I already know to get the public key from base58 encoded private key using an ECKey object in BitcoinJ. See the example code.
String base58PrivateKeyString = "---------------------private key here---------------------"; NetworkParameters params = MainNetParams.get(); ECKey key; if (base58PrivateKeyString.length() == 51 || base58PrivateKeyString.length() == 52) { DumpedPrivateKey dumpedPrivateKey = DumpedPrivateKey.fromBase58(params, base58PrivateKeyString); key = dumpedPrivateKey.getKey(); } else { BigInteger privKey = Base58.decodeToBigInteger(base58PrivateKeyString); key = ECKey.fromPrivate(privKey); } // I'm not sure that I'm correct. Is this the correct compressed public key? String publicKey = Hex.toHexString(ECKey.publicKeyFromPrivate(Base58.decodeToBigInteger(base58PrivateKeyString), true)); String bitcoin address; // I don't know how to get
But I still don’t understand to take the compressed private key and the bitcoin address from the “key” object. I tried some with compressPoint() method. But I didn’t succeed.
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Answer
In order to get the compressed public key for a qualified WIF just use the following function in the bitcoinJ library.
String publicKey = key.getPublicKeyAsHex();