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BLOWFISH-Verschlüsselung
| Lizenz: | Erster Autor: | Letzte Bearbeitung: |
| LGPL |  ukimiku |  27.06.2015 |
' ******************************************************************************************
' * BLOWFISH-Verschlüsselung *
' * Blowfish ist eine symmetrische Blockcipher-Verschlüsselung. *
' * "Symmetrisch" bedeutet, man braucht zum Ver- und Entschlüsseln denselben *
' * Schlüssel (einen String). *
' * *
' ' Gebrauch: *
' ' Um einen neuen Schlüssel wirksam werden zu lassen, egal ob zum Ver- *
' * oder Entschlüsseln eines Textes, muss zuvor Initialsiere_Blowfish(schluessel) *
' ' aufgerufen werden. Dann können Texte mit Verschluessele_Blowfish(text, schluessel) *
' * verschlüsselt werden und mit Entschluessele_Blowfish(codetext, schluessel) *
' * wieder entschlüsselt werden. *
' * *
' * Aus einem ASCII-Test erstellt die Verschlüsselung einen doppelt so langen *
' * HEX-String, der sich problemlos per E-Mail etc. übertragen lässt. *
' * *
' * Einschränkungen: *
' * 1) Der Klartext, der verschlüsselt werden soll, muss ein Vielfaches *
' * von 8 Zeichen lang sein. Andernfalls muss er auf ein Vielfaches von *
' * 8 Zeichen aufgefüllt werden. Die überschüssigen Zeichen müssen nach *
' * dem Entschlüsseln wieder entfernt werden. *
' * *
' * geschrieben in Freebasic von Michael Kuyumcu, info-at-noemanetz.de, 2015-06-27 *
' * No copyright. Code kann beliebig verändert werden (auf eigene Gefahr). *
' ' Infos zu Blowfish: https://www.schneier.com/blowfish.html (vom Erfinder) *
' ******************************************************************************************
'
Declare Sub Initialisiere_Blowfish(key As String)
Declare Sub Zuruecksetzen_Blowfish()
Declare function Verschluessele_Blowfish(t As String, passwort As string) As String
Declare Function Entschluessele_Blowfish(t As String, passwort As String) As String
Declare sub BFenc(ByRef ql As ulong, ByRef qr As ulong)
Declare sub BFdec(ByRef ql As ulong, ByRef qr As ulong)
Declare Function Vier_Ascii_in_dezimal(t As string) As ULong
Declare Function Dezimal_in_vier_ASCII(datum As ulong) As String
'************************************
'* BLOWFISH-Daten *
' ***********************************
Dim Shared As String blowfish_lastkey
Dim Shared As ULong Sbox(0 To 3, 0 To 255) = {{3509652390,2564797868,805139163,3491422135,3101798381,1780907670,3128725573,4046225305,614570311,3012652279,134345442,2240740374,1667834072,1901547113,2757295779,4103290238,227898511,1921955416,1904987480,2182433518,2069144605,3260701109,2620446009,720527379,3318853667,677414384,3393288472,3101374703,2390351024,1614419982,1822297739,2954791486,3608508353,3174124327,2024746970,1432378464,3864339955,2857741204,1464375394,1676153920,1439316330,715854006,3033291828,289532110,2706671279,2087905683,3018724369,1668267050,732546397,1947742710,3462151702,2609353502,2950085171,1814351708,2050118529,680887927,999245976,1800124847,3300911131,1713906067,1641548236,4213287313,1216130144,1575780402,4018429277,3917837745,3693486850,3949271944,596196993,3549867205,258830323,2213823033,772490370,2760122372,1774776394,2652871518,566650946,4142492826,1728879713,2882767088,1783734482,3629395816,2517608232,2874225571,1861159788,326777828,3124490320,2130389656,2716951837,967770486,1724537150,2185432712,2364442137,1164943284,2105845187,998989502,3765401048,2244026483,1075463327,1455516326,1322494562,910128902,469688178,1117454909,936433444,3490320968,3675253459,1240580251,122909385,2157517691,634681816,4142456567,3825094682,3061402683,2540495037,79693498,3249098678,1084186820,1583128258,426386531,1761308591,1047286709,322548459,995290223,1845252383,2603652396,3431023940,2942221577,3202600964,3727903485,1712269319,422464435,3234572375,1170764815,3523960633,3117677531,1434042557,442511882,3600875718,1076654713,1738483198,4213154764,2393238008,3677496056,1014306527,4251020053,793779912,2902807211,842905082,4246964064,1395751752,1040244610,2656851899,3396308128,445077038,3742853595,3577915638,679411651,2892444358,2354009459,1767581616,3150600392,3791627101,3102740896,284835224,4246832056,1258075500,768725851,2589189241,3069724005,3532540348,1274779536,3789419226,2764799539,1660621633,3471099624,4011903706,913787905,3497959166,737222580,2514213453,2928710040,3937242737,1804850592,3499020752,2949064160,2386320175,2390070455,2415321851,4061277028,2290661394,2416832540,1336762016,1754252060,3520065937,3014181293,791618072,3188594551,3933548030,2332172193,3852520463,3043980520,413987798,3465142937,3030929376,4245938359,2093235073,3534596313,375366246,2157278981,2479649556,555357303,3870105701,2008414854,3344188149,4221384143,3956125452,2067696032,3594591187,2921233993,2428461,544322398,577241275,1471733935,610547355,4027169054,1432588573,1507829418,2025931657,3646575487,545086370,48609733,2200306550,1653985193,298326376,1316178497,3007786442,2064951626,458293330,2589141269,3591329599,3164325604,727753846,2179363840,146436021,1461446943,4069977195,705550613,3059967265,3887724982,4281599278,3313849956,1404054877,2845806497,146425753,1854211946}, _
{1266315497,3048417604,3681880366,3289982499,2909710000,1235738493,2632868024,2414719590,3970600049,1771706367,1449415276,3266420449,422970021,1963543593,2690192192,3826793022,1062508698,1531092325,1804592342,2583117782,2714934279,4024971509,1294809318,4028980673,1289560198,2221992742,1669523910,35572830,157838143,1052438473,1016535060,1802137761,1753167236,1386275462,3080475397,2857371447,1040679964,2145300060,2390574316,1461121720,2956646967,4031777805,4028374788,33600511,2920084762,1018524850,629373528,3691585981,3515945977,2091462646,2486323059,586499841,988145025,935516892,3367335476,2599673255,2839830854,265290510,3972581182,2759138881,3795373465,1005194799,847297441,406762289,1314163512,1332590856,1866599683,4127851711,750260880,613907577,1450815602,3165620655,3734664991,3650291728,3012275730,3704569646,1427272223,778793252,1343938022,2676280711,2052605720,1946737175,3164576444,3914038668,3967478842,3682934266,1661551462,3294938066,4011595847,840292616,3712170807,616741398,312560963,711312465,1351876610,322626781,1910503582,271666773,2175563734,1594956187,70604529,3617834859,1007753275,1495573769,4069517037,2549218298,2663038764,504708206,2263041392,3941167025,2249088522,1514023603,1998579484,1312622330,694541497,2582060303,2151582166,1382467621,776784248,2618340202,3323268794,2497899128,2784771155,503983604,4076293799,907881277,423175695,432175456,1378068232,4145222326,3954048622,3938656102,3820766613,2793130115,2977904593,26017576,3274890735,3194772133,1700274565,1756076034,4006520079,3677328699,720338349,1533947780,354530856,688349552,3973924725,1637815568,332179504,3949051286,53804574,2852348879,3044236432,1282449977,3583942155,3416972820,4006381244,1617046695,2628476075,3002303598,1686838959,431878346,2686675385,1700445008,1080580658,1009431731,832498133,3223435511,2605976345,2271191193,2516031870,1648197032,4164389018,2548247927,300782431,375919233,238389289,3353747414,2531188641,2019080857,1475708069,455242339,2609103871,448939670,3451063019,1395535956,2413381860,1841049896,1491858159,885456874,4264095073,4001119347,1565136089,3898914787,1108368660,540939232,1173283510,2745871338,3681308437,4207628240,3343053890,4016749493,1699691293,1103962373,3625875870,2256883143,3830138730,1031889488,3479347698,1535977030,4236805024,3251091107,2132092099,1774941330,1199868427,1452454533,157007616,2904115357,342012276,595725824,1480756522,206960106,497939518,591360097,863170706,2375253569,3596610801,1814182875,2094937945,3421402208,1082520231,3463918190,2785509508,435703966,3908032597,1641649973,2842273706,3305899714,1510255612,2148256476,2655287854,3276092548,4258621189,236887753,3681803219,274041037,1734335097,3815195456,3317970021,1899903192,1026095262,4050517792,356393447,2410691914,3873677099,3682840055}, _
{3913112168,2491498743,4132185628,2489919796,1091903735,1979897079,3170134830,3567386728,3557303409,857797738,1136121015,1342202287,507115054,2535736646,337727348,3213592640,1301675037,2528481711,1895095763,1721773893,3216771564,62756741,2142006736,835421444,2531993523,1442658625,3659876326,2882144922,676362277,1392781812,170690266,3921047035,1759253602,3611846912,1745797284,664899054,1329594018,3901205900,3045908486,2062866102,2865634940,3543621612,3464012697,1080764994,553557557,3656615353,3996768171,991055499,499776247,1265440854,648242737,3940784050,980351604,3713745714,1749149687,3396870395,4211799374,3640570775,1161844396,3125318951,1431517754,545492359,4268468663,3499529547,1437099964,2702547544,3433638243,2581715763,2787789398,1060185593,1593081372,2418618748,4260947970,69676912,2159744348,86519011,2512459080,3838209314,1220612927,3339683548,133810670,1090789135,1078426020,1569222167,845107691,3583754449,4072456591,1091646820,628848692,1613405280,3757631651,526609435,236106946,48312990,2942717905,3402727701,1797494240,859738849,992217954,4005476642,2243076622,3870952857,3732016268,765654824,3490871365,2511836413,1685915746,3888969200,1414112111,2273134842,3281911079,4080962846,172450625,2569994100,980381355,4109958455,2819808352,2716589560,2568741196,3681446669,3329971472,1835478071,660984891,3704678404,4045999559,3422617507,3040415634,1762651403,1719377915,3470491036,2693910283,3642056355,3138596744,1364962596,2073328063,1983633131,926494387,3423689081,2150032023,4096667949,1749200295,3328846651,309677260,2016342300,1779581495,3079819751,111262694,1274766160,443224088,298511866,1025883608,3806446537,1145181785,168956806,3641502830,3584813610,1689216846,3666258015,3200248200,1692713982,2646376535,4042768518,1618508792,1610833997,3523052358,4130873264,2001055236,3610705100,2202168115,4028541809,2961195399,1006657119,2006996926,3186142756,1430667929,3210227297,1314452623,4074634658,4101304120,2273951170,1399257539,3367210612,3027628629,1190975929,2062231137,2333990788,2221543033,2438960610,1181637006,548689776,2362791313,3372408396,3104550113,3145860560,296247880,1970579870,3078560182,3769228297,1714227617,3291629107,3898220290,166772364,1251581989,493813264,448347421,195405023,2709975567,677966185,3703036547,1463355134,2715995803,1338867538,1343315457,2802222074,2684532164,233230375,2599980071,2000651841,3277868038,1638401717,4028070440,3237316320,6314154,819756386,300326615,590932579,1405279636,3267499572,3150704214,2428286686,3959192993,3461946742,1862657033,1266418056,963775037,2089974820,2263052895,1917689273,448879540,3550394620,3981727096,150775221,3627908307,1303187396,508620638,2975983352,2726630617,1817252668,1876281319,1457606340,908771278,3720792119,3617206836,2455994898,1729034894,1080033504}, _
{976866871,3556439503,2881648439,1522871579,1555064734,1336096578,3548522304,2579274686,3574697629,3205460757,3593280638,3338716283,3079412587,564236357,2993598910,1781952180,1464380207,3163844217,3332601554,1699332808,1393555694,1183702653,3581086237,1288719814,691649499,2847557200,2895455976,3193889540,2717570544,1781354906,1676643554,2592534050,3230253752,1126444790,2770207658,2633158820,2210423226,2615765581,2414155088,3127139286,673620729,2805611233,1269405062,4015350505,3341807571,4149409754,1057255273,2012875353,2162469141,2276492801,2601117357,993977747,3918593370,2654263191,753973209,36408145,2530585658,25011837,3520020182,2088578344,530523599,2918365339,1524020338,1518925132,3760827505,3759777254,1202760957,3985898139,3906192525,674977740,4174734889,2031300136,2019492241,3983892565,4153806404,3822280332,352677332,2297720250,60907813,90501309,3286998549,1016092578,2535922412,2839152426,457141659,509813237,4120667899,652014361,1966332200,2975202805,55981186,2327461051,676427537,3255491064,2882294119,3433927263,1307055953,942726286,933058658,2468411793,3933900994,4215176142,1361170020,2001714738,2830558078,3274259782,1222529897,1679025792,2729314320,3714953764,1770335741,151462246,3013232138,1682292957,1483529935,471910574,1539241949,458788160,3436315007,1807016891,3718408830,978976581,1043663428,3165965781,1927990952,4200891579,2372276910,3208408903,3533431907,1412390302,2931980059,4132332400,1947078029,3881505623,4168226417,2941484381,1077988104,1320477388,886195818,18198404,3786409000,2509781533,112762804,3463356488,1866414978,891333506,18488651,661792760,1628790961,3885187036,3141171499,876946877,2693282273,1372485963,791857591,2686433993,3759982718,3167212022,3472953795,2716379847,445679433,3561995674,3504004811,3574258232,54117162,3331405415,2381918588,3769707343,4154350007,1140177722,4074052095,668550556,3214352940,367459370,261225585,2610173221,4209349473,3468074219,3265815641,314222801,3066103646,3808782860,282218597,3406013506,3773591054,379116347,1285071038,846784868,2669647154,3771962079,3550491691,2305946142,453669953,1268987020,3317592352,3279303384,3744833421,2610507566,3859509063,266596637,3847019092,517658769,3462560207,3443424879,370717030,4247526661,2224018117,4143653529,4112773975,2788324899,2477274417,1456262402,2901442914,1517677493,1846949527,2295493580,3734397586,2176403920,1280348187,1908823572,3871786941,846861322,1172426758,3287448474,3383383037,1655181056,3139813346,901632758,1897031941,2986607138,3066810236,3447102507,1393639104,373351379,950779232,625454576,3124240540,4148612726,2007998917,544563296,2244738638,2330496472,2058025392,1291430526,424198748,50039436,29584100,3605783033,2429876329,2791104160,1057563949,3255363231,3075367218,3463963227,1469046755,985887462} _
}
Dim Shared As ULong Pbox(0 To 17) = {608135816, 2242054355, 320440878, 57701188, 2752067618, 698298832, 137296536, 3964562569, 1160258022, 953160567, 3193202383, 887688300, 3232508343, 3380367581, 1065670069, 3041331479, 2450970073, 2306472731}
Const As ULong K232 = 4294967295 ' 2^32 - 1
Dim Shared As ULong Sbox_current(0 To 3, 0 To 255) ' Arbeitskopie der S-Boxen
Dim Shared As ULong Pbox_current(0 To 17) ' Arbeitskopie der Pbox
'************************************
'* BLOWFISH-Routinen *
' ***********************************
function Verschluessele_Blowfish(t As String, passwort As string) As String
' Blowfish-kodiert den Text t in einen Hex-String. Wenn die Länge von t kein Vielfaches von 8 sein sollte,
' wird t um CHR(3)-Bytes zu einem Vielfachen von 8 aufgefüllt.
Dim As String codetext, inter
Dim As String klartext = t
Dim As ULong tle = Len(t)
Dim As ULong final = (tle \ 8) - 1
Dim As ULong datal, datar
' Ist das Passwort seit dem letzten Aufruf geändert worden oder ist dies der erste Aufruf?
If passwort <> blowfish_lastkey Then Initialisiere_Blowfish(passwort)
codetext = ""
For block As ULong = 0 To final
tle = block * 8
inter = Mid(klartext, tle+1, 4)
datal = Vier_Ascii_in_dezimal(inter)
inter = Mid(klartext, tle+5, 4)
datar = Vier_Ascii_in_dezimal(inter)
BFenc(datal, datar) ' Blowfish-verschlüsseln
codetext = codetext & Hex(datal, 8) & Hex(datar, 8) ' Codetext als Hexstring aufbauen (könnte später komprimiert werden)
Next block
Return codetext
End Function
Function Entschluessele_Blowfish(t As String, passwort As String) As String
' Blowfish-dekodiert den Hex-Codetext t in einen Klartext-String.
Dim As ULong tle = Len(t)
Dim As ULong final = (tle \ 16) - 1
Dim As String ergebnis, inter
Dim As ulong datal, datar
If tle >= 16 then ' Datei enthält mindestens 16 Zeichen
' Ist das Passwort seit dem letzten Aufruf geändert worden oder ist dies der erste Aufruf?
If passwort <> blowfish_lastkey Then
Initialisiere_Blowfish(passwort)
endif
ergebnis = ""
For block As ULong = 0 To final
tle = block * 16
datal = ValInt("&h" & Mid(t, tle+1, 8))
datar = ValInt("&h" & Mid(t, tle+9, 8))
BFdec(datal, datar) ' Blowfish-dekodierter Text (4 ASCII-Zeichen) als Dezimalzahl
ergebnis = ergebnis & Dezimal_in_vier_ASCII(datal)
ergebnis = ergebnis & Dezimal_in_vier_ASCII(datar)
Next
Return ergebnis
Else
Return "" ' Text war nicht lang genug (Minimum 16-Hex-Zeichen)
Endif
End Function
Sub Zuruecksetzen_Blowfish()
blowfish_lastkey = "" ' Als Indikator für die Init-Routine, dass noch nicht verschlüsselt wurde (Fabrikzustand)
For i As Integer = 0 To 3 ' Die temporären Sboxes mit den Inhalten der originalen Sboxes (unvertauscht) füllen.
For j As Integer = 0 To 255
Sbox_current(i,j) = Sbox(i,j)
Next
Next
For i As Integer = 0 To 17 ' Die temporären Pboxes mit den Inhalten der originalen Pboxes (unvertauscht) füllen.
Pbox_current(i) = Pbox(i)
Next
End Sub
Function BF(xx As ULong) As ULong
' Kern-Verschlüsselungsfunktion. Bei Bruce Schneier heißt diese Funktion einfach "f".
' erhält einen vorzeichenlosen 32-Bit-Wert (xx), zerlegt ihn in seine einzelnen Bytes
' d (niedrigstwertig), c, b, a (höchstwertig) und verknüpft die Werte mit den Sboxen.
Dim As Integer a, b, c, d
Dim As ULong ergebnis
d = xx And 255 ' niedrigstwertiges Byte von xx
c = (xx And 65281) Shr 8
b = (xx And 16711681) Shr 16
a = (xx And 4278190081) Shr 24 ' höchstwertiges Byte von xx
ergebnis = (Sbox_current(0,a) + Sbox_current(1,b)) And K232
ergebnis = ergebnis Xor Sbox_current(2,c)
ergebnis = (ergebnis + Sbox_current(3,d)) And K232
Return ergebnis
End Function
sub BFenc(ByRef ql As ulong, ByRef qr As ulong)
' aus zwei vorzeichenlosen 32-Bit-Werten (l für links, r für rechts) errechnet
' diese Funktion zwei neue vorzeichenlose 32-Bit-Werte, die aus einem kodierten l und r bestehen
' (l höherwertiges 32-Bit-Quadbyte)
Dim As ULong qll = ql ' Arbeitskopien von l und r anfertigen
Dim As ULong qrr = qr
For nummer As Integer = 0 To 15
qll = qll Xor Pbox_current(nummer)
qrr = BF(qll) Xor qrr
Swap qll, qrr
Next
Swap qll, qrr
qrr = qrr Xor Pbox_current(16)
qll = qll Xor Pbox_current(17)
ql = qll
qr = qrr
End Sub
sub BFdec(ByRef ql As ulong, ByRef qr As ulong)
' aus zwei vorzeichenlosen 32-Bit-Werten (l für links, r für rechts) errechnet
' diese Funktion zwei neue vorzeichenlose 32-Bit-Werte, die aus einem dekodierten l und r bestehen
' (l höherwertiges 32-Bit-Quadbyte)
Dim As ULong qll = ql ' Arbeitskopien von l und r anfertigen
Dim As ULong qrr = qr
For nummer As Integer = 17 To 2 Step -1
qll = qll Xor Pbox_current(nummer)
qrr = BF(qll) Xor qrr
Swap qll, qrr
Next
Swap qll, qrr
qrr = qrr Xor Pbox_current(1)
qll = qll Xor Pbox_current(0)
ql = qll
qr = qrr
End Sub
Sub Initialisiere_Blowfish(key As String)
' Nur die ersten 56 Bytes des key werden benutzt. Danach wird der key zyklisch durchlaufen.
' laut Bruce Schneier erhöht das die Sicherheit des Algorithmus'.
Dim As Integer p ' Index in den key-String
Dim As ULong datum, datal, datar
Dim keylen As ULong = Len(key)
For i As Integer = 0 To 17 ' Die Pboxen reinitialisieren auf "Werkszustand", gespeichert in Pbox()
Pbox_current(i) = Pbox(i)
Next i
For box As Integer = 0 To 3 ' Die Sboxen reinitialisieren auf "Werkszustand", gespeichert in Sbox()
For nummer As Integer = 0 To 255
Sbox_current(box, nummer) = Sbox(box, nummer)
Next
Next
' Pbox_current durcheinanderbringen, mit Hilfe des Schlüssels key
p = 1
For box As Integer = 0 To 17
datum = 0
For nummer As Integer = 0 To 3
datum = (datum Shl 8) Or Asc(key, p) ' datum = datum * 256 OR ASCII-Code von key an der p.ten Stelle
p = p + 1 ' Index in den Schlüssel inkrementieren
If p > 56 Or p > keylen Then p = 0 ' Nur die ersten 56 Bytes des Schlüssels werden benutzt
Next nummer
Pbox_current(box) = Pbox(box) Or datum
Next box
' Jetzt die Pbox_current() mit dem Blowfish-Algorithmus verschlüsseln
datal = 0
datar = 0
For box As Integer = 0 To 16 Step 2
BFenc(datal, datar) ' Übergabe BYREF, datal und datar werden von BFenc "in place" verändert
Pbox_current(box) = datal
Pbox_current(box + 1) = datar
Next
' Nun noch die Sbox_current() mit Blowfish verschlüsseln
For box As Integer = 0 To 3
For nummer As Integer = 0 To 254 Step 2
BFenc(datal, datar)
Sbox_current(box, nummer) = datal
Sbox_current(box, nummer + 1) = datar
Next
Next
blowfish_lastkey = key
End Sub
' Hilfsfunktionen
Function Vier_Ascii_in_dezimal(t As string) As ULong
' Wandelt einen 4-Zeichen-ASCII-String t in eine Dezimalzahl um
Dim As ULong ergebnis
Dim As UByte b1, b2, b3, b4
b1 = Asc(t,4)
b2 = Asc(t,3)
b3 = Asc(t,2)
b4 = Asc(t,1)
ergebnis = b4 + 256 * b3 + 65536 * b2 + 16777216 * b1
Return ergebnis
End Function
Function Dezimal_in_vier_ASCII(datum As ulong) As String
' Wandelt eine Dezimalzahl in einen 4-Zeichen-ASCII-String um.
Dim As ULong xx = datum
Dim As UByte b1, b2, b3, b4
Dim As String ergebnis
b1 = xx And 255
xx = xx Shr 8
b2 = xx And 255
xx = xx Shr 8
b3 = xx And 255
b4 = xx Shr 8
ergebnis = Chr(b1) & Chr(b2) & Chr(b3) & Chr(b4)
Return ergebnis
End Function
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