HMAC()

Creates a hash-based message authentication code (HMAC) for the given message combined with a given secret key using an optional algorithm and encoding.

HMACs are used to verify the data integrity and authenticity of a transmitted message.

The hash function used by the HMAC function depends on the algorithm specified.

HMAC( message=object, key=object, algorithm=string, encoding=string );

Returns: String

Argument Description Default
message
object, required

The message to be hashed. Can be a string or a byte array.
key
object, required

The secret cryptographic key to be combined with the message and hashed. Can be a string or a byte array.
algorithm
string, optional

The algorithm to use for hashing your input. The following values are supported:

  • HmacMD5
  • HmacSHA1
  • HmacSHA256
  • HMACSHA384
  • HMACSHA512

HmacMD5
encoding
string, optional

The character encoding to use when converting the message to bytes. Must be a character encoding name recognized by the Java runtime.

  • utf-8
  • iso-8859-1
  • windows-1252
  • us-ascii
  • shift_jis
  • iso-2022-jp
  • euc-jp
  • euc-kr
  • big5
  • euc-cn
  • utf-16

Alias: charset

Examples

message = 'this is a test';
    key = 'ABC123';

<span class="c">// Using the required fields only</span>
<span class="nv">result</span> <span class="o">=</span> <span class="nf">HMAC</span><span class="p">(</span> <span class="nv">message</span><span class="p">,</span> <span class="nv">key</span> <span class="p">);</span>
<span class="nf">writeDump</span><span class="p">(</span> <span class="nv">result</span> <span class="p">);</span> <span class="c">// 776770430C93778AD6F91B43A4A30B69</span>
<span class="c">// Using the optional algorithm parameter (HmacSHA1)</span>
<span class="nv">algorithm</span> <span class="o">=</span> <span class="s1">&#39;HmacSHA1&#39;</span><span class="p">;</span>
<span class="nv">result</span> <span class="o">=</span> <span class="nf">HMAC</span><span class="p">(</span> <span class="nv">message</span><span class="p">,</span> <span class="nv">key</span><span class="p">,</span> <span class="nv">algorithm</span> <span class="p">);</span>
<span class="nf">writeDump</span><span class="p">(</span> <span class="nv">result</span> <span class="p">);</span> <span class="c">// 049E53BAE339C4A05587D7BBBA2857548E8FC327</span>
<span class="c">// Using the optional algorithm parameter (HmacSHA256)</span>
<span class="nv">algorithm</span> <span class="o">=</span> <span class="s1">&#39;HmacSHA256&#39;</span><span class="p">;</span>
<span class="nv">result</span> <span class="o">=</span> <span class="nf">HMAC</span><span class="p">(</span> <span class="nv">message</span><span class="p">,</span> <span class="nv">key</span><span class="p">,</span> <span class="nv">algorithm</span> <span class="p">);</span>
<span class="nf">writeDump</span><span class="p">(</span> <span class="nv">result</span> <span class="p">);</span> <span class="c">// 0503949602EDE3FF61C84F4CE51C99EEA2961CAA144AEE552F7D120AD6A60D7D</span>
<span class="c">// Using the optional encoding parameter (UTF-8)</span>
<span class="nv">encoding</span> <span class="o">=</span> <span class="s1">&#39;UTF-8&#39;</span><span class="p">;</span>
<span class="nv">result</span> <span class="o">=</span> <span class="nf">HMAC</span><span class="p">(</span> <span class="nv">message</span><span class="p">,</span> <span class="nv">key</span><span class="p">,</span> <span class="nv">algorithm</span><span class="p">,</span> <span class="nv">encoding</span> <span class="p">);</span>
<span class="nf">writeDump</span><span class="p">(</span> <span class="nv">result</span> <span class="p">);</span> <span class="c">// 0503949602EDE3FF61C84F4CE51C99EEA2961CAA144AEE552F7D120AD6A60D7D</span>

See also