The digest algorithm to use.
The salt value. Must be provided but can be zero-length.
Additional info value. Must be provided but can be zero-length, and cannot be more than 1024 bytes.
The length of the key to generate. Must be greater than 0. The maximum allowable value is 255
times the number of bytes produced by the selected digest function (e.g. sha512
generates 64-byte hashes, making the maximum HKDF output 16320 bytes).
HKDF is a simple key derivation function defined in RFC 5869. The given
ikm
,salt
andinfo
are used with thedigest
to derive a key ofkeylen
bytes.The supplied
callback
function is called with two arguments:err
andderivedKey
. If an errors occurs while deriving the key,err
will be set; otherwiseerr
will benull
. The successfully generatedderivedKey
will be passed to the callback as an ArrayBuffer. An error will be thrown if any of the input arguments specify invalid values or types.