Generate an Address

Follow along with the steps below to build a transaction from scratch using built-in bcoin utilities. These steps are based on those outlined in the Bitcoin Wiki.

Of course, if you're using the bcoin wallet module, it will do these steps for you automatically when you generate an address!

// https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses

secp256k1 = require("bcoin/lib/crypto/secp256k1")
crypto = require("bcoin/lib/crypto")
base58 = require("bcoin/lib/utils/base58")

// 0 - Having a private ECDSA key
privkey = buffer.Buffer.from("18E14A7B6A307F426A94F8114701E7C8E774E7F9A47E2C2035DB29A206321725", "hex")

// 1 - Take the corresponding public key generated with it (65 bytes, 1 byte 0x04, 32 bytes corresponding to X coordinate, 32 bytes corresponding to Y coordinate)
pubkey = secp256k1.publicKeyCreate(privkey, false)

// 2 - Perform SHA-256 hashing on the public key
step2 = crypto.sha256(pubkey)

// 3 - Perform RIPEMD-160 hashing on the result of SHA-256
step3 = crypto.ripemd160(step2)

// 4 - Add version byte in front of RIPEMD-160 hash (0x00 for Main Network)
step4 = buffer.Buffer.concat([buffer.Buffer.alloc(1), step3])

// 5 - Perform SHA-256 hash on the extended RIPEMD-160 result
step5 = crypto.sha256(step4)

// 6 - Perform SHA-256 hash on the result of the previous SHA-256 hash
step6 = crypto.sha256(step5)

// 7 - Take the first 4 bytes of the second SHA-256 hash. This is the address checksum
step7 = step6.slice(0, 4)

// 8 - Add the 4 checksum bytes from stage 7 at the end of extended RIPEMD-160 hash from stage 4. This is the 25-byte binary Bitcoin Address.
step8 = buffer.Buffer.concat([step4, step7])

// 9 - Convert the result from a byte string into a base58 string using Base58Check encoding. This is the most commonly used Bitcoin Address format
addr = base58.encode(step8)