signing.swift

/**
{ 
  "exchangeContractAddress" : "0x12459c951127e0c374ff9105dda097662a027093", 
  "maker" : "0x8c7d76d9aef6a104b500cfd1746c331f4da5bce8", 
  "taker" : "0x0000000000000000000000000000000000000000", 
  "makerTokenAddress" : "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
  "takerTokenAddress" : "0xe41d2489571d322189246dafa5ebde1f4699f498",
  "feeRecipient" : "0xa258b39954cef5cb142fd567a46cddb31a670124",
  "makerTokenAmount" : "1950100000000000",
  "takerTokenAmount" : "1000000000000000000",
  "makerFee" : "0", 
  "takerFee" : "0",  
  "expirationUnixTimestampSec" : "1526921772",
  "salt" : "86785906954588868942673379887384221477103830402997510744810924003638980963919", 
  "ecSignature" : { 
    "r" : "0x806197f32b842430dc15508e1d04c7794543273f1b6cf9fd997417448268e4ba", 
    "v" : 28, 
    "s" : "0x44ae08ffa24152f60c86b071be80d2ac18aed968b5d29baf1cf3f7b07b99ee98" 
  } 
}
*/
let message: BytesScalar = ConcatenatedBytes(
    bytes: [
        BytesFromHexString(
            hex: "0x12459c951127e0c374ff9105dda097662a027093"
        ),
        BytesFromHexString(
            hex: "0x8c7d76d9aef6a104b500cfd1746c331f4da5bce8"
        ),
        BytesFromHexString(
            hex: "0x0000000000000000000000000000000000000000"
        ),
        BytesFromHexString(
            hex: "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
        ),
        BytesFromHexString(
            hex: "0xe41d2489571d322189246dafa5ebde1f4699f498"
        ),
        BytesFromHexString(
            hex: "0xa258b39954cef5cb142fd567a46cddb31a670124"
        ),
        LeftZeroesPaddedBytes(
            origin: BytesFromHexString(
                hex: "06ED9B09C6C800"
            ),
            padding: 32
        ),
        LeftZeroesPaddedBytes(
            origin: BytesFromHexString(
                hex: "0DE0B6B3A7640000"
            ),
            padding: 32
        ),
        LeftZeroesPaddedBytes(
            origin: BytesFromHexString(
                hex: "00"
            ),
            padding: 32
        ),
        LeftZeroesPaddedBytes(
            origin: BytesFromHexString(
                hex: "00"
            ),
            padding: 32
        ),
        LeftZeroesPaddedBytes(
            origin: BytesFromHexString(
                hex: "5B02FA2C"
            ),
            padding: 32
        ),
        BytesFromHexString(
            hex: "BFDF1526B0814C13561DD504979F4BBB1E9BA84DBAF50DBB24B046B76A08EE4F"
        )
    ]
)

let pk = try SECP256k1Signature(
    privateKey: EthPrivateKey(
        bytes: BytesFromHexString(
            hex: fatalError("YOUR PRIVATE KEY HERE")
        )
    ),
    message: ConcatenatedBytes(
        bytes: [
            UTF8StringBytes(
                string: SimpleString(
                    string: "\u{19}Ethereum Signed Message:\n32" //32 because keccak256 is always 32
                )
            ),
            Keccak256Bytes(
                origin: message
            )
        ]
    ),
    hashFunction: SHA3(variant: .keccak256).calculate
)
print(
    try! "r: " + pk.r().value().toHexString() 
)
print(
    try! "s: " + pk.s().value().toHexString()
)
print(
    try! "recid: " + "\(pk.recoverID().value())"
)