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MD5

MD5 is a hashing algorithm that generates a 128-bit hash value. It may be formatted in a number of different ways, where a 32-byte hexadecimal string is the most popular.

In Skybrud.Essentials the SecurityUtils class in the Skybrud.Essentials.Security namespace contains both the GetMd5Hash and GetMd5HashFromFile methods as well as the GetMd5Guid method.

GetMd5Hash

The GetMd5Hash method takes an input string and returns a 32-byte hexadecimal string:

// Generate the MD5 hash
string hash = SecurityUtils.GetMd5Hash("Hello there!");

// Outputs "a77b55332699835c035957df17630d28"
Console.WriteLine(hash);

The method has few different method that let you control the output - eg. whether the generated hash should be in lower case (default) or upper case:

// Generate the MD5 hash
string hash = SecurityUtils.GetMd5Hash("Hello there!", HexFormat.LowerCase);

// Outputs "a77b55332699835c035957df17630d28"
Console.WriteLine(hash);

// Generate the MD5 hash
string hash = SecurityUtils.GetMd5Hash("Hello there!", HexFormat.UpperCase);

// Outputs "A77B55332699835C035957DF17630D28"
Console.WriteLine(hash);

By default Encoding.UTF8 is used when generating the hash, but it's also possibly to explicitly specify the encoding:

// Generate the MD5 hash
string hash = SecurityUtils.GetMd5Hash("Rød grød med fløde", Encoding.ASCII));

// Outputs "769aeeb3658f0cb83c0ae16f1303e08b"
Console.WriteLine(hash);

// Generate the MD5 hash
string hash = SecurityUtils.GetMd5Hash("Rød grød med fløde", Encoding.UTF8));

// Outputs "64d6f69ac402593bc004c8adf3db4b22"
Console.WriteLine(hash);

and also both HEX format and an encoding:

// Generate the MD5 hash
string hash = SecurityUtils.GetMd5Hash("Rød grød med fløde", HexFormat.LowerCase, Encoding.ASCII));

// Outputs "769aeeb3658f0cb83c0ae16f1303e08b"
Console.WriteLine(hash);

// Generate the MD5 hash
string hash = SecurityUtils.GetMd5Hash("Rød grød med fløde", HexFormat.LowerCase, Encoding.UTF8));

// Outputs "64d6f69ac402593bc004c8adf3db4b22"
Console.WriteLine(hash);

GetMd5HashFromFile

The GetMd5HashFromFile method lets you generate a MD5 hash directly from a file on disk:

// Generate the MD5 hash
Guid hash = SecurityUtils.GetMd5hashFromFile("c:/obi-wan.txt");

// Outputs "a77b55332699835c035957df17630d28"
Console.WriteLine(hash);

The method will read the raw bytes of the file, meaning it isn't necessary to specify an encoding to be used.

GetMd5Guid

A MD5 hash has a length that also makes it suitable to be represented as a GUID:

// Generate the MD5 hash
Guid hash = SecurityUtils.GetMd5Guid("Hello there!");

// Outputs "33557ba7-9926-5c83-0359-57df17630d28"
Console.WriteLine(hash);

// Generate the MD5 hash
Guid hash = SecurityUtils.GetMd5Guid("Hello there!", Encoding.UTF8);

// Outputs "33557ba7-9926-5c83-0359-57df17630d28"
Console.WriteLine(hash);
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