==== EIP 712: Ethereum typed structured data hashing and signing (DRAFT) ====
[[dido:public:ra:xapend:xapend.b_stds:defact:ethereum:eip| Return to Ethereum ERCs ]]

  : **Note**: The following is an excerpt from the official Ethereum site. It is provided here as a convenience and is not authoritative. Refer to the original document as the authoritative reference.

<table>
<caption>Data sheet for Ethereum typed structured data hashing and signing</caption>
| Title                      | Ethereum typed structured data hashing and signing |
| Author                     | Remco Bloemen, Leonid Logvinov, Jacob Evans |
| Status                     | Draft |
| Created                    | 2017-09-12  |
| Description                | [[http://eips.ethereum.org/EIPS/eip-712]] |
| Specification              | [[http://eips.ethereum.org/EIPS/eip-712#Specification]] |
| Category                   | Interface |
| Requires                   | [[dido:public:ra:xapend:xapend.b_stds:defact:ethereum:eip:erc_0155|EIP155]], [[dido:public:ra:xapend:xapend.b_stds:defact:ethereum:eip:erc_0191|EIP191]] |
</table>

=== Simple Summary === 
// Signing data is a solved problem if all we care about are bytestrings. Unfortunately in the real world we care about complex meaningful messages. Hashing structured data is non-trivial and errors result in loss of the security properties of the system.//

//As such, the adage “don’t roll your own crypto” applies. Instead, a peer-reviewed well-tested standard method needs to be used. This EIP aims to be that standard.//

=== Abstract === 
//This is a standard for hashing and signing of typed structured data as opposed to just bytestrings. It includes a//

    * //theoretical framework for correctness of encoding functions,//
    * //specification of structured data similar to and compatible with Solidity structs,//
    * //safe hashing algorithm for instances of those structures,//
    * //safe inclusion of those instances in the set of signable messages,//
    * //an extensible mechanism for domain separation,//
    * //new RPC call eth_signTypedData, and//
    * //an optimized implementation of the hashing algorithm in EVM.//

//It does not include replay protection.//