Function getMessageKeys

src/utils/nip44.ts:44–61

(
  conversationKey: Buffer,
  nonce: Buffer,
)

}

function getMessageKeys(
  conversationKey: Buffer,
  nonce: Buffer,
): { chachaKey: Buffer; chachaNonce: Buffer; hmacKey: Buffer } {
  if (conversationKey.length !== 32) {
    throw new Error('invalid conversation_key length')
  }
  if (nonce.length !== 32) {
    throw new Error('invalid nonce length')
  }

  const keys = hkdfExpand(conversationKey, nonce, 76)
  return {
    chachaKey: keys.subarray(0, 32),
    chachaNonce: keys.subarray(32, 44),
    hmacKey: keys.subarray(44, 76),
  }
}

function calcPaddedLen(unpaddedLen: number): number {
  if (unpaddedLen <= 32) {