HTML <keygen> Tag
This tag has now been removed from the HTML5 specification. Rather than remove this article altogether, I have decided to keep it here for reference.
The HTML <keygen> tag generates a cryptographic key pair in an HTML document.
The <keygen> tag can be used for generating signed certificates, which can be used to authenticate to services that use Transport Layer Security (TLS) and certificate authentication. When the <keygen> element's form is submitted, the private key is stored in the local keystore, and the public key is packaged and sent to the server.
The <keygen> element provides the user with a range of key size options. It may also provide a choice of where to generate the key, for example in a smart card or in software and stored on disk. In this case the user's browser would need to be configured to support cryptographic hardware.
Syntax
The <keygen> tag could typically be written as <keygen name="" challenge="" keytype=""> (no end tag), with relevant values applied to the name, challenge, and keytype attributes.
Like this:
Example
Here's an example of using the <keygen> tag to generate a cryptographic key pair.
Attributes
Attributes can be added to an HTML element to provide more information about how the element should appear or behave.
There are 3 kinds of attributes that you can add to your HTML tags: Element-specific, global, and event handler content attributes.
The <keygen> element accepts the following attributes.
Element-Specific Attributes
This table shows the attributes that are specific to the <keygen> tag/element.
| Attribute | Description |
|---|---|
| autofocus | Automatically gives focus to this control when the page loads. This allows the user to start using the control without having to select it first. There must not be more than one element in the document with the autofocus attribute specified.
This is a boolean attribute. If the attribute is present, its value must either be the empty string or a value that is an ASCII case-insensitive match for the attribute's canonical name, with no leading or trailing whitespace (i.e. either Possible values:
|
| challenge | Specifies whether or not the value of the keygen is be challenged when submitted. |
| disabled | Disables the control. The control won't accept changes from the user. It also cannot receive focus and will be skipped when tabbing.
This is a boolean attribute. If the attribute is present, its value must either be the empty string or a value that is an ASCII case-insensitive match for the attribute's canonical name, with no leading or trailing whitespace (i.e. either Possible values:
|
| form | Specifies the ID of a form to which this control belongs.
Possible values: [The ID of a form element in the element's owner |
| keytype | Specifies a key type. For example, the value "RSA" specifies an RSA key. |
| name | Assigns a name to the input control. |
Global Attributes
The following attributes are standard across all HTML5 elements. Therefore, you can use these attributes with the <keygen> tag , as well as with all other HTML tags.
- accesskey
- class
- contenteditable
- contextmenu
- dir
- draggable
- dropzone
- hidden
- id
- inert
- itemid
- itemprop
- itemref
- itemscope
- itemtype
- lang
- spellcheck
- style
- tabindex
- title
- translate
For a full explanation of these attributes, see HTML 5 global attributes.
Event Handler Content Attributes
Event handler content attributes enable you to invoke a script from within your HTML. The script is invoked when a certain "event" occurs. Each event handler content attribute deals with a different event.
Below are the standard HTML5 event handler content attributes.
Again, you can use any of these with the <keygen> element, as well as any other HTML5 element.
- onabort
- oncancel
- onblur
- oncanplay
- oncanplaythrough
- onchange
- onclick
- oncontextmenu
- ondblclick
- ondrag
- ondragend
- ondragenter
- ondragexit
- ondragleave
- ondragover
- ondragstart
- ondrop
- ondurationchange
- onemptied
- onended
- onerror
- onfocus
- onformchange
- onforminput
- oninput
- oninvalid
- onkeydown
- onkeypress
- onkeyup
- onload
- onloadeddata
- onloadedmetadata
- onloadstart
- onmousedown
- onmousemove
- onmouseout
- onmouseover
- onmouseup
- onmousewheel
- onpause
- onplay
- onplaying
- onprogress
- onratechange
- onreadystatechange
- onscroll
- onseeked
- onseeking
- onselect
- onshow
- onstalled
- onsubmit
- onsuspend
- ontimeupdate
- onvolumechange
- onwaiting
For a full explanation of these attributes, see HTML 5 event handler content attributes.
Differences Between HTML 4 & HTML 5
The <keygen> tag is new in HTML5.
To see more detail on the two versions see HTML5 <keygen> Tag. Also check out the links to the official specifications below.
Template
Here's a template for the <keygen> tag with all available attributes for the tag (based on HTML5). These are grouped into attribute types, each type separated by a space. In many cases, you will probably only need one or two (if any) attributes. Simply remove the attributes you don't need.
For more information on attributes for this tag, see HTML5 <keygen> Tag.
Tag Details
For more details about the <keygen> tag, see HTML5 <keygen> Tag.
Specifications
Here are the official specifications for the <keygen> element.
- HTML5 Specification (W3C)
- HTML Living Standard (WHATWG)
- Current W3C Draft (the next version that is currently being worked on)
What's the Difference?
W3C creates "snapshot" specifications that don't change once defined. So the HTML5 specification won't change once it becomes an official recommendation. WHATWG on the other hand, develops a "living standard" that is updated on a regular basis. In general, you will probably find that the HTML living standard will be more closely aligned to the current W3C draft than to the HTML5 specification.