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Add ability to use Little Endian mode. #235

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Add ability to use Little Endian mode. #235

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14af111
Add ability to use Little Endian mode.
Apr 8, 2020
81c5869
Rename compatibility flag and remove constructor override
Apr 9, 2020
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67 changes: 54 additions & 13 deletions crypto/src/crypto/engines/BlowfishEngine.cs
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Original file line number Diff line number Diff line change
@@ -308,6 +308,8 @@ public sealed class BlowfishEngine

private byte[] workingKey;

private bool useLittleEndian = false;

public BlowfishEngine()
{
S0 = new uint[SBOX_SK];
@@ -317,15 +319,15 @@ public BlowfishEngine()
P = new uint[P_SZ];
}

/**
/**
* initialise a Blowfish cipher.
*
* @param forEncryption whether or not we are for encryption.
* @param parameters the parameters required to set up the cipher.
* @exception ArgumentException if the parameters argument is
* inappropriate.
*/
public void Init(
public void Init(
bool forEncryption,
ICipherParameters parameters)
{
@@ -347,6 +349,8 @@ public bool IsPartialBlockOkay
get { return false; }
}

public bool UseLittleEndian { get => useLittleEndian; set => useLittleEndian = value; }

public int ProcessBlock(
byte[] input,
int inOff,
@@ -505,8 +509,18 @@ private void EncryptBlock(
byte[] dst,
int dstIndex)
{
uint xl = Pack.BE_To_UInt32(src, srcIndex);
uint xr = Pack.BE_To_UInt32(src, srcIndex+4);
uint xl;
uint xr;
if (useLittleEndian)
{
xl = Pack.LE_To_UInt32(src, srcIndex);
xr = Pack.LE_To_UInt32(src, srcIndex + 4);
}
else
{
xl = Pack.BE_To_UInt32(src, srcIndex);
xr = Pack.BE_To_UInt32(src, srcIndex + 4);
}

xl ^= P[0];

@@ -518,8 +532,16 @@ private void EncryptBlock(

xr ^= P[ROUNDS + 1];

Pack.UInt32_To_BE(xr, dst, dstIndex);
Pack.UInt32_To_BE(xl, dst, dstIndex + 4);
if (useLittleEndian)
{
Pack.UInt32_To_LE(xr, dst, dstIndex);
Pack.UInt32_To_LE(xl, dst, dstIndex + 4);
}
else
{
Pack.UInt32_To_BE(xr, dst, dstIndex);
Pack.UInt32_To_BE(xl, dst, dstIndex + 4);
}
}

/**
@@ -533,10 +555,21 @@ private void DecryptBlock(
byte[] dst,
int dstIndex)
{
uint xl = Pack.BE_To_UInt32(src, srcIndex);
uint xr = Pack.BE_To_UInt32(src, srcIndex + 4);

xl ^= P[ROUNDS + 1];
uint xl;
uint xr;

if (useLittleEndian)
{
xl = Pack.LE_To_UInt32(src, srcIndex);
xr = Pack.LE_To_UInt32(src, srcIndex + 4);
}
else
{
xl = Pack.BE_To_UInt32(src, srcIndex);
xr = Pack.BE_To_UInt32(src, srcIndex + 4);
}

xl ^= P[ROUNDS + 1];

for (int i = ROUNDS; i > 0 ; i -= 2)
{
@@ -546,8 +579,16 @@ private void DecryptBlock(

xr ^= P[0];

Pack.UInt32_To_BE(xr, dst, dstIndex);
Pack.UInt32_To_BE(xl, dst, dstIndex + 4);
}
if (useLittleEndian)
{
Pack.UInt32_To_LE(xr, dst, dstIndex);
Pack.UInt32_To_LE(xl, dst, dstIndex + 4);
}
else
{
Pack.UInt32_To_BE(xr, dst, dstIndex);
Pack.UInt32_To_BE(xl, dst, dstIndex + 4);
}
}
}
}