/// <Summary>
/// Calculate the MD5 value of a file
/// </Summary>
/// <Param name = "FILENAME"> Name and path of the file to calculate the MD5 Value </Param>
/// <Returns> MD5 value: A hexadecimal string </Returns>
Public String Md5file ( String Filename)
{
Return Hashfile (filename, " MD5 " );
}
/// <Summary>
/// Calculate the sha1 value of the file
/// </Summary>
/// <Param name = "FILENAME"> Name and path of the file to calculate the sha1 Value </Param>
/// <Returns> Sha1 value hexadecimal string </Returns>
Public String Sha1file ( String Filename)
{
Return Hashfile (filename, " Sha1 " );
}
/// <Summary>
/// Calculate the file hash value
/// </Summary>
/// <Param name = "FILENAME"> Name and path of the file to calculate the hash value </Param>
/// <Param name = "algname"> Algorithm: Sha1, MD5 </Param>
/// <Returns> Hash Value: A hexadecimal string </Returns>
Private String Hashfile ( String Filename, String Algname)
{
If ( ! System. Io. file. exists (filename ))
Return String . Empty;
System. Io. filestream FS = New System. Io. filestream (filename, system. Io. filemode. Open, system. Io. fileaccess. Read );
Byte [] Hashbytes = Hashdata (FS, algname );
FS. Close ();
Return Bytearraytohexstring (hashbytes );
}
/// <Summary>
/// Calculate the hash value
/// </Summary>
/// <Param name = "stream"> Stream to calculate the hash value </Param>
/// <Param name = "algname"> Algorithm: sha1, MD5 </Param>
/// <Returns> Hash Value byte array </Returns>
Private Byte [] Hashdata (system. Io. Stream stream, String Algname)
{
System. Security. cryptography. hashalgorithm algorithm;
If (Algname = Null )
{
Throw New Argumentnullexception ( " Algname cannot be null " );
}
If ( String . Compare (algname, " Sha1 " , True ) = 0 )
{
Algorithm = System. Security. cryptography. sha1.create ();
}
Else
{
If ( String . Compare (algname, " MD5 " , True ) ! = 0 )
{
Throw New Exception ( " Algname can only use sha1 or MD5 " );
}
Algorithm = System. Security. cryptography. md5.create ();
}
Return Algorithm. computehash (Stream );
}
/// <Summary>
/// Byte array to a hexadecimal string
/// </Summary>
Private String Bytearraytohexstring ( Byte [] BUF)
{
Return Bitconverter. tostring (BUF). Replace ( " - " , "" );
} |
