STRENGTH)
CRYPTOPP_CONSTANT(MINIMUM_NONCE=0)
CRYPTOPP_CONSTANT(MINIMUM_ADDITIONAL=0)
CRYPTOPP_CONSTANT(MINIMUM_PERSONALIZATION=0)
CRYPTOPP_CONSTANT(MAXIMUM_ENTROPY=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_NONCE=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_ADDITIONAL=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_PERSONALIZATION=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_BYTES_PER_REQUEST=65536)
CRYPTOPP_CONSTANT(MAXIMUM_REQUESTS_BEFORE_RESEED=INT_MAX)
//! \brief Construct a Hash DRBG
//! \param entropy the entropy to instantiate the generator
//! \param entropyLength the size of the entropy buffer
//! \param nonce additional input to instantiate the generator
//! \param nonceLength the size of the nonce buffer
//! \param personalization additional input to instantiate the generator
//! \param personalizationLength the size of the personalization buffer
//! \throws NIST_DRBG::Err if the generator is instantiated with insufficient entropy
//! \details All NIST DRBGs must be instaniated with at least <tt>MINIMUM_ENTROPY</tt> bytes of entropy.
//! The byte array for <tt>entropy</tt> must meet <A HREF ="http://csrc.nist.gov/publications/PubsSPs.html">NIST
//! SP 800-90B or SP 800-90C</A> requirements.
//! \details The <tt>nonce</tt> and <tt>personalization</tt> are optional byte arrays. If <tt>nonce</tt> is supplied,
//! then it should be at least <tt>MINIMUM_NONCE</tt> bytes of entropy.
//! \details An example of instantiating a SHA256 generator is shown below.
//! The example provides more entropy than required for SHA256. The <tt>NonblockingRng</tt> meets the
//! requirements of <A HREF ="http://csrc.nist.gov/publications/PubsSPs.html">NIST SP 800-90B or SP 800-90C</A>.
//! RDRAND() and RDSEED() generators would work as well.
//! <pre>
//! SecByteBlock entropy(48), result(128);
//! NonblockingRng prng;
//! RandomNumberSource rns(prng, entropy.size(), new ArraySink(entropy, entropy.size()));
//!
//! Hash_DRBG<SHA256, 128/8, 440/8> drbg(entropy, 32, entropy+32, 16);
//! drbg.GenerateBlock(result, result.size());
//! </pre>
Hash_DRBG(const byte* entropy, size_t entropyLength=STRENGTH, const byte* nonce=NULL,
size_t nonceLength=0, const byte* personalization=NULL, size_t personalizationLength=0)
: NIST_DRBG(), m_c(SEEDLENGTH), m_v(SEEDLENGTH)
{
DRBG_Instantiate(entropy, entropyLength, nonce, nonceLength, personalization, personalizationLength);
}
unsigned int GetSecurityStrength() const {return SECURITY_STRENGTH;}
unsigned int GetSeedLength() const {return SEED_LENGTH;}
unsigned int GetMinEntropy() const {return MINIMUM_ENTROPY;}
unsigned int GetMaxEntropy() const {return MAXIMUM_ENTROPY;}
unsigned int GetMinNonce() const {return MINIMUM_NONCE;}
unsigned int GetMaxNonce() const {return MAXIMUM_NONCE;}
unsigned int GetMaxBytesPerRequest() const {return MAXIMUM_BYTES_PER_REQUEST;}
unsigned int GetMaxRequestBeforeReseed() const {return MAXIMUM_REQUESTS_BEFORE_RESEED;}
void IncorporateEntropy(const byte *input, size_t length)
{return DRBG_Reseed(input, length, NULL, 0);}
void IncorporateEntropy(const byte *entropy, size_t entropyLength, const byte* additional, size_t additionaLength)
{return DRBG_Reseed(entropy, entropyLength, additional, additionaLength);}
void GenerateBlock(byte *output, size_t size)
{return Hash_Generate(NULL, 0, output, size);}
void GenerateBlock(const byte* additional, size_t additionaLength, byte *output, size_t size)
{return Hash_Generate(additional, additionaLength, output, size);}
protected:
// 10.1.1.2 Instantiation of Hash_DRBG (p.39)
void DRBG_Instantiate(const byte* entropy, size_t entropyLength, const byte* nonce, size_t nonceLength,
const byte* personalization, size_t personalizationLength);
// 10.1.1.3 Reseeding a Hash_DRBG Instantiation (p.40)
void DRBG_Reseed(const byte* entropy, size_t entropyLength, const byte* additional, size_t additionaLength);
// 10.1.1.4 Generating Pseudorandom Bits Using Hash_DRBG (p.41)
void Hash_Generate(const byte* additional, size_t additionaLength, byte *output, size_t size);
// 10.3.1 Derivation Function Using a Hash Function (Hash_df) (p.49)
void Hash_Update(const byte* input1, size_t inlen1, const byte* input2, size_t inlen2,
const byte* input3, size_t inlen3, const byte* input4, size_t inlen4, byte* output, size_t outlen);
private:
SecByteBlock m_c, m_v;
word64 m_reseed;
};
// typedef Hash_DRBG<SHA1, 128/8, 440/8> Hash_SHA1_DRBG;
// typedef Hash_DRBG<SHA256, 128/8, 440/8> Hash_SHA256_DRBG;
// typedef Hash_DRBG<SHA384, 256/8, 888/8> Hash_SHA384_DRBG;
// typedef Hash_DRBG<SHA512, 256/8, 888/8> Hash_SHA512_DRBG;
// *************************************************************
//! \class HMAC_DRBG
//! \tparam HASH NIST approved hash derived from HashTransformation
//! \tparam STRENGTH security strength, in bytes
//! \tparam SEEDLENGTH seed length, in bytes
//! \brief HMAC_DRBG from SP 800-90A Rev 1 (June 2015)
//! \details The NIST Hash DRBG is instantiated with a number of parameters. Two of the parameters,
//! Security Strength and Seed Length, depend on the hash and are specified as template parameters.
//! The remaining parameters are included in the class. The parameters and their values are listed
//! in NIST SP 800-90A Rev. 1, Table 2: Definitions for Hash-Based DRBG Mechanisms (p.38).
//! \details Some parameters have been reduce to fit C++ datatypes. For example, NIST allows upto 2<sup>48</sup> requests
//! before a reseed. However, HMAC_DRBG limits it to <tt>INT_MAX</tt> due to the limited data range of an int.
//! \sa <A HREF="http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf">Recommendation
//! for Random Number Generation Using Deterministic Random Bit Generators, Rev 1 (June 2015)</A>
//! \since Crypto++ 5.7
template <typename HASH=SHA256, unsigned int STRENGTH=128/8, unsigned int SEEDLENGTH=440/8>
class HMAC_DRBG : public NIST_DRBG, public NotCopyable
{
public:
CRYPTOPP_CONSTANT(SECURITY_STRENGTH=STRENGTH)
CRYPTOPP_CONSTANT(SEED_LENGTH=SEEDLENGTH)
CRYPTOPP_CONSTANT(MINIMUM_ENTROPY=STRENGTH)
CRYPTOPP_CONSTANT(MINIMUM_NONCE=0)
CRYPTOPP_CONSTANT(MINIMUM_ADDITIONAL=0)
CRYPTOPP_CONSTANT(MINIMUM_PERSONALIZATION=0)
CRYPTOPP_CONSTANT(MAXIMUM_ENTROPY=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_NONCE=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_ADDITIONAL=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_PERSONALIZATION=INT_MAX)
CRYPTOPP_CONSTANT(MAXIMUM_BYTES_PER_REQUEST=65536)
CRYPTOPP_CONSTANT(MAXIMUM_REQUESTS_BEFORE_RESEED=INT_MAX)
//! \brief Construct a Hash DRBG
//! \param entropy the entropy to instantiate the generator
//! \param entropyLength the size of the entropy buffer
//! \param nonce additional input to instantiate the generator
//! \param nonceLength the size of the nonce buffer
//! \param personalization additional input to instantiate the generator
//! \param personalizationLength the size of the personalization buffer
//! \throws NIST_DRBG::Err if the generator is instantiated with insufficient entropy
//! \details All NIST DRBGs must be instaniated with at least <tt>MINIMUM_ENTROPY</tt> bytes of entropy.
//! The byte array for <tt>entropy</tt> must meet <A HREF ="http://csrc.nist.gov/publications/PubsSPs.html">NIST
//! SP 800-90B or SP 800-90C</A> requirements.
//! \details The <tt>nonce</tt> and <tt>personalization</tt> are optional byte arrays. If <tt>nonce</tt> is supplied,
//! then it should be at least <tt>MINIMUM_NONCE</tt> bytes of entropy.
//! \details An example of instantiating a SHA256 generator is shown below.
//! The example provides more entropy than required for SHA256. The <tt>NonblockingRng</tt> meets the
//! requirements of <A HREF ="http://csrc.nist.gov/publications/PubsSPs.html">NIST SP 800-90B or SP 800-90C</A>.
//! RDRAND() and RDSEED() generators would work as well.
//! <pre>
//! SecByteBlock entropy(48), result(128);
//! NonblockingRng prng;
//! RandomNumberSource rns(prng, entropy.size(), new ArraySink(entropy, entropy.size()));
//!
//! HMAC_DRBG<SHA256, 128/8, 440/8> drbg(entropy, 32, entropy+32, 16);
//! drbg.GenerateBlock(result, result.size());
//! </pre>
HMAC_DRBG(const byte* entropy, size_t entropyLength=STRENGTH, const byte* nonce=NULL,
size_t nonceLength=0, const byte* personalization=NULL, size_t personalizationLength=0)
: NIST_DRBG(), m_k(HASH::DIGESTSIZE), m_v(HASH::DIGESTSIZE)
{
DRBG_Instantiate(entropy, entropyLength, nonce, nonceLength, personalization, personalizationLength);
}
unsigned int GetSecurityStrength() const {return SECURITY_STRENGTH;}
unsigned int GetSeedLength() const {return SEED_LENGTH;}
unsigned int GetMinEntropy() const {return MINIMUM_ENTROPY;}
unsigned int GetMaxEntropy() const {return MAXIMUM_ENTROPY;}
unsigned int GetMinNonce() const {return MINIMUM_NONCE;}
unsigned int GetMaxNonce() const {return MAXIMUM_NONCE;}
unsigned int GetMaxBytesPerRequest() const {return MAXIMUM_BYTES_PER_REQUEST;}
unsigned int GetMaxRequestBeforeReseed() const {return MAXIMUM_REQUESTS_BEFORE_RESEED;}
void IncorporateEntropy(const byte *input, size_t length)
{return DRBG_Reseed(input, length, NULL, 0);}
void IncorporateEntropy(const byte *entropy, size_t entropyLength, const byte* additional, size_t additionaLength)
{return DRBG_Reseed(entropy, entropyLength, additional, additionaLength);}
void GenerateBlock(byte *output, size_t size)
{return HMAC_Generate(NULL, 0, output, size);}
void GenerateBlock(const byte* additional, size_t additionaLength, byte *output, size_t size)
{return HMAC_Generate(additional, additionaLength, output, size);}
protected:
// 10.1.2.3 Instantiation of HMAC_DRBG (p.45)
void DRBG_Instantiate(const byte* entropy, size_t entropyLength, const byte* nonce, size_t nonceLength,
const byte* personalization, size_t personalizationLength);
// 10.1.2.4 Reseeding a HMAC_DRBG Instantiation (p.46)
void DRBG_Reseed(const byte* entropy, size_t entropyLength, const byte* additional, size_t additionaLength);
// 10.1.2.5 Generating Pseudorandom Bits Using HMAC_DRBG (p.46)
void HMAC_Generate(const byte* additional, size_t additionaLength, byte *output, size_t size);
// 10.1.2.2 Derivation Function Using a HMAC Function (HMAC_Update) (p.44)
void HMAC_Update(const byte* input1, size_t inlen1, const byte* input2, size_t inlen2, const byte* input3, size_t inlen3);
private:
SecByteBlock m_k, m_v;
word64 m_reseed;
};
// typedef HMAC_DRBG<SHA1, 128/8, 440/8> HMAC_SHA1_DRBG;
// typedef HMAC_DRBG<SHA256, 128/8, 440/8> HMAC_SHA256_DRBG;
// typedef HMAC_DRBG<SHA384, 256/8, 888/8> HMAC_SHA384_DRBG;
// typedef HMAC_DRBG<SHA512, 256/8, 888/8> HMAC_SHA512_DRBG;
// *************************************************************
// 10.1.1.2 Instantiation of Hash_DRBG (p.39)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void Hash_DRBG<HASH, STRENGTH, SEEDLENGTH>::DRBG_Instantiate(const byte* entropy, size_t entropyLength, const byte* nonce, size_t nonceLength,
const byte* personalization, size_t personalizationLength)
{
// SP 800-90A, 8.6.3: The entropy input shall have entropy that is equal to or greater than the security
// strength of the instantiation. Additional entropy may be provided in the nonce or the optional
// personalization string during instantiation, or in the additional input during reseeding and generation,
// but this is not required and does not increase the "official" security strength of the DRBG
// instantiation that is recorded in the internal state.
CRYPTOPP_ASSERT(entropyLength >= MINIMUM_ENTROPY);
if (entropyLength < MINIMUM_ENTROPY)
throw NIST_DRBG::Err("Hash_DRBG", "Insufficient entropy during instantiate");
// SP 800-90A, Section 9, says we should throw if we have too much entropy, too large a nonce,
// or too large a persoanlization string. We warn in Debug builds, but do nothing in Release builds.
CRYPTOPP_ASSERT(entropyLength <= MAXIMUM_ENTROPY);
CRYPTOPP_ASSERT(nonceLength <= MAXIMUM_NONCE);
CRYPTOPP_ASSERT(personalizationLength <= MAXIMUM_PERSONALIZATION);
const byte zero = 0;
SecByteBlock t1(SEEDLENGTH), t2(SEEDLENGTH);
Hash_Update(entropy, entropyLength, nonce, nonceLength, personalization, personalizationLength, NULL, 0, t1, t1.size());
Hash_Update(&zero, 1, t1, t1.size(), NULL, 0, NULL, 0, t2, t2.size());
m_v.swap(t1); m_c.swap(t2);
m_reseed = 1;
}
// 10.1.1.3 Reseeding a Hash_DRBG Instantiation (p.40)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void Hash_DRBG<HASH, STRENGTH, SEEDLENGTH>::DRBG_Reseed(const byte* entropy, size_t entropyLength, const byte* additional, size_t additionaLength)
{
// SP 800-90A, 8.6.3: The entropy input shall have entropy that is equal to or greater than the security
// strength of the instantiation. Additional entropy may be provided in the nonce or the optional
// personalization string during instantiation, or in the additional input during reseeding and generation,
// but this is not required and does not increase the "official" security strength of the DRBG
// instantiation that is recorded in the internal state..
CRYPTOPP_ASSERT(entropyLength >= MINIMUM_ENTROPY);
if (entropyLength < MINIMUM_ENTROPY)
throw NIST_DRBG::Err("Hash_DRBG", "Insufficient entropy during reseed");
// SP 800-90A, Section 9, says we should throw if we have too much entropy, too large a nonce,
// or too large a persoanlization string. We warn in Debug builds, but do nothing in Release builds.
CRYPTOPP_ASSERT(entropyLength <= MAXIMUM_ENTROPY);
CRYPTOPP_ASSERT(additionaLength <= MAXIMUM_ADDITIONAL);
const byte zero = 0, one = 1;
SecByteBlock t1(SEEDLENGTH), t2(SEEDLENGTH);
Hash_Update(&one, 1, m_v, m_v.size(), entropy, entropyLength, additional, additionaLength, t1, t1.size());
Hash_Update(&zero, 1, t1, t1.size(), NULL, 0, NULL, 0, t2, t2.size());
m_v.swap(t1); m_c.swap(t2);
m_reseed = 1;
}
// 10.1.1.4 Generating Pseudorandom Bits Using Hash_DRBG (p.41)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void Hash_DRBG<HASH, STRENGTH, SEEDLENGTH>::Hash_Generate(const byte* additional, size_t additionaLength, byte *output, size_t size)
{
// Step 1
if (static_cast<word64>(m_reseed) >= static_cast<word64>(GetMaxRequestBeforeReseed()))
throw NIST_DRBG::Err("Hash_DRBG", "Reseed required");
if (size > GetMaxBytesPerRequest())
throw NIST_DRBG::Err("Hash_DRBG", "Request size exceeds limit");
// SP 800-90A, Section 9, says we should throw if we have too much entropy, too large a nonce,
// or too large a persoanlization string. We warn in Debug builds, but do nothing in Release builds.
CRYPTOPP_ASSERT(additionaLength <= MAXIMUM_ADDITIONAL);
// Step 2
if (additional && additionaLength)
{
HASH hash;
const byte two = 2;
SecByteBlock w(HASH::DIGESTSIZE);
hash.Update(&two, 1);
hash.Update(m_v, m_v.size());
hash.Update(additional, additionaLength);
hash.Final(w);
CRYPTOPP_ASSERT(SEEDLENGTH >= HASH::DIGESTSIZE);
int carry=0, i=SEEDLENGTH-1, j=HASH::DIGESTSIZE-1;
while(i>=0 && j>=0)
{
carry = m_v[i] + w[j] + carry;
m_v[i] = static_cast<byte>(carry);
carry >>= 8; i--; j--;
}
while (carry && i>=0)
{
carry = m_v[i] + carry;
m_v[i] = static_cast<byte>(carry);
carry >>= 8; i--;
}
}
// Step 3
{
HASH hash;
SecByteBlock data(m_v);
while (size)
{
hash.Update(data, data.size());
size_t count = STDMIN(size, (size_t)HASH::DIGESTSIZE);
hash.TruncatedFinal(output, count);
IncrementCounterByOne(data, static_cast<unsigned int>(data.size()));
output += count; size -= count;
}
}
// Steps 4-7
{
HASH hash;
const byte three = 3;
SecByteBlock h(HASH::DIGESTSIZE);
hash.Update(&three, 1);
hash.Update(m_v, m_v.size());
hash.Final(h);
CRYPTOPP_ASSERT(SEEDLENGTH >= HASH::DIGESTSIZE);
CRYPTOPP_ASSERT(HASH::DIGESTSIZE >= sizeof(m_reseed));
int carry=0, i=SEEDLENGTH-1, j=HASH::DIGESTSIZE-1, k=sizeof(m_reseed)-1;
while(i>=0 && j>=0 && k>=0)
{
carry = m_v[i] + m_c[i] + h[j] + GetByte<word64>(BIG_ENDIAN_ORDER, m_reseed, k) + carry;
m_v[i] = static_cast<byte>(carry);
carry >>= 8; i--; j--; k--;
}
while(i>=0 && j>=0)
{
carry = m_v[i] + m_c[i] + h[j] + carry;
m_v[i] = static_cast<byte>(carry);
carry >>= 8; i--; j--;
}
while (i>=0)
{
carry = m_v[i] + m_c[i] + carry;
m_v[i] = static_cast<byte>(carry);
carry >>= 8; i--;
}
}
m_reseed++;
}
// 10.3.1 Derivation Function Using a Hash Function (Hash_df) (p.49)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void Hash_DRBG<HASH, STRENGTH, SEEDLENGTH>::Hash_Update(const byte* input1, size_t inlen1, const byte* input2, size_t inlen2,
const byte* input3, size_t inlen3, const byte* input4, size_t inlen4, byte* output, size_t outlen)
{
HASH hash;
byte counter = 1;
word32 bits = ConditionalByteReverse(BIG_ENDIAN_ORDER, static_cast<word32>(outlen*8));
size_t count;
for (count=0; outlen; outlen -= count, output += count, counter++)
{
hash.Update(&counter, 1);
hash.Update(reinterpret_cast<const byte*>(&bits), 4);
if (input1 && inlen1)
hash.Update(input1, inlen1);
if (input2 && inlen2)
hash.Update(input2, inlen2);
if (input3 && inlen3)
hash.Update(input3, inlen3);
if (input4 && inlen4)
hash.Update(input4, inlen4);
count = STDMIN(outlen, (size_t)HASH::DIGESTSIZE);
hash.TruncatedFinal(output, count);
}
}
// *************************************************************
// 10.1.2.3 Instantiation of HMAC_DRBG (p.45)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void HMAC_DRBG<HASH, STRENGTH, SEEDLENGTH>::DRBG_Instantiate(const byte* entropy, size_t entropyLength, const byte* nonce, size_t nonceLength,
const byte* personalization, size_t personalizationLength)
{
// SP 800-90A, 8.6.3: The entropy input shall have entropy that is equal to or greater than the security
// strength of the instantiation. Additional entropy may be provided in the nonce or the optional
// personalization string during instantiation, or in the additional input during reseeding and generation,
// but this is not required and does not increase the "official" security strength of the DRBG
// instantiation that is recorded in the internal state.
CRYPTOPP_ASSERT(entropyLength >= MINIMUM_ENTROPY);
if (entropyLength < MINIMUM_ENTROPY)
throw NIST_DRBG::Err("HMAC_DRBG", "Insufficient entropy during instantiate");
// SP 800-90A, Section 9, says we should throw if we have too much entropy, too large a nonce,
// or too large a persoanlization string. We warn in Debug builds, but do nothing in Release builds.
CRYPTOPP_ASSERT(entropyLength <= MAXIMUM_ENTROPY);
CRYPTOPP_ASSERT(nonceLength <= MAXIMUM_NONCE);
CRYPTOPP_ASSERT(personalizationLength <= MAXIMUM_PERSONALIZATION);
std::fill(m_k.begin(), m_k.begin()+m_k.size(), byte(0));
std::fill(m_v.begin(), m_v.begin()+m_v.size(), byte(1));
HMAC_Update(entropy, entropyLength, nonce, nonceLength, personalization, personalizationLength);
m_reseed = 1;
}
// 10.1.2.4 Reseeding a HMAC_DRBG Instantiation (p.46)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void HMAC_DRBG<HASH, STRENGTH, SEEDLENGTH>::DRBG_Reseed(const byte* entropy, size_t entropyLength, const byte* additional, size_t additionaLength)
{
// SP 800-90A, 8.6.3: The entropy input shall have entropy that is equal to or greater than the security
// strength of the instantiation. Additional entropy may be provided in the nonce or the optional
// personalization string during instantiation, or in the additional input during reseeding and generation,
// but this is not required and does not increase the "official" security strength of the DRBG
// instantiation that is recorded in the internal state..
CRYPTOPP_ASSERT(entropyLength >= MINIMUM_ENTROPY);
if (entropyLength < MINIMUM_ENTROPY)
throw NIST_DRBG::Err("HMAC_DRBG", "Insufficient entropy during reseed");
// SP 800-90A, Section 9, says we should throw if we have too much entropy, too large a nonce,
// or too large a persoanlization string. We warn in Debug builds, but do nothing in Release builds.
CRYPTOPP_ASSERT(entropyLength <= MAXIMUM_ENTROPY);
CRYPTOPP_ASSERT(additionaLength <= MAXIMUM_ADDITIONAL);
HMAC_Update(entropy, entropyLength, additional, additionaLength, NULL, 0);
m_reseed = 1;
}
// 10.1.2.5 Generating Pseudorandom Bits Using HMAC_DRBG (p.46)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void HMAC_DRBG<HASH, STRENGTH, SEEDLENGTH>::HMAC_Generate(const byte* additional, size_t additionaLength, byte *output, size_t size)
{
// Step 1
if (static_cast<word64>(m_reseed) >= static_cast<word64>(GetMaxRequestBeforeReseed()))
throw NIST_DRBG::Err("HMAC_DRBG", "Reseed required");
if (size > GetMaxBytesPerRequest())
throw NIST_DRBG::Err("HMAC_DRBG", "Request size exceeds limit");
// SP 800-90A, Section 9, says we should throw if we have too much entropy, too large a nonce,
// or too large a persoanlization string. We warn in Debug builds, but do nothing in Release builds.
CRYPTOPP_ASSERT(additionaLength <= MAXIMUM_ADDITIONAL);
// Step 2
if (additional && additionaLength)
HMAC_Update(additional, additionaLength, NULL, 0, NULL, 0);
// Step 3
HMAC<HASH> hmac;
hmac.SetKey(m_k, m_k.size());
while (size)
{
hmac.Update(m_v, m_v.size());
hmac.TruncatedFinal(m_v, m_v.size());
size_t count = STDMIN(size, (size_t)HASH::DIGESTSIZE);
memcpy(output, m_v, count);
size -= count; output += count;
}
HMAC_Update(additional, additionaLength, NULL, 0, NULL, 0);
m_reseed++;
}
// 10.1.2.2 Derivation Function Using a HMAC Function (HMAC_Update) (p.44)
template <typename HASH, unsigned int STRENGTH, unsigned int SEEDLENGTH>
void HMAC_DRBG<HASH, STRENGTH, SEEDLENGTH>::HMAC_Update(const byte* input1, size_t inlen1, const byte* input2, size_t inlen2, const byte* input3, size_t inlen3)
{
const byte zero = 0, one = 1;
HMAC<HASH> hmac;
// Step 1
hmac.SetKey(m_k, m_k.size());
hmac.Update(m_v, m_v.size());
hmac.Update(&zero, 1);
if (input1 && inlen1)
hmac.Update(input1, inlen1);
if (input2 && inlen2)
hmac.Update(input2, inlen2);
if (input3 && inlen3)
hmac.Update(input3, inlen3);
hmac.TruncatedFinal(m_k, m_k.size());
// Step 2
hmac.SetKey(m_k, m_k.size());
hmac.Update(m_v, m_v.size());
hmac.TruncatedFinal(m_v, m_v.size());
// Step 3
if ((inlen1 | inlen2 | inlen3) == 0)
return;
// Step 4
hmac.SetKey(m_k, m_k.size());
hmac.Update(m_v, m_v.size());
hmac.Update(&one, 1);
if (input1 && inlen1)
hmac.Update(input1, inlen1);
if (input2 && inlen2)
hmac.Update(input2, inlen2);
if (input3 && inlen3)
hmac.Update(input3, inlen3);
hmac.TruncatedFinal(m_k, m_k.size());
// Step 5
hmac.SetKey(m_k, m_k.size());
hmac.Update(m_v, m_v.size());
hmac.TruncatedFinal(m_v, m_v.size());
}
NAMESPACE_END
#endif // CRYPTOPP_NIST_DRBG_H