Need a way to convert a public key to an address

truedat101 commented 6 years ago

Review NEM's approach: https://docs.nem.io/en/address-components/address-components-2 Review section 2.3 https://www.nem.io/wp-content/themes/nem/files/NEM_techRef.pdf

Steps:

Perform 256-bit Sha3 on the public key
Perform 160-bit Ripemd of hash resulting from step 1.
Prepend version byte to Ripemd hash (either 0x68 or 0x98)
Perform 256-bit Sha3 on the result, take the first four bytes as a checksum
Concatenate output of step 3 and the checksum from step 4
Encode result using base32

This is the JS code directly out of their example in the documentation:

private static String generateEncoded(final byte version, final byte[] publicKey) {
                // step 1: sha3 hash of the public key
                final byte[] sha3PublicKeyHash = Hashes.sha3_256(publicKey);

                // step 2: ripemd160 hash of (1)
                final byte[] ripemd160StepOneHash = Hashes.ripemd160(sha3PublicKeyHash);

                // step 3: add version byte in front of (2)
                final byte[] versionPrefixedRipemd160Hash = ArrayUtils.concat(new byte[] { version }, ripemd160StepOneHash);

                // step 4: get the checksum of (3)
                final byte[] stepThreeChecksum = generateChecksum(versionPrefixedRipemd160Hash);

                // step 5: concatenate (3) and (4)
                final byte[] concatStepThreeAndStepSix = ArrayUtils.concat(versionPrefixedRipemd160Hash, stepThreeChecksum);

                // step 6: base32 encode (5)
                return Base32Encoder.getString(concatStepThreeAndStepSix);
        }

truedat101 commented 6 years ago

NOTE, it looks like the NEM project is using Bouncy Castle and also a java wrapper around NACL.

pedroalvesbatista commented 6 years ago

Are all that features covered in libsodium, I mean, the SHA-3 algorithm and the checksum proccesses ?

truedat101 commented 6 years ago

Look at the api. My understanding is we have everything we need in libsodium, however, we need to perform steps 1-6 using those apis.

truedat101 commented 6 years ago

Moving this into next milestone.

pedroalvesbatista commented 6 years ago

I'm starting to generate some skeleton here and scratch the algorithm, based on the updates you @truedat101 made with genericHash.