if(fullKey == null) throw new SSKVerifyException("Need full key to reconstruct an SSK");
NodeSSK key;
key = NodeSSK.construct(fullKey);
if(knownPublicKey != null)
key.setPubKey(knownPublicKey);
else if(!key.grabPubkey(pubkeyCache, canReadClientCache, canReadSlashdotCache, meta))
throw new SSKVerifyException("No pubkey found");
SSKBlock block = new SSKBlock(data, headers, key, false);
return block;
}