final String keyWrapAlgo = userMeta.get(Headers.CRYPTO_KEYWRAP_ALGORITHM);
final boolean isKMS = isKMSKeyWrapped(keyWrapAlgo);
final Map<String, String> core = matdescFromJson(matdescStr);
final Map<String, String> merged = isKMS || extra == null
? core : extra.mergeInto(core);
final EncryptionMaterials materials;
if (isKMS) {
materials = new KMSEncryptionMaterials(
core.get(KMSEncryptionMaterials.CUSTOMER_MASTER_KEY_ID));
materials.addDescriptions(core);
} else {
materials = kekMaterialAccessor == null
? null
: kekMaterialAccessor.getEncryptionMaterials(merged)
;