static public void Transform(Span <byte> c, ReadOnlySpan <byte> n, ReadOnlySpan <byte> k)
{
if (c.IsEmpty)
{
return;
}
var input = new byte[16];
var block = new byte[64];
var kcopy = k.ToArray();
try
{
for (int i = 0; i < 8; i++)
{
input[i] = n[i];
}
while (c.Length >= 64)
{
Salsa20.Transform(block, input, kcopy, null);
block.CopyTo(c);
uint u = 1;
for (int i = 8; i < 16; i++)
{
u += (uint)input[i];
input[i] = (byte)u;
u >>= 8;
}
c = c.Slice(64);
}
if (c.Length != 0)
{
Salsa20.Transform(block, input, kcopy, null);
for (int i = 0; i < c.Length; i++)
{
c[i] = block[i];
}
}
}
finally
{
input.Clear();
block.Clear();
kcopy.Clear();
}
}
public static void Transform(Span <byte> c, ReadOnlySpan <byte> m, ReadOnlySpan <byte> n, ReadOnlySpan <byte> k,
UInt64 ic = 0)
{
if (m.Length == 0)
{
return;
}
var input = new byte[16];
var block = new byte[64];
var kcopy = k.Slice(0, 32).ToArray();
try
{
UInt32 u;
n.Slice(0, 8).CopyTo(input);
for (int i = 8; i < 16; i++)
{
input[i] = (byte)(ic & 0xff);
ic >>= 8;
}
int mlen = m.Length;
while (mlen >= 64)
{
Salsa20.Transform(block, input, kcopy, null);
for (int i = 0; i < 64; i++)
{
c[i] = (byte)(m[i] ^ block[i]);
}
u = 1;
for (int i = 8; i < 16; i++)
{
u += input[i];
input[i] = (byte)u;
u >>= 8;
}
mlen -= 64;
c = c.Slice(64);
m = m.Slice(64);
}
if (mlen != 0)
{
Salsa20.Transform(block, input, kcopy, null);
for (int i = 0; i < mlen; i++)
{
c[i] = (byte)(m[i] ^ block[i]);
}
}
}
finally
{
input.Clear();
block.Clear();
kcopy.Clear();
}
}
