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| 2 | daniel-mar | 1 | {Copyright: Hagen Reddmann HaReddmann at T-Online dot de |
| 2 | Author: Hagen Reddmann |
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| 3 | Remarks: freeware, but this Copyright must be included |
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| 4 | known Problems: none |
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| 5 | Version: 5.1, Delphi Encryption Compendium |
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| 6 | Delphi 2-4, BCB 3-4, designed and testet under D3-5 |
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| 7 | Description: secure protected Random Number Generator based on Yarrow |
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| 8 | |||
| 9 | * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS |
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| 10 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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| 11 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 12 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE |
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| 13 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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| 14 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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| 15 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
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| 16 | * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
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| 17 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE |
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| 18 | * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, |
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| 19 | * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 20 | } |
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| 21 | |||
| 22 | unit DECRandom; |
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| 23 | |||
| 24 | interface |
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| 25 | |||
| 26 | implementation |
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| 27 | |||
| 28 | uses SysUtils, DECUtil, DECFmt, DECHash; |
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| 29 | |||
| 30 | var |
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| 31 | RandomClass: TDECHashClass = THash_SHA1; |
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| 32 | FRegister: array[0..127] of Byte; |
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| 33 | FCounter: Cardinal; |
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| 34 | FHash: TDECHash = nil; |
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| 35 | |||
| 36 | function DoProcess: Byte; |
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| 37 | begin |
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| 38 | if not IsObject(FHash, RandomClass) then FHash := RandomClass.Create; |
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| 39 | FHash.Init; |
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| 40 | FHash.Calc(FCounter, SizeOf(FCounter)); |
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| 41 | FHash.Calc(FRegister, SizeOf(FRegister)); |
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| 42 | FHash.Done; |
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| 43 | FRegister[FCounter mod SizeOf(FRegister)] := FRegister[FCounter mod SizeOf(FRegister)] xor FHash.Digest[0]; |
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| 44 | Inc(FCounter); |
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| 45 | Result := FHash.Digest[1]; // no real predictable dependency to above FHash.Digest[0] ! |
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| 46 | end; |
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| 47 | |||
| 48 | procedure DoBuffer(var Buffer; Size: Integer); |
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| 49 | var |
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| 50 | I: Integer; |
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| 51 | begin |
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| 52 | for I := 0 to Size -1 do |
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| 53 | TByteArray(Buffer)[I] := DoProcess; |
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| 54 | end; |
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| 55 | |||
| 56 | procedure DoSeed(const Buffer; Size: Integer); |
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| 57 | var |
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| 58 | I: Integer; |
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| 59 | T: Cardinal; |
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| 60 | begin |
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| 61 | if Size >= 0 then |
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| 62 | begin |
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| 63 | // initalize a repeatable Seed |
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| 64 | FillChar(FRegister, SizeOf(FRegister), 0); |
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| 65 | FCounter := 0; |
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| 66 | for I := 0 to Size -1 do |
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| 67 | FRegister[I mod SizeOf(FRegister)] := FRegister[I mod SizeOf(FRegister)] xor TByteArray(Buffer)[I]; |
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| 68 | end else |
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| 69 | begin |
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| 70 | // initalize a non-repeatable Seed based on Timers, |
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| 71 | // ATTENTION! this way isn't secure inpredictable, |
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| 72 | // the user should call RandomSeed(Data, SizeOf(Data)) instead, |
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| 73 | // where Date contains as example collected informations based on Human inputs. |
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| 74 | T := RandomSystemTime; |
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| 75 | for I := Low(FRegister) to High(FRegister) do |
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| 76 | begin |
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| 77 | FRegister[I] := FRegister[I] xor Byte(T); |
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| 78 | T := T shl 1 or T shr 31; |
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| 79 | end; |
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| 80 | end; |
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| 81 | for I := Low(FRegister) to High(FRegister) do |
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| 82 | DoProcess; |
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| 83 | FCounter := 0; |
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| 84 | end; |
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| 85 | |||
| 86 | procedure DoInit; |
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| 87 | begin |
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| 88 | DoRandomBuffer := DoBuffer; |
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| 89 | DoRandomSeed := DoSeed; |
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| 90 | DoSeed('', 0); |
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| 91 | end; |
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| 92 | |||
| 93 | procedure DoDone; |
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| 94 | begin |
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| 95 | try |
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| 96 | FHash.Free; |
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| 97 | except |
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| 98 | end; |
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| 99 | FHash := nil; |
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| 100 | FillChar(FRegister, SizeOf(FRegister), 0); |
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| 101 | FCounter := 0; |
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| 102 | end; |
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| 103 | |||
| 104 | initialization |
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| 105 | DoInit; |
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| 106 | finalization |
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| 107 | DoDone; |
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| 108 | end. |