# Dual Data Posting Mechanisms AnyTrust introduces dual methods for posting data blocks on L1. In addition to the conventional approach of posting full data blocks, it allows for the posting of DACerts, which prove data availability. The L1 inbox contract verifies the validity of DACerts, including reference to the valid Keyset specified within the DACert. L2 code, responsible for reading data from the inbox, is designed to handle both data formats seamlessly. When encountering a DACert, it performs validity checks, including ensuring the number of signers meets the Keyset requirements, validating the aggregated signature, and verifying that the expiration time extends beyond the current L2 timestamp. Valid DACerts ensure that the data block is accessible and can be utilized by the L2 code. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://hyperdust-foundation.gitbook.io/hyperagi-docs/how-it-works/anytrust/dual-data-posting-mechanisms.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.