From b21162cf8e06f40baa1f58be6a8c17435cebc34d Mon Sep 17 00:00:00 2001 From: weidai Date: Fri, 4 Oct 2002 17:31:41 +0000 Subject: Initial revision git-svn-id: svn://svn.code.sf.net/p/cryptopp/code/trunk/c5@2 57ff6487-cd31-0410-9ec3-f628ee90f5f0 --- default.cpp | 258 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 258 insertions(+) create mode 100644 default.cpp (limited to 'default.cpp') diff --git a/default.cpp b/default.cpp new file mode 100644 index 0000000..ca99414 --- /dev/null +++ b/default.cpp @@ -0,0 +1,258 @@ +// default.cpp - written and placed in the public domain by Wei Dai + +#include "pch.h" +#include "default.h" +#include "queue.h" +#include +#include + +NAMESPACE_BEGIN(CryptoPP) + +static const unsigned int MASH_ITERATIONS = 200; +static const unsigned int SALTLENGTH = 8; +static const unsigned int BLOCKSIZE = Default_BlockCipher::Encryption::BLOCKSIZE; +static const unsigned int KEYLENGTH = Default_BlockCipher::Encryption::DEFAULT_KEYLENGTH; + +// The purpose of this function Mash() is to take an arbitrary length input +// string and *deterministicly* produce an arbitrary length output string such +// that (1) it looks random, (2) no information about the input is +// deducible from it, and (3) it contains as much entropy as it can hold, or +// the amount of entropy in the input string, whichever is smaller. + +static void Mash(const byte *in, word16 inLen, byte *out, word16 outLen, int iterations) +{ + unsigned int bufSize = (outLen-1+DefaultHashModule::DIGESTSIZE-((outLen-1)%DefaultHashModule::DIGESTSIZE)); + + // ASSERT: bufSize == (the smallest multiple of DIGESTSIZE that is >= outLen) + + byte b[2]; + SecByteBlock buf(bufSize); + SecByteBlock outBuf(bufSize); + DefaultHashModule hash; + + unsigned int i; + for(i=0; i> 8; + b[1] = (byte) i; + hash.Update(b, 2); + hash.Update(in, inLen); + hash.Final(outBuf+i); + } + + while (iterations-- > 1) + { + memcpy(buf, outBuf, bufSize); + for (i=0; i> 8; + b[1] = (byte) i; + hash.Update(b, 2); + hash.Update(buf, bufSize); + hash.Final(outBuf+i); + } + } + + memcpy(out, outBuf, outLen); +} + +static void GenerateKeyIV(const byte *passphrase, unsigned int passphraseLength, const byte *salt, unsigned int saltLength, byte *key, byte *IV) +{ + SecByteBlock temp(passphraseLength+saltLength); + memcpy(temp, passphrase, passphraseLength); + memcpy(temp+passphraseLength, salt, saltLength); + SecByteBlock keyIV(KEYLENGTH+BLOCKSIZE); + Mash(temp, passphraseLength + saltLength, keyIV, KEYLENGTH+BLOCKSIZE, MASH_ITERATIONS); + memcpy(key, keyIV, KEYLENGTH); + memcpy(IV, keyIV+KEYLENGTH, BLOCKSIZE); +} + +// ******************************************************** + +DefaultEncryptor::DefaultEncryptor(const char *passphrase, BufferedTransformation *attachment) + : ProxyFilter(NULL, 0, 0, attachment), m_passphrase((const byte *)passphrase, strlen(passphrase)) +{ +} + +DefaultEncryptor::DefaultEncryptor(const byte *passphrase, unsigned int passphraseLength, BufferedTransformation *attachment) + : ProxyFilter(NULL, 0, 0, attachment), m_passphrase(passphrase, passphraseLength) +{ +} + + +void DefaultEncryptor::FirstPut(const byte *) +{ + // VC60 workaround: __LINE__ expansion bug + CRYPTOPP_COMPILE_ASSERT_INSTANCE(SALTLENGTH <= DefaultHashModule::DIGESTSIZE, 1); + CRYPTOPP_COMPILE_ASSERT_INSTANCE(BLOCKSIZE <= DefaultHashModule::DIGESTSIZE, 2); + + SecByteBlock salt(DefaultHashModule::DIGESTSIZE), keyCheck(DefaultHashModule::DIGESTSIZE); + DefaultHashModule hash; + + // use hash(passphrase | time | clock) as salt + hash.Update(m_passphrase, m_passphrase.size()); + time_t t=time(0); + hash.Update((byte *)&t, sizeof(t)); + clock_t c=clock(); + hash.Update((byte *)&c, sizeof(c)); + hash.Final(salt); + + // use hash(passphrase | salt) as key check + hash.Update(m_passphrase, m_passphrase.size()); + hash.Update(salt, SALTLENGTH); + hash.Final(keyCheck); + + AttachedTransformation()->Put(salt, SALTLENGTH); + + // mash passphrase and salt together into key and IV + SecByteBlock key(KEYLENGTH); + SecByteBlock IV(BLOCKSIZE); + GenerateKeyIV(m_passphrase, m_passphrase.size(), salt, SALTLENGTH, key, IV); + + m_cipher.SetKeyWithIV(key, key.size(), IV); + SetFilter(new StreamTransformationFilter(m_cipher)); + + m_filter->Put(keyCheck, BLOCKSIZE); +} + +void DefaultEncryptor::LastPut(const byte *inString, unsigned int length) +{ + m_filter->MessageEnd(); +} + +// ******************************************************** + +DefaultDecryptor::DefaultDecryptor(const char *p, BufferedTransformation *attachment, bool throwException) + : ProxyFilter(NULL, SALTLENGTH+BLOCKSIZE, 0, attachment) + , m_state(WAITING_FOR_KEYCHECK) + , m_passphrase((const byte *)p, strlen(p)) + , m_throwException(throwException) +{ +} + +DefaultDecryptor::DefaultDecryptor(const byte *passphrase, unsigned int passphraseLength, BufferedTransformation *attachment, bool throwException) + : ProxyFilter(NULL, SALTLENGTH+BLOCKSIZE, 0, attachment) + , m_state(WAITING_FOR_KEYCHECK) + , m_passphrase(passphrase, passphraseLength) + , m_throwException(throwException) +{ +} + +void DefaultDecryptor::FirstPut(const byte *inString) +{ + CheckKey(inString, inString+SALTLENGTH); +} + +void DefaultDecryptor::LastPut(const byte *inString, unsigned int length) +{ + if (m_filter.get() == NULL) + { + m_state = KEY_BAD; + if (m_throwException) + throw KeyBadErr(); + } + else + { + m_filter->MessageEnd(); + m_state = WAITING_FOR_KEYCHECK; + } +} + +void DefaultDecryptor::CheckKey(const byte *salt, const byte *keyCheck) +{ + SecByteBlock check(STDMAX((unsigned int)2*BLOCKSIZE, (unsigned int)DefaultHashModule::DIGESTSIZE)); + + DefaultHashModule hash; + hash.Update(m_passphrase, m_passphrase.size()); + hash.Update(salt, SALTLENGTH); + hash.Final(check); + + SecByteBlock key(KEYLENGTH); + SecByteBlock IV(BLOCKSIZE); + GenerateKeyIV(m_passphrase, m_passphrase.size(), salt, SALTLENGTH, key, IV); + + m_cipher.SetKeyWithIV(key, key.size(), IV); + std::auto_ptr decryptor(new StreamTransformationFilter(m_cipher)); + + decryptor->Put(keyCheck, BLOCKSIZE); + decryptor->ForceNextPut(); + decryptor->Get(check+BLOCKSIZE, BLOCKSIZE); + + SetFilter(decryptor.release()); + + if (memcmp(check, check+BLOCKSIZE, BLOCKSIZE)) + { + m_state = KEY_BAD; + if (m_throwException) + throw KeyBadErr(); + } + else + m_state = KEY_GOOD; +} + +// ******************************************************** + +static DefaultMAC * NewDefaultEncryptorMAC(const byte *passphrase, unsigned int passphraseLength) +{ + unsigned int macKeyLength = DefaultMAC::StaticGetValidKeyLength(16); + SecByteBlock macKey(macKeyLength); + // since the MAC is encrypted there is no reason to mash the passphrase for many iterations + Mash(passphrase, passphraseLength, macKey, macKeyLength, 1); + return new DefaultMAC(macKey, macKeyLength); +} + +DefaultEncryptorWithMAC::DefaultEncryptorWithMAC(const char *passphrase, BufferedTransformation *attachment) + : ProxyFilter(NULL, 0, 0, attachment) + , m_mac(NewDefaultEncryptorMAC((const byte *)passphrase, strlen(passphrase))) +{ + SetFilter(new HashFilter(*m_mac, new DefaultEncryptor(passphrase), true)); +} + +DefaultEncryptorWithMAC::DefaultEncryptorWithMAC(const byte *passphrase, unsigned int passphraseLength, BufferedTransformation *attachment) + : ProxyFilter(NULL, 0, 0, attachment) + , m_mac(NewDefaultEncryptorMAC(passphrase, passphraseLength)) +{ + SetFilter(new HashFilter(*m_mac, new DefaultEncryptor(passphrase, passphraseLength), true)); +} + +void DefaultEncryptorWithMAC::LastPut(const byte *inString, unsigned int length) +{ + m_filter->MessageEnd(); +} + +// ******************************************************** + +DefaultDecryptorWithMAC::DefaultDecryptorWithMAC(const char *passphrase, BufferedTransformation *attachment, bool throwException) + : ProxyFilter(NULL, 0, 0, attachment) + , m_mac(NewDefaultEncryptorMAC((const byte *)passphrase, strlen(passphrase))) + , m_throwException(throwException) +{ + SetFilter(new DefaultDecryptor(passphrase, m_hashVerifier=new HashVerifier(*m_mac, NULL, HashVerifier::PUT_MESSAGE), throwException)); +} + +DefaultDecryptorWithMAC::DefaultDecryptorWithMAC(const byte *passphrase, unsigned int passphraseLength, BufferedTransformation *attachment, bool throwException) + : ProxyFilter(NULL, 0, 0, attachment) + , m_mac(NewDefaultEncryptorMAC(passphrase, passphraseLength)) + , m_throwException(throwException) +{ + SetFilter(new DefaultDecryptor(passphrase, passphraseLength, m_hashVerifier=new HashVerifier(*m_mac, NULL, HashVerifier::PUT_MESSAGE), throwException)); +} + +DefaultDecryptor::State DefaultDecryptorWithMAC::CurrentState() const +{ + return static_cast(m_filter.get())->CurrentState(); +} + +bool DefaultDecryptorWithMAC::CheckLastMAC() const +{ + return m_hashVerifier->GetLastResult(); +} + +void DefaultDecryptorWithMAC::LastPut(const byte *inString, unsigned int length) +{ + m_filter->MessageEnd(); + if (m_throwException && !CheckLastMAC()) + throw MACBadErr(); +} + +NAMESPACE_END -- cgit v1.2.1