delphi THashSHA2在大文件上返回一个错误的SHA256
Data.Cloud.CloudAPI.pas具有class function TCloudSHA256Authentication.GetStreamToHashSHA256Hex(const Content: TStream): string; 在某些文件上返回错误的SHA 256。
class function TCloudSHA256Authentication.GetStreamToHashSHA256Hex(const Content: TStream): string;
var
LBytes : TBytes;
Hash: THashSHA2;
begin
LBytes := TBytesStream(Content).Bytes;
//Hash bytes
Hash := THashSHA2.Create;
Hash.Update(LBytes);
Result := Hash.HashAsString;
end;
AWS S3返回错误：
提供的x-amz-content-sha256头与计算的不匹配
GetStreamToHashSHA256Hex似乎从亚马逊产生了一个不同的sha256：
<ClientComputedContentSHA256>f43ee89e2b7758057bb1f33eb8546d4c2c118f2ab932de89dbd74aabc0651053</ClientComputedContentSHA256>
<S3ComputedContentSHA256>3bbf5f864cc139cf6392b4623bd782a69d16929db713bffaa68035f8a5c3c0ce</S3ComputedContentSHA256>
我用myfile.zip（600 MB）做了一些测试......
TIdHashSHA256替代Indy返回右边的SHA256（与aws s3相同），例如：
var
aFileStream: TFileStream;
aHash: TIdHashSHA256;
begin
aFileStream := TFileStream.Create('C:myfile.zip', fmOpenRead or fmShareDenyWrite);
aHash := TIdHashSHA256.Create;
try
Result := aHash.HashStreamAsHex(aFileStream).ToLower;
finally
aFileStream.Free;
aHash.Free;
end;
end;
来自PHP的hash_file()返回正确的SHA256（与aws s3相同），例如：
hash_file('sha256', 'C:myfile.zip');
但THashSHA2返回一个错误的sha256，例如：
var
LBytes : TBytes;
Hash: THashSHA2;
begin
LBytes := TFile.ReadAllBytes('C:myfile.zip');
Hash := THashSHA2.Create;
Hash.Update(LBytes);
Result := Hash.HashAsString;
end;
为什么？
UPDATE
这是我的错误修复。 将Data.Cloud.CloudAPI.pas导入项目并重写这些函数：
uses IdHash, IdHashSHA, IdSSLOpenSSL;
class function TCloudSHA256Authentication.GetHashSHA256Hex( HashString: string): string;
var
aHash: TIdHashSHA256;
begin
LoadOpenSSLLibrary;
try
if not(TIdHashSHA256.IsAvailable) then
raise Exception.Create('HashSHA256 Isn''t available!');
aHash := TIdHashSHA256.Create;
try
Result := aHash.HashStringAsHex(HashString).ToLower;
finally
aHash.Free;
end;
finally
UnLoadOpenSSLLibrary;
end;
end;
class function TCloudSHA256Authentication.GetStreamToHashSHA256Hex(const Content: TStream): string;
var
aHash: TIdHashSHA256;
begin
LoadOpenSSLLibrary;
try
if not(TIdHashSHA256.IsAvailable) then
raise Exception.Create('HashSHA256 Isn''t available!');
aHash := TIdHashSHA256.Create;
try
Result := aHash.HashStreamAsHex(Content).ToLower;
finally
aHash.Free;
end;
finally
UnLoadOpenSSLLibrary;
end;
end;
更新2
我也尝试实施FredS的建议，它的工作原理：
class function TCloudSHA256Authentication.GetHashSHA256Hex( HashString: string): string;
var
Content: TStringStream;
Hash: THashSHA2;
LBytes: TArray<Byte>;
Buffer: PByte;
BufLen: Integer;
Readed: Integer;
begin
BufLen := 16 * 1024;
Buffer := AllocMem(BufLen);
Hash := THashSHA2.Create;
Content := TStringStream.Create(HashString);
try
while Content.Position < Content.Size do
begin
Readed := Content.Read(Buffer^, BufLen);
if Readed > 0 then
Hash.update(Buffer^, Readed);
end;
finally
Content.Free;
FreeMem(Buffer);
end;
Result := Hash.HashAsString;
end;
class function TCloudSHA256Authentication.GetStreamToHashSHA256Hex(const Content: TStream): string;
var
LBytes : TBytes;
Hash: THashSHA2;
Buffer: PByte;
BufLen: Integer;
Readed: Integer;
begin
BufLen := 16 * 1024;
Buffer := AllocMem(BufLen);
Hash := THashSHA2.Create;
try
Content.Seek(0, soFromBeginning);
while Content.Position < Content.Size do
begin
Readed := Content.Read(Buffer^, BufLen);
if Readed > 0 then
Hash.update(Buffer^, Readed);
end;
Content.Seek(0, soFromBeginning);
finally
FreeMem(Buffer);
end;
Result := Hash.HashAsString;
end;
我刚刚在柏林使用MS Cyrpto和THashSHA2测试了一个+1.5 GB的文件，他们都返回了相同的散列，但像OpenSSL这样的MS Crypto速度更快。
问题在于该文件太大而无法在一个块中保存TBytes。 我的记录帮手有TBytes.MaxLen = $F000; {61440} TBytes.MaxLen = $F000; {61440}因此，您需要使用TFileStream并将文件分块读入HashSHA2.Update。
更新：按照David Heffernan的评论，我重新测试了TBytes.MaxLen，它似乎只受可用内存的限制。
MS Crypto和Delphi HashSha2的实例和速度比较
注意：需要Jedi API
program SHA2SpeedTest;
{$APPTYPE CONSOLE}
{$R *.res}
uses
JwaWindows, Winapi.Windows, System.SysUtils, System.Classes, System.Diagnostics, System.Hash;
const
SHA256_LEN = 256 div 8;
ChunkSize = $F000;
type
TBytesHelper = record helper for TBytes
public
function BinToHex: string;
end;
function TBytesHelper.BinToHex: string;
var
Len : Integer;
begin
Len := Length(Self);
SetLength(Result, Len * 2));
System.Classes.BinToHex(Self, PChar(Result), Len);
end;
procedure DelphiHash256(const AStream: TStream; out Bytes: TBytes);
var
HashSHA2: THashSHA2;
BytesRead: Integer;
begin
HashSHA2 := THashSHA2.create;
SetLength(Bytes, ChunkSize);
AStream.Position := 0;
repeat
BytesRead := AStream.Read(Bytes, ChunkSize);
if (BytesRead = 0) then Break; // Done
HashSHA2.Update(Bytes, BytesRead);
until False;
Bytes := HashSHA2.HashAsBytes;
end;
function CryptoHash256(const AStream: TStream; out Bytes: TBytes): Boolean;
var
SigLen : Cardinal;
hHash : HCRYPTHASH;
hProv : HCRYPTPROV;
BytesRead: Integer;
begin
hProv := 0; hHash := 0;
Result := False;
If not CryptAcquireContext(hProv, nil, nil, PROV_RSA_AES, CRYPT_VERIFYCONTEXT) then Exit;
try
if not CryptCreateHash(hProv, CALG_SHA_256, 0, 0, hHash) then Exit;
try
SetLength(Bytes, ChunkSize);
AStream.Position := 0;
repeat
BytesRead := AStream.Read(Bytes, ChunkSize);
if (BytesRead = 0) then Break; // Done
if not CryptHashData(hHash, @Bytes[0], BytesRead, 0) then Exit;
until False;
SigLen := SHA256_LEN;
SetLength(Bytes, SigLen);
Result := CryptGetHashParam(hHash, HP_HASHVAL, @Bytes[0], SigLen, 0);
finally
CryptDestroyHash(hHash);
end;
finally
CryptReleaseContext(hProv, 0);
end;
end;
var
Stream: TStream;
Bytes : TBytes;
sw : TStopwatch;
CryptoTicks : int64;
FileName : string;
{* CheckFileName *}
function CheckFileName: boolean;
begin
if (FileName='') then FileName := ParamStr(0);
Result := FileExists(FileName);
if not Result then Writeln('Invalid File name');
end;
begin
repeat
Writeln('Please Enter a valid File name, empty for this Executable');
Readln(FileName);
until CheckFileName;
try
Stream := TFileStream.Create(FileName, fmOpenRead + fmShareDenyNone);
try
WriteLn('Crypto - Calculating Checksum');
sw.Start;
if not CryptoHash256(Stream, Bytes) then raise Exception.Create('Something Happened :)');
sw.Stop;
Writeln(Bytes.BinToHex);
WriteLn('Elapsed: ' + sw.Elapsed.ToString);
CryptoTicks := sw.ElapsedTicks;
WriteLn('Delphi - Calculating Checksum');
sw.Reset; sw.Start;
DelphiHash256(Stream, Bytes);
sw.Stop;
Writeln(Bytes.BinToHex);
WriteLn('Elapsed: ' + sw.Elapsed.ToString);
Writeln(Format('MS Crypto is %d%% faster', [(sw.ElapsedTicks-CryptoTicks) * 100 div CryptoTicks]));
finally
Stream.Free;
end;
Writeln('Hit <Enter> to exit');
Readln;
except
on E: Exception do Writeln(E.ClassName, ': ', E.Message);
end;
end.