Dummy implementation of DES (used by RPCRuntime)
DESDummy.mesa
Last Edited by: Andrew Birrell, September 7, 1983 4:45 pm
DIRECTORY
BasicTime USING[ GetClockPulses ],
DESFace,
Basics USING[ BITXOR ];
DESDummy: MONITOR
IMPORTS Basics, BasicTime
EXPORTS DESFace
SHARES DESFace
= BEGIN
OPEN DESFace;
Words4: TYPE = MACHINE DEPENDENT RECORD[w1, w2, w3, w4: WORD];
XOR64: PROCEDURE[a, b, out: LONG POINTER] = INLINE
BEGIN
OPEN
aLP: LOOPHOLE[a, LONG POINTER TO Words4],
bLP: LOOPHOLE[b, LONG POINTER TO Words4],
outP: LOOPHOLE[out, LONG POINTER TO Words4];
outP.w1 ← Basics.BITXOR[aLP.w1, bLP.w1];
outP.w2 ← Basics.BITXOR[aLP.w2, bLP.w2];
outP.w3 ← Basics.BITXOR[aLP.w3, bLP.w3];
outP.w4 ← Basics.BITXOR[aLP.w4, bLP.w4];
END;
Words2: TYPE = MACHINE DEPENDENT RECORD[w1, w2: WORD];
XOR32: PROCEDURE[a, b: LONG UNSPECIFIED, out: POINTER] = INLINE
BEGIN
OPEN
aP: LOOPHOLE[a, Words2],
bP: LOOPHOLE[b, Words2],
outP: LOOPHOLE[out, POINTER TO Words2];
outP.w1 ← Basics.BITXOR[aP.w1, bP.w1];
outP.w2 ← Basics.BITXOR[aP.w2, bP.w2];
END;
cachedKey: Key;
noKeyCached: BOOLEAN ← TRUE;
BadParity: ERROR = CODE;
InternalizeKey: ENTRY PROC [keyP: POINTER TO Key] =
BEGIN
IF noKeyCached OR cachedKey # keyP^ THEN
BEGIN
FOR i: CARDINAL IN [0..7] DO
IF keyP[i].p # parityTable[keyP[i].b]
THEN RETURN WITH ERROR BadParity;
ENDLOOP;
cachedKey ← keyP^;
noKeyCached ← FALSE;
END;
END; --InternalizeKey--
NotImplemented: ERROR = CODE;
CryptData: PUBLIC PROCEDURE [keyP: POINTER TO Key, nBlks: CARDINAL,
from, to: Blocks, direction: Direction, mode: Mode,
seedP: LONG POINTER TO IV ← NIL] =
BEGIN
newSeed: IV;
IF mode = checksum THEN ERROR NotImplemented;
IF mode = cbcCheck AND direction = encrypt AND nBlks > 0
THEN BEGIN
FOR blk: CARDINAL IN [0..nBlks-1)
DO XOR64[@from[nBlks-1], @from[blk], @from[nBlks-1]] ENDLOOP;
END;
InternalizeKey[keyP];
FOR blk: CARDINAL IN [0 .. nBlks) DO
IF mode#ecb THEN
IF direction=encrypt
THEN XOR64[@from[blk], seedP, @from[blk]]
ELSE newSeed ← from[blk];
XOR64[keyP, @from[blk], @to[blk]];
IF mode#ecb THEN
IF direction=encrypt
THEN seedP ← @to[blk]
ELSE {XOR64[@to[blk], seedP, @to[blk]]; seedP^ ← newSeed};
ENDLOOP;
IF mode = cbcCheck AND direction = decrypt AND nBlks > 0
THEN BEGIN
FOR blk: CARDINAL IN [0..nBlks-1)
DO XOR64[@to[nBlks-1], @to[blk], @to[nBlks-1]] ENDLOOP;
END
END; --CryptData--
randomSeed: Block ← [1,2,3,4];
GetRandomIV: PUBLIC PROCEDURE RETURNS [iv: IV] =
BEGIN
-- Ideally, this should use a true random number generator --
prevSeed: Block ← randomSeed;
pulse1: POINTER TO LONG CARDINAL = LOOPHOLE[@randomSeed[0]];
pulse2: POINTER TO LONG CARDINAL = LOOPHOLE[@randomSeed[2]];
seedKey: POINTER TO Key = LOOPHOLE[@randomSeed];
pulse1^ ← pulse1^ + BasicTime.GetClockPulses[];
XOR32[pulse2^, BasicTime.GetClockPulses[], pulse2];
CorrectParity[seedKey];
CryptData[keyP: seedKey, nBlks: 1,
from: LOOPHOLE[LONG[@prevSeed], Blocks],
to: LOOPHOLE[LONG[@iv], Blocks],
direction: encrypt, mode: ecb, seedP: NIL];
END; --GetRandomIV--
GetRandomKey: PUBLIC PROCEDURE RETURNS [k: Key] =
BEGIN
k ← LOOPHOLE[GetRandomIV[]];
CorrectParity[@k];
END; --GetRandomKey--
MakeKey: PUBLIC PROCEDURE [source: LONG STRING]
RETURNS [key: Key] =
BEGIN
User interface routine to construct a 64 bit key from an ASCII string.
"key" is an array that holds the 64 bit key.
Note: every eighth bit of "key" is an odd parity bit for the preceeding seven bits.
key ← nullKey;
FOR i: CARDINAL IN [0..source.length) DO
j: CARDINAL = i MOD 8;
c: CHARACTER = IF source[i] IN ['A..'Z] THEN 'a + (source[i]-'A) ELSE source[i];
key[j].b ← Basics.BITXOR[LOOPHOLE[c, [0 .. 127]], key[j].b];
ENDLOOP;
CorrectParity[@key];
END; -- MakeKey
parityTable: PACKED ARRAY [0..127] OF [0..1] ← [
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0
];
CorrectParity: PUBLIC PROC[keyP: LONG POINTER TO Key] =
BEGIN
FOR i: CARDINAL IN [0 .. 7] DO
keyP[i].p ← parityTable[keyP[i].b];
ENDLOOP;
END;
[] ← GetRandomKey[];
END. --DES--