工作需要根据资料写的一个SHA1RSA算法

工作需要根据资料写的一个SHA1RSA算法其中用到了libeay32.dll和ssleay32.dll，版本不限制，直接从官方下载源码然后编译
function ReadPrivateKey(AFileName: TFileName): pEVP_PKEY; //读取私钥文件
var
keyfile: pBIO;
function cb(buffer: PChar; blength: integer;
  verify: integer; data: pointer): integer; cdecl;
var
  Passphrase: String;
begin
    result := 0;
end;
begin
  keyfile   :=   BIO_new(BIO_s_file());
  BIO_read_filename(keyfile,   PChar(AFilename));
  result   :=   PEM_read_bio_PrivateKey(keyfile, nil, @cb, nil);
  BIO_free(keyfile);
end;

function ReadPublicKey(AFileName: TFileName): pEVP_PKEY;//读取公钥文件
var
keyfile: pBIO;
function cb(buffer: PChar; blength: integer;
  verify: integer; data: pointer): integer; cdecl;
var
  Passphrase: String;
begin
   result := 0;
end;
begin
  keyfile := BIO_new(BIO_s_file());
  BIO_read_filename(keyfile, PChar(AFilename));
  result := PEM_read_bio_PUBKEY(keyfile, nil, @cb, nil);
  BIO_free(keyfile);
end;

function SHA1RSA_Sign(str, keystr: string):string;//签名
var
fp: TextFile;
key: pEVP_PKEY;
mdLength: dword;
mdValue: array [0..2200] of byte;
mdctx: EVP_MD_CTX;
inbuf: array [0..1023] of char;
dirname, ss, keyfile: string;
i: integer;
begin
result:= '';
ss:= '';
dirname:= ExtractFilePath(paramstr(0))+'key\';

Randomize;
    keyfile:=dirname+ 'prv_'+ inttostr(Random(1000000))+ '.pem';
try
    If not DirectoryExists(dirname) then
      CreateDir(dirname);
    try
    AssignFile(fp, keyfile);
    if not FileExists(keyfile) then
        Rewrite(fp);
    Append(fp);
    Writeln(fp, keystr);
    Flush(fp);
    CloseFile(fp);
  except
    Flush(fp);
    CloseFile(fp);
    raise;
  end;
  except
  end;
  try
   key := ReadPrivateKey(keyfile);
  finally
   deletefile(keyfile);
end;
if key <> nil then
begin
  try
  StrPCopy(inbuf, str);
  EVP_SignInit(@mdctx, EVP_sha1());
    EVP_SignUpdate(@mdctx, @inbuf, StrLen(inbuf));
    mdLength:= 0;
    EVP_SignFinal(@mdctx, @mdValue, mdLength, key);
    for i:= 0 to mdLength- 1 do
     ss:=   ss+inttohex(mdValue,2);
    result     :=ss;
  finally
    EVP_PKEY_free(key);
  end;
  end;
end;

function SHA1RSA_Verify(plainstr, pubkeystr, sigstr:string):boolean;//对比认证
var    
fp: TextFile;
key: pEVP_PKEY;
mdLength: dword;
mdValue: array [0..2200] of byte;
mdctx: EVP_MD_CTX;
inbuf: array [0..1023] of char;
dirname, ss, keyfile: string;
i,ret: integer;
begin
result:= false;
ss:= '';
dirname:= ExtractFilePath(paramstr(0))+'key\';
Randomize;
    keyfile:=dirname+ 'pub_'+ inttostr(Random(1000000))+ '.pem';
try
    If not DirectoryExists(dirname) then
      CreateDir(dirname);
    try
    AssignFile(fp, keyfile);
    if not FileExists(keyfile) then
        Rewrite(fp);
    Append(fp);
    Writeln(fp, pubkeystr);
    Flush(fp);
    CloseFile(fp);
  except
    Flush(fp);
    CloseFile(fp);
    raise;
  end;
  except
  end;
  try
   key := ReadPublicKey(keyfile);
  finally
   deletefile(keyfile);
end;
if key <> nil then
  begin
  try
  StrPCopy(inbuf, plainstr);
  EVP_VerifyInit(@mdctx, EVP_sha1());
  EVP_VerifyUpdate(@mdctx, @inbuf, StrLen(inbuf));
  mdLength := 128;
  for i:= 0 to 127 do
    begin
      mdValue:= strtoint('$'+sigstr[2*i+1]+sigstr[2*i+2]);
      ss:= ss+  inttostr(strtoint('$'+sigstr[2*i+1]+sigstr[2*i+2]));
    end;
    ret:= EVP_VerifyFinal(@mdctx,@mdValue, mdLength, key);
    if ret= 1 then
     result:= true;
  finally
    EVP_PKEY_free(key);
  end;
  end;
end;