Package com.yahoo.security.hpke

Interface Kdf

public interface Kdf
Key derivation function (KDF)
Author:
vekterli

  • Method Summary

    Modifier and Type
    Method
    Description
    byte[]
    expand(byte[] prk, byte[] info, int nBytesToExpand)
    Expand a pseudorandom key prk using optional string info into nBytesToExpand bytes of output keying material.
    byte[]
    extract(byte[] salt, byte[] labeledIkm)
    Extract a pseudorandom key of fixed length nH() bytes from input keying material ikm and an optional byte string salt.
    static Kdf
    hkdfSha256()
     
    short
    kdfId()
    Predefined KDF ID, as given in RFC 9180 section 7.2
    short
    nH()
    Output size of the extract() function in bytes

  • Method Details

    • extract

      byte[] extract(byte[] salt, byte[] labeledIkm)
      Extract a pseudorandom key of fixed length nH() bytes from input keying material ikm and an optional byte string salt.
      Parameters:
      salt - non-secret salt used as input to KDF
      labeledIkm - secret input keying material
      Returns:
      nH bytes of PRK data

    • expand

      byte[] expand(byte[] prk, byte[] info, int nBytesToExpand)
      Expand a pseudorandom key prk using optional string info into nBytesToExpand bytes of output keying material.
      Parameters:
      prk - pseudo random key previously gotten from a call to extract.
      info - contextual info for expansion; useful for key domain separation
      nBytesToExpand - number of bytes to return
      Returns:
      nBytesToExpand bytes of output keying material.

    • nH

      short nH()
      Output size of the extract() function in bytes

    • kdfId

      short kdfId()
      Predefined KDF ID, as given in RFC 9180 section 7.2

    • hkdfSha256

      static Kdf hkdfSha256()