Org.BouncyCastle.Crypto.Engines.RC2Engine.GenerateWorkingKey C# (CSharp) Method

        private int[] GenerateWorkingKey(
            byte[]      key,
            int         bits)
        {
            int     x;
            int[]   xKey = new int[128];

            for (int i = 0; i != key.Length; i++)
            {
                xKey[i] = key[i] & 0xff;
            }

            // Phase 1: Expand input key to 128 bytes
            int len = key.Length;

            if (len < 128)
            {
                int     index = 0;

                x = xKey[len - 1];

                do
                {
                    x = piTable[(x + xKey[index++]) & 255] & 0xff;
                    xKey[len++] = x;
                }
                while (len < 128);
            }

            // Phase 2 - reduce effective key size to "bits"
            len = (bits + 7) >> 3;
            x = piTable[xKey[128 - len] & (255 >> (7 & -bits))] & 0xff;
            xKey[128 - len] = x;

            for (int i = 128 - len - 1; i >= 0; i--)
            {
                    x = piTable[x ^ xKey[i + len]] & 0xff;
                    xKey[i] = x;
            }

            // Phase 3 - copy to newKey in little-endian order
            int[] newKey = new int[64];

            for (int i = 0; i != newKey.Length; i++)
            {
                newKey[i] = (xKey[2 * i] + (xKey[2 * i + 1] << 8));
            }

            return newKey;
        }