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// sapphire.cpp -- modified by Wei Dai from:
/* sapphire.cpp -- the Saphire II stream cipher class.
Dedicated to the Public Domain the author and inventor:
(Michael Paul Johnson). This code comes with no warranty.
Use it at your own risk.
Ported from the Pascal implementation of the Sapphire Stream
Cipher 9 December 1994.
Added hash pre- and post-processing 27 December 1994.
Modified initialization to make index variables key dependent,
made the output function more resistant to cryptanalysis,
and renamed to Sapphire II 2 January 1995
*/
#include "pch.h"
#include "sapphire.h"
NAMESPACE_BEGIN(CryptoPP)
byte SapphireBase::keyrand(unsigned int limit,
const byte *user_key,
byte keysize,
byte *rsum,
unsigned *keypos)
{
unsigned u, // Value from 0 to limit to return.
retry_limiter, // No infinite loops allowed.
mask; // Select just enough bits.
retry_limiter = 0;
mask = 1; // Fill mask with enough bits to cover
while (mask < limit) // the desired range.
mask = (mask << 1) + 1;
do
{
*rsum = cards[*rsum] + user_key[(*keypos)++];
if (*keypos >= keysize)
{
*keypos = 0; // Recycle the user key.
*rsum += keysize; // key "aaaa" != key "aaaaaaaa"
}
u = mask & *rsum;
if (++retry_limiter > 11)
u %= limit; // Prevent very rare long loops.
}
while (u > limit);
return u;
}
SapphireBase::SapphireBase()
: cards(256)
{
}
SapphireBase::SapphireBase(const byte *key, unsigned int keysize)
: cards(256)
{
assert(keysize < 256);
// Key size may be up to 256 bytes.
// Pass phrases may be used directly, with longer length
// compensating for the low entropy expected in such keys.
// Alternatively, shorter keys hashed from a pass phrase or
// generated randomly may be used. For random keys, lengths
// of from 4 to 16 bytes are recommended, depending on how
// secure you want this to be.
int i;
byte rsum;
unsigned keypos;
// Start with cards all in order, one of each.
for (i=0;i<256;i++)
cards[i] = i;
// Swap the card at each position with some other card.
keypos = 0; // Start with first byte of user key.
rsum = 0;
for (i=255;i;i--)
std::swap(cards[i], cards[keyrand(i, key, keysize, &rsum, &keypos)]);
// Initialize the indices and data dependencies.
// Indices are set to different values instead of all 0
// to reduce what is known about the state of the cards
// when the first byte is emitted.
rotor = cards[1];
ratchet = cards[3];
avalanche = cards[5];
last_plain = cards[7];
last_cipher = cards[rsum];
rsum = 0;
keypos = 0;
}
SapphireBase::~SapphireBase()
{
rotor = ratchet = avalanche = last_plain = last_cipher = 0;
}
void SapphireEncryption::ProcessString(byte *outString, const byte *inString, unsigned int length)
{
while(length--)
*outString++ = SapphireEncryption::ProcessByte(*inString++);
}
void SapphireEncryption::ProcessString(byte *inoutString, unsigned int length)
{
while(length--)
{
*inoutString = SapphireEncryption::ProcessByte(*inoutString);
inoutString++;
}
}
void SapphireDecryption::ProcessString(byte *outString, const byte *inString, unsigned int length)
{
while(length--)
*outString++ = SapphireDecryption::ProcessByte(*inString++);
}
void SapphireDecryption::ProcessString(byte *inoutString, unsigned int length)
{
while(length--)
{
*inoutString = SapphireDecryption::ProcessByte(*inoutString);
inoutString++;
}
}
SapphireHash::SapphireHash(unsigned int hashLength)
: hashLength(hashLength)
{
Init();
}
void SapphireHash::Init()
{
// This function is used to initialize non-keyed hash
// computation.
int i, j;
// Initialize the indices and data dependencies.
rotor = 1;
ratchet = 3;
avalanche = 5;
last_plain = 7;
last_cipher = 11;
// Start with cards all in inverse order.
for (i=0, j=255;i<256;i++,j--)
cards[i] = (byte) j;
}
void SapphireHash::Update(const byte *input, unsigned int length)
{
while(length--)
SapphireEncryption::ProcessByte(*input++);
}
void SapphireHash::TruncatedFinal(byte *hash, unsigned int size)
{
ThrowIfInvalidTruncatedSize(size);
for (int i=255; i>=0; i--)
ProcessByte((byte) i);
for (unsigned int j=0; j<size; j++)
hash[j] = ProcessByte(0);
Init();
}
NAMESPACE_END
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