SHA256WITHDSA verify problem about cryptolib4pascal HOT 2 CLOSED

program Demo;

{$APPTYPE CONSOLE}
{$R *.res}

uses

  ClpISigner,
  ClpBigInteger,
  ClpDsaParameters,
  ClpDsaPublicKeyParameters,
  HlpConverters,
  SysUtils,
   // additional imports
  ClpSignersEncodings,
  ClpIDsaPublicKeyParameters,
  ClpDsaDigestSigner,
  ClpDsaSigner,
  ClpIDsaSigner,
  ClpISignersEncodings,
  ClpDigestUtilities,
  ClpIDigest,
  ClpAsn1Objects,
  ClpIAsn1Objects,
  ClpCryptoLibTypes;

const
  SIGNATURE_FAIL =
    '3044022091481D2DD4902030BE5E941DC41D51051D38C8D6B52BD638F166AA0B285FD4540220729B054A4C1977D7F423FCCCE8531AB77DA4F4871415B948FA9FFC43B1653282';

  CONTENT_FAIL =
    '789C0B8D77F3718D30343630B4304FDAC4D0F690F7A05A4789A8204723AB4C8BF366ADB3338A5E2DE06A60E09B76E8C9B317A7EE70ACBB74E326238BCB753B4606A552898BEA218B3DCC7C2C5628275E3C1D27176BB4F8C2E7'
    + 'DF17263B444573CF9EAD9D1825EDBDF8C422E3C9DCC5D1C6AB272F74CAE6F62EF404099EACDAECCD7991F16167E3C1C64F56AB8A16063A0969090639694D9A1964A41864A59554582555A59518945495941864E5E921C720C3'
    + 'D0BA809391415572E3D487074F4E5D7AC6C0C0C2202CD4C010489B33A43030303032A9ADF431972861BF2051665BC4C0605B2C011465000972DC61E39528AB926B00722CB0A9B080AA10CA040088455F38';

  SIGNATURE_OK =
    '30440220782E2FE184A1D85E89E9338B298EC61AEBA248CE722056CA940A967C8A1D391202206E2C628C4FCEA91BA35216A0A350F894DE5EBD7B8909920FDE947FEEDE0E20C4';

  CONTENT_OK =
    '789C01BC0043FF555F464C455831333031383862B20086E10DC125EA2815110881051C844464D985668E23A00A80000E96C2E4E6E8CADC08AED2D8D9010444D7BE0100221CE610EA559B64364C38A82361D1CB5E1E5D32A3D0'
    + '979BD099C8426B0B7373432B4B6852932BABA3634B733B2B715AB34B09D101E18981C181F1424221521291521292A17A3A920A11525A095282314952B20A49529952826278083001A4C38AE5BB303ACE700380070014B00240'
    + '400F537570657220537061727072656973C41E4A03';

  PARAM_Y = '2071026581109650758038184064186458876296283481300943403866509942342382524620713451396343254114684899675018096590369661320483283915891166582478643454906082539533084932998847762533'
    + '5608491474738708319155141091176484174426011647105714888522392044284457605524311380058563471942453792467869956630831044794802346458000950850660797317292702519780588741916026340669'
    + '3620012965050922147558298228550935029104266071742567822000080296983419837677125515674745912823376511707389352243244256981176594257823975113333238642501605713186198500548884663216'
    + '55183209104790133727137773539483537009121119915647022479430130140834128010355366147';

  PARAM_P = '3017316225751025747816503856735074390137150438484287902337126460736744030289225070797062368697742354219140574539404572855291510404700630125513899004636916104465988521873694530966'
    + '1318177566530870929805256382987168067340008563174311414346376485783727860627287576374105590638940189925715546485395628902605554021519590402931608393003737437115405244576740720698'
    + '4835770992100788644604476304620720569870221703221752857037022257117195563165249290086072514593243867291836699225079470118050740478512600855228566314481165933907549303663373092953'
    + '25310946756575679469440910701253806730076290075220214443090215694678030619287443651';

  PARAM_Q = '89726923024951955097649575600463773741813068174113684889543146019116433923879';

  PARAM_G = '6682738806820039844008521695401888626604434767682364664746866004152999420930735095644239980782167926920540357506540943531558003772634839218334759316089889548468135218808036392037'
    + '2011689222919790333697690344631663740976611841320173892965305518127096861572682348179792158029674307464324521180906853686018459823737125128895604673978691732918869443789114925806'
    + '5472811992020860821346955758135422858848014563792522516932207263405005445975349224466539540552903706733887641939394032980403211285416125003974316524504106159538430710214970562737'
    + '4089518329951756701893447901613868789330561624574500181839826906305067813553340963';

type
  TCustomStandardDsaEncoding = class sealed(TStandardDsaEncoding)
  strict protected
    function CheckValue(const n, x: TBigInteger): TBigInteger; override;
    function EncodeValue(const n, x: TBigInteger): IDerInteger; override;
  end;

  { TCustomStandardDsaEncoding }

function TCustomStandardDsaEncoding.CheckValue(const n, x: TBigInteger)
  : TBigInteger;
begin
if (not n.IsInitialized) then
begin
   raise EArgumentCryptoLibException.Create('value not initialized');
end;

  if ((x.CompareTo(n) >= 0)) then
  begin
    raise EArgumentCryptoLibException.CreateResFmt(@SValueOutOfRange, ['x']);
  end;

  if (x.SignValue < 0) then
  begin
    result := TBigInteger.Create(1, x.ToByteArray()); // force r or s to be positive
    Exit;
  end;
  result := x;
end;

function TCustomStandardDsaEncoding.EncodeValue(const n, x: TBigInteger)
  : IDerInteger;
begin
// ensure we get the positive bytes before creating our DerInteger
  result := TDerInteger.Create(CheckValue(n, x).ToByteArrayUnsigned()); 
end;

function TestCase(const Content, Signature: string): Boolean;
var
  Signer: ISigner;
  PubKey: IDSAPublicKeyParameters;
  msgBytes, sigBytes: TBytes;
  DigestInstance: IDigest;
begin
  sigBytes := TConverters.ConvertHexStringToBytes(Signature);
  msgBytes := TConverters.ConvertHexStringToBytes(Content);

  PubKey := TDsaPublicKeyParameters.Create(TBigInteger.Create(PARAM_Y),
    TDsaParameters.Create(TBigInteger.Create(PARAM_P),
    TBigInteger.Create(PARAM_Q), TBigInteger.Create(PARAM_G)));

  DigestInstance := TDigestUtilities.GetDigest('SHA256');
  Signer := TDsaDigestSigner.Create(TDsaSigner.Create() as IDsaSigner,
    DigestInstance, TCustomStandardDsaEncoding.Create() as IDsaEncoding);

  Signer.Init(False, PubKey);
  Signer.BlockUpdate(msgBytes, 0, Length(msgBytes));

  result := Signer.VerifySignature(sigBytes);
end;

begin
  try
    { TODO -oUser -cConsole Main : Insert code here }
    if not TestCase(CONTENT_OK, SIGNATURE_OK) then
      Writeln('Case 1 failed');
    if not TestCase(CONTENT_FAIL, SIGNATURE_FAIL) then
      Writeln('Case 2 failed');
    Readln;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;

end.