GCM_TAG_MAX_SIZE
size_t taglen = (ctx->taglen != UNINITIALISED_SIZET) ? ctx->taglen : GCM_TAG_MAX_SIZE;
CRYPTO_gcm128_tag(&ctx->gcm, tag, GCM_TAG_MAX_SIZE);
ctx->taglen = GCM_TAG_MAX_SIZE;
ctx->taglen = GCM_TAG_MAX_SIZE;