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add minimum iteration time option

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weidai 2004-04-08 01:57:33 +00:00
parent 6569b7fe0b
commit ea022976c4
2 changed files with 72 additions and 21 deletions
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91
pwdbased.h
View File

@ -5,14 +5,20 @@
#include "cryptlib.h" #include "cryptlib.h"
#include "hmac.h" #include "hmac.h"
#include "hrtimer.h"
NAMESPACE_BEGIN(CryptoPP) NAMESPACE_BEGIN(CryptoPP)
//! abstract base class for password based key derivation function
class PasswordBasedKeyDerivationFunction class PasswordBasedKeyDerivationFunction
{ {
public: public:
virtual unsigned int MaxDerivedKeyLength() const =0; virtual unsigned int MaxDerivedKeyLength() const =0;
virtual void GeneralDeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations) const =0; virtual bool UsesPurposeByte() const =0;
//! derive key from password
/*! If timeInSeconds != 0, will iterate until time elapsed, as measured by ThreadUserTimer
Returns actual iteration count, which is equal to iterations if timeInSeconds == 0, and not less than iterations otherwise. */
virtual unsigned int DeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations, double timeInSeconds=0) const =0;
}; };
//! PBKDF1 from PKCS #5, T should be a HashTransformation class //! PBKDF1 from PKCS #5, T should be a HashTransformation class
@ -21,10 +27,9 @@ class PKCS5_PBKDF1 : public PasswordBasedKeyDerivationFunction
{ {
public: public:
unsigned int MaxDerivedKeyLength() const {return T::DIGESTSIZE;} unsigned int MaxDerivedKeyLength() const {return T::DIGESTSIZE;}
bool UsesPurposeByte() const {return false;}
// PKCS #5 says PBKDF1 should only take 8-byte salts. This implementation allows salts of any length. // PKCS #5 says PBKDF1 should only take 8-byte salts. This implementation allows salts of any length.
void GeneralDeriveKey(byte *derived, unsigned int derivedLen, byte ignored, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations) const unsigned int DeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations, double timeInSeconds=0) const;
{DeriveKey(derived, derivedLen, password, passwordLen, salt, saltLen, iterations);}
void DeriveKey(byte *derived, unsigned int derivedLen, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen=8, unsigned int iterations=1000) const;
}; };
//! PBKDF2 from PKCS #5, T should be a HashTransformation class //! PBKDF2 from PKCS #5, T should be a HashTransformation class
@ -33,9 +38,8 @@ class PKCS5_PBKDF2_HMAC : public PasswordBasedKeyDerivationFunction
{ {
public: public:
unsigned int MaxDerivedKeyLength() const {return 0xffffffffU;} // should multiply by T::DIGESTSIZE, but gets overflow that way unsigned int MaxDerivedKeyLength() const {return 0xffffffffU;} // should multiply by T::DIGESTSIZE, but gets overflow that way
void GeneralDeriveKey(byte *derived, unsigned int derivedLen, byte ignored, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations) const bool UsesPurposeByte() const {return false;}
{DeriveKey(derived, derivedLen, password, passwordLen, salt, saltLen, iterations);} unsigned int DeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations, double timeInSeconds=0) const;
void DeriveKey(byte *derived, unsigned int derivedLen, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations=1000) const;
}; };
/* /*
@ -49,10 +53,13 @@ public:
*/ */
template <class T> template <class T>
void PKCS5_PBKDF1<T>::DeriveKey(byte *derived, unsigned int derivedLen, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations) const unsigned int PKCS5_PBKDF1<T>::DeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations, double timeInSeconds) const
{ {
assert(derivedLen <= MaxDerivedKeyLength()); assert(derivedLen <= MaxDerivedKeyLength());
assert(iterations > 0); assert(iterations > 0 || timeInSeconds > 0);
if (!iterations)
iterations = 1;
T hash; T hash;
hash.Update(password, passwordLen); hash.Update(password, passwordLen);
@ -61,20 +68,31 @@ void PKCS5_PBKDF1<T>::DeriveKey(byte *derived, unsigned int derivedLen, const by
SecByteBlock buffer(hash.DigestSize()); SecByteBlock buffer(hash.DigestSize());
hash.Final(buffer); hash.Final(buffer);
for (unsigned int i=1; i<iterations; i++) unsigned int i;
ThreadUserTimer timer;
if (timeInSeconds)
timer.StartTimer();
for (i=1; i<iterations || (timeInSeconds && (i%128!=0 || timer.ElapsedTimeAsDouble() < timeInSeconds)) : ; i++)
hash.CalculateDigest(buffer, buffer, buffer.size()); hash.CalculateDigest(buffer, buffer, buffer.size());
memcpy(derived, buffer, derivedLen); memcpy(derived, buffer, derivedLen);
return i;
} }
template <class T> template <class T>
void PKCS5_PBKDF2_HMAC<T>::DeriveKey(byte *derived, unsigned int derivedLen, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations) const unsigned int PKCS5_PBKDF2_HMAC<T>::DeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations, double timeInSeconds) const
{ {
assert(derivedLen <= MaxDerivedKeyLength()); assert(derivedLen <= MaxDerivedKeyLength());
assert(iterations > 0); assert(iterations > 0 || timeInSeconds > 0);
if (!iterations)
iterations = 1;
HMAC<T> hmac(password, passwordLen); HMAC<T> hmac(password, passwordLen);
SecByteBlock buffer(hmac.DigestSize()); SecByteBlock buffer(hmac.DigestSize());
ThreadUserTimer timer;
unsigned int i=1; unsigned int i=1;
while (derivedLen > 0) while (derivedLen > 0)
@ -91,16 +109,30 @@ void PKCS5_PBKDF2_HMAC<T>::DeriveKey(byte *derived, unsigned int derivedLen, con
unsigned int segmentLen = STDMIN(derivedLen, (unsigned int)buffer.size()); unsigned int segmentLen = STDMIN(derivedLen, (unsigned int)buffer.size());
memcpy(derived, buffer, segmentLen); memcpy(derived, buffer, segmentLen);
for (j=1; j<iterations; j++) if (timeInSeconds)
{
timeInSeconds = timeInSeconds / ((derivedLen + buffer.size() - 1) / buffer.size());
timer.StartTimer();
}
for (j=1; j<iterations || (timeInSeconds && (j%128!=0 || timer.ElapsedTimeAsDouble() < timeInSeconds)); j++)
{ {
hmac.CalculateDigest(buffer, buffer, buffer.size()); hmac.CalculateDigest(buffer, buffer, buffer.size());
xorbuf(derived, buffer, segmentLen); xorbuf(derived, buffer, segmentLen);
} }
if (timeInSeconds)
{
iterations = j;
timeInSeconds = 0;
}
derived += segmentLen; derived += segmentLen;
derivedLen -= segmentLen; derivedLen -= segmentLen;
i++; i++;
} }
return iterations;
} }
//! PBKDF from PKCS #12, appendix B, T should be a HashTransformation class //! PBKDF from PKCS #12, appendix B, T should be a HashTransformation class
@ -109,16 +141,18 @@ class PKCS12_PBKDF : public PasswordBasedKeyDerivationFunction
{ {
public: public:
unsigned int MaxDerivedKeyLength() const {return UINT_MAX;} unsigned int MaxDerivedKeyLength() const {return UINT_MAX;}
void GeneralDeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations) const bool UsesPurposeByte() const {return true;}
{DeriveKey(derived, derivedLen, purpose, password, passwordLen, salt, saltLen, iterations);} unsigned int DeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations, double timeInSeconds) const;
void DeriveKey(byte *derived, unsigned int derivedLen, byte ID, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations=1000) const;
}; };
template <class T> template <class T>
void PKCS12_PBKDF<T>::DeriveKey(byte *derived, unsigned int derivedLen, byte ID, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations) const unsigned int PKCS12_PBKDF<T>::DeriveKey(byte *derived, unsigned int derivedLen, byte purpose, const byte *password, unsigned int passwordLen, const byte *salt, unsigned int saltLen, unsigned int iterations, double timeInSeconds) const
{ {
assert(derivedLen <= MaxDerivedKeyLength()); assert(derivedLen <= MaxDerivedKeyLength());
assert(iterations > 0); assert(iterations > 0 || timeInSeconds > 0);
if (!iterations)
iterations = 1;
const unsigned int v = T::BLOCKSIZE; // v is in bytes rather than bits as in PKCS #12 const unsigned int v = T::BLOCKSIZE; // v is in bytes rather than bits as in PKCS #12
const unsigned int DLen = v, SLen = RoundUpToMultipleOf(saltLen, v); const unsigned int DLen = v, SLen = RoundUpToMultipleOf(saltLen, v);
@ -126,7 +160,7 @@ void PKCS12_PBKDF<T>::DeriveKey(byte *derived, unsigned int derivedLen, byte ID,
SecByteBlock buffer(DLen + SLen + PLen); SecByteBlock buffer(DLen + SLen + PLen);
byte *D = buffer, *S = buffer+DLen, *P = buffer+DLen+SLen, *I = S; byte *D = buffer, *S = buffer+DLen, *P = buffer+DLen+SLen, *I = S;
memset(D, ID, DLen); memset(D, purpose, DLen);
unsigned int i; unsigned int i;
for (i=0; i<SLen; i++) for (i=0; i<SLen; i++)
S[i] = salt[i % saltLen]; S[i] = salt[i % saltLen];
@ -136,12 +170,27 @@ void PKCS12_PBKDF<T>::DeriveKey(byte *derived, unsigned int derivedLen, byte ID,
T hash; T hash;
SecByteBlock Ai(T::DIGESTSIZE), B(v); SecByteBlock Ai(T::DIGESTSIZE), B(v);
ThreadUserTimer timer;
while (derivedLen > 0) while (derivedLen > 0)
{ {
hash.CalculateDigest(Ai, buffer, buffer.size()); hash.CalculateDigest(Ai, buffer, buffer.size());
for (i=1; i<iterations; i++)
if (timeInSeconds)
{
timeInSeconds = timeInSeconds / ((derivedLen + Ai.size() - 1) / Ai.size());
timer.StartTimer();
}
for (i=1; i<iterations || (timeInSeconds && (i%128!=0 || timer.ElapsedTimeAsDouble() < timeInSeconds)); i++)
hash.CalculateDigest(Ai, Ai, Ai.size()); hash.CalculateDigest(Ai, Ai, Ai.size());
if (timeInSeconds)
{
iterations = i;
timeInSeconds = 0;
}
for (i=0; i<B.size(); i++) for (i=0; i<B.size(); i++)
B[i] = Ai[i % Ai.size()]; B[i] = Ai[i % Ai.size()];
@ -155,6 +204,8 @@ void PKCS12_PBKDF<T>::DeriveKey(byte *derived, unsigned int derivedLen, byte ID,
derived += segmentLen; derived += segmentLen;
derivedLen -= segmentLen; derivedLen -= segmentLen;
} }
return iterations;
} }
NAMESPACE_END NAMESPACE_END

2
validat3.cpp
View File

@ -748,7 +748,7 @@ bool TestPBKDF(PasswordBasedKeyDerivationFunction &pbkdf, const PBKDF_TestTuple
StringSource(tuple.hexDerivedKey, true, new HexDecoder(new StringSink(derivedKey))); StringSource(tuple.hexDerivedKey, true, new HexDecoder(new StringSink(derivedKey)));
SecByteBlock derived(derivedKey.size()); SecByteBlock derived(derivedKey.size());
pbkdf.GeneralDeriveKey(derived, derived.size(), tuple.purpose, (byte *)password.data(), password.size(), (byte *)salt.data(), salt.size(), tuple.iterations); pbkdf.DeriveKey(derived, derived.size(), tuple.purpose, (byte *)password.data(), password.size(), (byte *)salt.data(), salt.size(), tuple.iterations);
bool fail = memcmp(derived, derivedKey.data(), derived.size()) != 0; bool fail = memcmp(derived, derivedKey.data(), derived.size()) != 0;
pass = pass && !fail; pass = pass && !fail;