using System;
namespace myMethod
{
class computeMD5andSHA1
{
/// <summary>
/// 计算文件的 MD5 值
/// </summary>
/// <param name="fileName">要计算 MD5 值的文件名和路径</param>
/// <returns>MD5 值16进制字符串</returns>
public string MD5File ( string fileName )
{
return HashFile ( fileName , "md5" );
}
/// <summary>
/// 计算文件的 sha1 值
/// </summary>
/// <param name="fileName">要计算 sha1 值的文件名和路径</param>
/// <returns>sha1 值16进制字符串</returns>
public string SHA1File ( string fileName )
{
return HashFile ( fileName , "sha1" );
}
/// <summary>
/// 计算文件的哈希值
/// </summary>
/// <param name="fileName">要计算哈希值的文件名和路径</param>
/// <param name="algName">算法:sha1,md5</param>
/// <returns>哈希值16进制字符串</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>
/// 计算哈希值
/// </summary>
/// <param name="stream">要计算哈希值的 Stream</param>
/// <param name="algName">算法:sha1,md5</param>
/// <returns>哈希值字节数组</returns>
private byte[] HashData ( System.IO.Stream stream , string algName )
{
System.Security.Cryptography.HashAlgorithm algorithm;
if ( algName == null )
{
throw new ArgumentNullException
( "algName 不能为 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 只能使用 sha1 或 md5" ); }
algorithm = System.Security.Cryptography.MD5.Create();
}
return algorithm.ComputeHash ( stream );
}
/// <summary>
/// 字节数组转换为16进制表示的字符串
/// </summary>
private string ByteArrayToHexString ( byte[] buf )
{
return BitConverter.ToString ( buf ).Replace ( "-" , "" );
}
}
}