Hashing Algorithms

Explain what hash functions are?

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 computs 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/5.0.4) // 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.

ethers.utils.namehash( name ) string< DataHexString< 32 > >

Returns the ENS Namehash of name.

Hashing Messages
// @TODO: include examples of hashMessage; it can be complex. :)
Namehash
utils.namehash("") // '0x0000000000000000000000000000000000000000000000000000000000000000' utils.namehash("eth") // '0x93cdeb708b7545dc668eb9280176169d1c33cfd8ed6f04690a0bcc88a93fc4ae' utils.namehash("ricmoo.firefly.eth") // '0x0bcad17ecf260d6506c6b97768bdc2acfb6694445d27ffd3f9c1cfbee4a9bd6d' utils.namehash("ricmoo.xyz") // '0x7d56aa46358ba2f8b77d8e05bcabdd2358370dcf34e87810f8cea77ecb3fc57d'

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 respecive 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'