blowfish forklaring

Hej hej.... ja her er problemet:


1. KEY EXPANSION converts a key of up to 448 bytes into several subkey 32-bit arrays: the permutation-array, denoted Pi (i=1,...18); and the string-array, denoted Si,j (i=1,...4) and (j=0,...255).
2. DATA ENCRYPTION consists of a FEISTEL FUNCTION, F(), iterated for 16 rounds.
To encrypt, divide the initial plaintext into a left and right half, 32 bits apiece, denoted L0 and R0. Then for each i, i=1,...16:
let Li be set equal to Li-1 ^ Pi; let Ri be set equal to F(Li) ^ Pi; then swap Li and Ri.
Finally, swap Li and Ri (i.e., undo the 16th swap). Then:
Let Rfinal be set equal to R16^P17; Let Lfinal be set equal to L16^P18;
Finally, rejoin the right and left halves, denoted Lfinal and Rfinal.
      Decryption is the same as encryption, except that P1,... P18 are used in reverse order.
      Subkeys are calculated as follows:

1. Initialize P'1,... P'18, and then S'1,0,... S'4,255, in order, using the hexadecimal expansion of pi.
2. Obtain the secret-permutation array, P1,... P18, by letting Pi be set equal to P'i ^ Ki.
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Er der nogen der kan oversætte eller rettere forklare?
På forhånd tak!