hpkeLabeledExpand

Compute the output of the LabeledExpand function as defined in RFC9180.

Syntax

Public Function hpkeLabeledExpand ( _
    nBytes As Long, _
    lpPrk() As Byte, _
    szLabel As String, _
    lpInfo() As Byte, _
    szCurveName As String, _
    Optional nOptions As Long = 0 _
) As Byte()

Parameters

nBytes

Required number of bytes (L) of output keying material.

lpPrk

Pseudorandom key.

szLabel

Label string.

lpInfo

Byte string info.

szCurveName

Name of ECDH curve used in scheme. Specify one of:

 "P-256" | "P-384" | "P-521" | "X25519" | "X448"

nOptions

Use to specify the AEAD encryption algorithm used in the scheme (if applicable). Specify either: Zero (0) to indicate that the KDF is being used inside a KEM algorithm or, if used in the remainder of HPKE, one of:

PKI_AEAD_AES_128_GCM
PKI_AEAD_AES_256_GCM
PKI_AEAD_CHACHA20_POLY1305

Return Value

Remarks