// Encryption key setup.
	var i int
	nk := len(key) / 4
	for i = 0; i < nk; i++ {
		enc[i] = byteorder.BeUint32(key[4*i:])
	}
	for ; i < len(enc); i++ {
		t := enc[i-1]
		if i%nk == 0 {
			t = subw(rotw(t)) ^ (uint32(powx[i/nk-1]) << 24)
		} else if nk > 6 && i%nk == 4 {
			t = subw(t)
		}
		enc[i] = enc[i-nk] ^ t
	}

	// Derive decryption key from encryption key.

	ksContext = append(ksContext, infoHash...)

	secret := kdf.LabeledExtract(suiteID, sharedSecret, "secret", nil)

	key := kdf.LabeledExpand(suiteID, secret, "key", ksContext, uint16(aeadInfo.keySize) /* Nk - key size for AEAD */)
	baseNonce := kdf.LabeledExpand(suiteID, secret, "base_nonce", ksContext, uint16(aeadInfo.nonceSize) /* Nn - nonce size for AEAD */)

00000300  45 66 cb 45 75 9c da 92  cc bb 4a a5 ae 41 8c f8  |Ef.Eu.....J..A..|
00000310  9b e7 06 73 88 9f f9 7d  95 ce 74 a6 05 e9 38 a5  |...s...}..t...8.|
00000320  26 4b b2 26 31 5c e9 f9  a8 f8 6e 6b 05 e4 39 b5  |&K.&1\....nk..9.|
00000330  fe b1 b1 cd 40 23 e9 68  f3 9c ed 91 71 d3 0b c5  |....@#.h....q...|
00000340  91 c5 b2 91 69 a9 4b 2c  a7 0c 24 d6 a9 e7 74 89  |....i.K,..$...t.|

00000380  77 99 2f 90 21 a1 5f cc  9f 08 e2 75 44 2f bf 58  |w./.!._....uD/.X|
00000390  70 f2 95 b2 13 20 f3 ed  51 de e8 02 c6 ca 44 57  |p.... ..Q.....DW|
000003a0  eb 0b 9f 3e 61 f1 1a 6e  6b 13 f5 14 f3 43 19 f6  |...>a..nk....C..|
000003b0  7d 46 3a 73 49 2f fd 83  c3 68 c7 ba b4 e8 17 03  |}F:sI/...h......|
000003c0  03 00 35 67 2b 2b 9b f0  f3 d9 09 c4 01 20 ea 22  |..5g++....... ."|

00000190  f0 5d 83 9d c9 e2 b3 f8  e4 a3 a5 57 5d ca 30 74  |.].........W].0t|
000001a0  a6 1b c7 51 50 05 5f 7e  93 71 1a 8d fc 04 d6 fe  |...QP._~.q......|
000001b0  4e 4b 95 54 18 43 19 4d  d2 dc 81 a8 94 76 7e 23  |NK.T.C.M.....v~#|
000001c0  56 8c 86 f9 15 d2 a8 0c  48 4e 0e 81 df e0 31 52  |V.......HN....1R|
000001d0  c9 2e b4 39 f3 cf ae e2  29 72 01 ed 34 4f 09 ce  |...9....)r..4O..|