Hashing Algorithms

There are many hashing algorithms used throughout the blockchain space as well as some more complex usages which require utilities to facilitate these common operations.

Cryptographic Hash Functions

The Cryptographic Hash Functions are a specific family of hash functions.

ethers.utils.id( text ) string< DataHexString< 32 > >

The Ethereum Identity function computes the KECCAK256 hash of the text bytes.

ethers.utils.keccak256( aBytesLike ) string< DataHexString< 32 > >

Returns the KECCAK256 digest aBytesLike.

ethers.utils.ripemd160( aBytesLike ) string< DataHexString< 20 > >

Returns the RIPEMD-160 digest of aBytesLike.

ethers.utils.sha256( aBytesLike ) string< DataHexString< 32 > >

Returns the SHA2-256 digest of aBytesLike.

ethers.utils.sha512( aBytesLike ) string< DataHexString< 64 > >

Returns the SHA2-512 digest of aBytesLike.

KECCAK256
utils.keccak256([ 0x12, 0x34 ]) // '0x56570de287d73cd1cb6092bb8fdee6173974955fdef345ae579ee9f475ea7432' utils.keccak256("0x") // '0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470' utils.keccak256("0x1234") // '0x56570de287d73cd1cb6092bb8fdee6173974955fdef345ae579ee9f475ea7432' // The value MUST be data, such as: // - an Array of numbers // - a data hex string (e.g. "0x1234") // - a Uint8Array // Do NOT use UTF-8 strings that are not a DataHexstring utils.keccak256("hello world") // Error: invalid arrayify value (argument="value", value="hello world", code=INVALID_ARGUMENT, version=bytes/5.0.8) // If needed, convert strings to bytes first: utils.keccak256(utils.toUtf8Bytes("hello world")) // '0x47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad' // Or equivalently use the identity function: utils.id("hello world") // '0x47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad' // Keep in mind that the string "0x1234" represents TWO // bytes (i.e. [ 0x12, 0x34 ]. If you wish to compute the // hash of the 6 characters "0x1234", convert it to UTF-8 // bytes first using utils.toUtf8Bytes. // Consider the following examples: // Hash of TWO (2) bytes: utils.keccak256("0x1234") // '0x56570de287d73cd1cb6092bb8fdee6173974955fdef345ae579ee9f475ea7432' // Hash of TWO (2) bytes: (same result) utils.keccak256([ 0x12, 0x34 ]) // '0x56570de287d73cd1cb6092bb8fdee6173974955fdef345ae579ee9f475ea7432' const bytes = utils.toUtf8Bytes("0x1234") // Uint8Array [ 48, 120, 49, 50, 51, 52 ] // Hash of SIX (6) characters (different than above) utils.keccak256(bytes) // '0x1ac7d1b81b7ba1025b36ccb86723da6ee5a87259f1c2fd5abe69d3200b512ec8' // Hash of SIX (6) characters (same result) utils.id("0x1234") // '0x1ac7d1b81b7ba1025b36ccb86723da6ee5a87259f1c2fd5abe69d3200b512ec8'
RIPEMD160
utils.ripemd160("0x") // '0x9c1185a5c5e9fc54612808977ee8f548b2258d31' utils.ripemd160("0x1234") // '0xc39867e393cb061b837240862d9ad318c176a96d'
SHA-2
utils.sha256("0x") // '0xe3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855' utils.sha256("0x1234") // '0x3a103a4e5729ad68c02a678ae39accfbc0ae208096437401b7ceab63cca0622f' utils.sha512("0x") // '0xcf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e' utils.sha512("0x1234") // '0x4c54886c9821195522d88ff4705c3e0c686b921054421e6ea598739c29c26e1ee75419aaceec94dd2e3c0dbb82ecf895c9f61215f375de6d800d9b99d3d4b816'

HMAC

ethers.utils.computeHmac( algorithm , key , data ) string< DataHexString >

Returns the HMAC of data with key using the Algorithm algorithm.

HMAC Supported Algorithms

ethers.utils.SupportedAlgorithm.sha256 string

Use the SHA2-256 hash algorithm.

ethers.utils.SupportedAlgorithm.sha512 string

Use the SHA2-512 hash algorithm.

HMAC
const key = "0x0102" const data = "0x1234" utils.computeHmac("sha256", key, data) // '0x7553df81c628815cf569696cad13a37c606c5058df13d9dff4fee2cf5e9b5779'

Hashing Helpers

ethers.utils.hashMessage( message ) string< DataHexString< 32 > >

Computes the EIP-191 personal message digest of message. Personal messages are converted to UTF-8 bytes and prefixed with \x19Ethereum Signed Message: and the length of message.

Hashing Messages
// Hashing a string message utils.hashMessage("Hello World") // '0xa1de988600a42c4b4ab089b619297c17d53cffae5d5120d82d8a92d0bb3b78f2' // Hashing binary data (also "Hello World", but as bytes) utils.hashMessage( [ 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100 ]) // '0xa1de988600a42c4b4ab089b619297c17d53cffae5d5120d82d8a92d0bb3b78f2' // NOTE: It is important to understand how strings and binary // data is handled differently. A string is ALWAYS processed // as the bytes of the string, so a hexstring MUST be // converted to an ArrayLike object first. // Hashing a hex string is the same as hashing a STRING // Note: this is the hash of the 4 characters [ '0', 'x', '4', '2' ] utils.hashMessage("0x42") // '0xf0d544d6e4a96e1c08adc3efabe2fcb9ec5e28db1ad6c33ace880ba354ab0fce' // Hashing the binary data // Note: this is the hash of the 1 byte [ 0x42 ] utils.hashMessage([ 0x42 ]) // '0xd18c12b87124f9ceb7e1d3a5d06a5ac92ecab15931417e8d1558d9a263f99d63' // Hashing the binary data // Note: similarly, this is the hash of the 1 byte [ 0x42 ] utils.hashMessage(utils.arrayify("0x42")) // '0xd18c12b87124f9ceb7e1d3a5d06a5ac92ecab15931417e8d1558d9a263f99d63'
ethers.utils.namehash( name ) string< DataHexString< 32 > >

Returns the ENS Namehash of name.

Namehash
utils.namehash("") // '0x0000000000000000000000000000000000000000000000000000000000000000' utils.namehash("eth") // '0x93cdeb708b7545dc668eb9280176169d1c33cfd8ed6f04690a0bcc88a93fc4ae' utils.namehash("ricmoo.firefly.eth") // '0x0bcad17ecf260d6506c6b97768bdc2acfb6694445d27ffd3f9c1cfbee4a9bd6d' utils.namehash("ricmoo.xyz") // '0x7d56aa46358ba2f8b77d8e05bcabdd2358370dcf34e87810f8cea77ecb3fc57d'

Typed Data Encoder

The TypedDataEncoder is used to compute the various encoded data required for EIP-712 signed data.

Signed data requires a domain, list of structures and their members and the data itself.

The domain is an object with values for any of the standard domain properties.

The types is an object with each property being the name of a structure, mapping to an array of field descriptions. It should not include the EIP712Domain property unless it is required as a child structure of another.

Experimental Feature (this exported class name will change)

This is still an experimental feature. If using it, please specify the exact version of ethers you are using (e.g. spcify "5.0.18", not "^5.0.18") as the exported class name will be renamed from _TypedDataEncoder to TypedDataEncoder once it has been used in the field a bit.

ethers.utils._TypedDataEncoder.from( types ) [TypedDataEncoder]

Creates a new TypedDataEncoder for types. This object is a fairly low-level object that most developers should not require using instances directly.

Most developers will find the static class methods below the most useful.

TypedDataEncoder.encode( domain , types , values ) string

Encodes the Returns the hashed EIP-712 domain.

TypedDataEncoder.getPayload( domain , types , value ) any

Returns the standard payload used by various JSON-RPC eth_signTypedData* calls.

All domain values and entries in value are normalized and the types are verified.

TypedDataEncoder.getPrimaryType( types ) string

Constructs a directed acyclic graph of the types and returns the root type, which can be used as the primaryType for EIP-712 payloads.

TypedDataEncoder.hash( domain , types , values ) string< DataHexString< 32 > >

Returns the computed EIP-712 hash.

TypedDataEncoder.hashDomain( domain ) string< DataHexString< 32 > >

Returns the hashed EIP-712 domain.

TypedDataEncoder.resolveNames( domain , types , value , resolveName ) Promise< any >

Returns a copy of value, where any leaf value with a type of address will have been recursively replacedwith the value of calling resolveName with that value.

Typed Data Example
const domain = { name: 'Ether Mail', version: '1', chainId: 1, verifyingContract: '0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC' } // The named list of all type definitions const types = { Person: [ { name: 'name', type: 'string' }, { name: 'wallet', type: 'address' } ], Mail: [ { name: 'from', type: 'Person' }, { name: 'to', type: 'Person' }, { name: 'contents', type: 'string' } ] } // The data to sign const value = { from: { name: 'Cow', wallet: '0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826' }, to: { name: 'Bob', wallet: '0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB' }, contents: 'Hello, Bob!' } TypedDataEncoder.encode(domain, types, value) // '0x1901f2cee375fa42b42143804025fc449deafd50cc031ca257e0b194a650a912090fc52c0ee5d84264471806290a3f2c4cecfc5490626bf912d01f240d7a274b371e' TypedDataEncoder.getPayload(domain, types, value) // { // domain: { // chainId: '1', // name: 'Ether Mail', // verifyingContract: '0xcccccccccccccccccccccccccccccccccccccccc', // version: '1' // }, // message: { // contents: 'Hello, Bob!', // from: { // name: 'Cow', // wallet: '0xcd2a3d9f938e13cd947ec05abc7fe734df8dd826' // }, // to: { // name: 'Bob', // wallet: '0xbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb' // } // }, // primaryType: 'Mail', // types: { // Mail: [ // { // name: 'from', // type: 'Person' // }, // { // name: 'to', // type: 'Person' // }, // { // name: 'contents', // type: 'string' // } // ], // Person: [ // { // name: 'name', // type: 'string' // }, // { // name: 'wallet', // type: 'address' // } // ] // } // } TypedDataEncoder.getPrimaryType(types) // 'Mail' TypedDataEncoder.hash(domain, types, value) // '0xbe609aee343fb3c4b28e1df9e632fca64fcfaede20f02e86244efddf30957bd2' TypedDataEncoder.hashDomain(domain) // '0xf2cee375fa42b42143804025fc449deafd50cc031ca257e0b194a650a912090f'

Solidity Hashing Algorithms

When using the Solidity abi.packEncoded(...) function, a non-standard tightly packed version of encoding is used. These functions implement the tightly packing algorithm.

ethers.utils.solidityPack( types , values ) string< DataHexString >

Returns the non-standard encoded values packed according to their respective type in types.

ethers.utils.solidityKeccak256( types , values ) string< DataHexString< 32 > >

Returns the KECCAK256 of the non-standard encoded values packed according to their respective type in types.

ethers.utils.soliditySha256( types , values ) string< DataHexString< 32 > >

Returns the SHA2-256 of the non-standard encoded values packed according to their respective type in types.

Solidity Hashing
utils.solidityPack([ "int16", "uint48" ], [ -1, 12 ]) // '0xffff00000000000c' utils.solidityPack([ "string", "uint8" ], [ "Hello", 3 ]) // '0x48656c6c6f03' utils.solidityKeccak256([ "int16", "uint48" ], [ -1, 12 ]) // '0x81da7abb5c9c7515f57dab2fc946f01217ab52f3bd8958bc36bd55894451a93c' utils.soliditySha256([ "int16", "uint48" ], [ -1, 12 ]) // '0xa5580fb602f6e2ba9c588011dc4e6c2335e0f5d970dc45869db8f217efc6911a' // As a short example of the non-distinguished nature of // Solidity tight-packing (which is why it is inappropriate // for many things from a security point of view), consider // the following examples are all equal, despite representing // very different values and layouts. utils.solidityPack([ "string", "string" ], [ "hello", "world01" ]) // '0x68656c6c6f776f726c643031' utils.solidityPack([ "string", "string" ], [ "helloworld", "01" ]) // '0x68656c6c6f776f726c643031' utils.solidityPack([ "string", "string", "uint16" ], [ "hell", "oworld", 0x3031 ]) // '0x68656c6c6f776f726c643031' utils.solidityPack([ "uint96" ], [ "32309054545061485574011236401" ]) // '0x68656c6c6f776f726c643031'