ethereumjs-icap

or #ethereumjs on freenode

Utilities for handling ICAP addresses.

It works in Node.js as well as in the browser via browserify. When minified for a browser, it should be less than 4K in size.

API

• fromAddress(address, print, nonstd) - try encoding an address into an IBAN
• fromAsset(asset, print) - try encoding an asset description into an IBAN
• toAddress(iban) - try decoding an IBAN into an address
• toAsset(iban) - try decoding an IBAN into an asset description
• encode(address/asset) - encode an address or asset description into an IBAN
• decode(iban) - decode an IBAN into an address or asset description
• encodeBBAN(address/asset) - encode an address or asset description into a BBAN
• decodeBBAN(bban) - decode a BBAN into an address or asset description
• isICAP(iban) - return true if input is a valid ICAP, otherwise false
• isAddress(iban) - return true if the input is a valid ICAP with an address, otherwise false
• isAsset(iban) - return true if the input is a valid ICAP with an asset description, otherwise false

All of the above methods will throw exceptions on invalid inputs. The to* and from* method will also check for the expected inputs and outputs.

The print parameter above, when set to true, will create an IBAN in the print format, which is space delimited groups of four characters: XE73 38O0 73KY GTWW ZN0F 2WZ0 R8PX 5ZPP ZS

The address parameter only supports 0x prefixed input and will include that in the output.

The nonstd parameter of fromAddress, when set to true, will turn on support for the basic ICAP format generating an invalid IBAN, but encoding the entire 160 bits of an Ethereum address.

Examples

ICAP.fromAsset({
  asset: 'ETH',
  institution: 'XREG',
  client: 'GAVOFYORK'
})
// returns 'XE81ETHXREGGAVOFYORK'

ICAP.fromAddress('0x00c5496aee77c1ba1f0854206a26dda82a81d6d8')
// returns 'XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS'

ICAP.toAsset('XE81ETHXREGGAVOFYORK')
// returns {
//   asset: 'ETH',
//   institution: 'XREG',
//   client: 'GAVOFYORK'
// }

ICAP.toAddress('XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS')
// returns '0x00c5496aee77c1ba1f0854206a26dda82a81d6d8'

Direct address generation

A direct address ICAP is an address less than 155 bits of length and therefore it safely fits into the length restrictions of IBAN (and the checksum method used). That upper limit is 0x03ffffffffffffffffffffffffffffffffffffff or XE91GTJRJEU5043IEF993XWE21DBF0BVGF.

The following simple bruteforce code can be used to generate such addresses:

const ethUtil = require('ethereumjs-util')
function generateDirectAddress () {
  while(true) {
    var privateKey = crypto.randomBytes(32) // or your favourite other random method
    if (ethUtil.privateToAddress(privateKey)[0] <= 3) {
      return privateKey
    }
  }
}

Alternatively ethereumjs-wallet can be used to generate compatible addresses.