306 lines
9.9 KiB
PHP
306 lines
9.9 KiB
PHP
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<?php
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/*
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Copyright (c) 2018 Monero-Integrations
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*/
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require_once("SHA3.php");
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require_once("ed25519.php");
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require_once("base58.php");
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class Cryptonote
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{
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protected $ed25519;
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public function __construct()
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{
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$this->ed25519 = new ed25519();
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$this->base58 = new base58();
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}
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/*
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* @param string Hex encoded string of the data to hash
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* @return string Hex encoded string of the hashed data
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*
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*/
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public function keccak_256($message)
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{
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$keccak256 = SHA3::init (SHA3::KECCAK_256);
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$keccak256->absorb (hex2bin($message));
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return bin2hex ($keccak256->squeeze (32)) ;
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}
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/*
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* @return string A hex encoded string of 32 random bytes
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*
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*/
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public function gen_new_hex_seed()
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{
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$bytes = random_bytes(32);
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return bin2hex($bytes);
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}
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public function sc_reduce($input)
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{
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$integer = $this->ed25519->decodeint(hex2bin($input));
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$modulo = bcmod($integer , $this->ed25519->l);
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$result = bin2hex($this->ed25519->encodeint($modulo));
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return $result;
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}
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/*
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* Hs in the cryptonote white paper
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*
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* @param string Hex encoded data to hash
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*
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* @return string A 32 byte encoded integer
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*/
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public function hash_to_scalar($data)
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{
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$hash = $this->keccak_256($data);
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$scalar = $this->sc_reduce($hash);
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return $scalar;
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}
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/*
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* Derive a deterministic private view key from a private spend key
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* @param string A private spend key represented as a 32 byte hex string
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*
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* @return string A deterministic private view key represented as a 32 byte hex string
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*/
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public function derive_viewKey($spendKey)
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{
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return $this->hash_to_scalar($spendkey);
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}
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/*
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* Generate a pair of random private keys
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*
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* @param string A hex string to be used as a seed (this should be random)
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*
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* @return array An array containing a private spend key and a deterministic view key
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*/
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public function gen_private_keys($seed)
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{
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$spendKey = $this->sc_reduce($seed);
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$viewKey = $this->derive_viewKey($spendKey);
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$result = array("spendKey" => $spendKey,
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"viewKey" => $viewKey);
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return $result;
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}
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/*
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* Get a public key from a private key on the ed25519 curve
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*
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* @param string a 32 byte hex encoded private key
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*
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* @return string a 32 byte hex encoding of a point on the curve to be used as a public key
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*/
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public function pk_from_sk($privKey)
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{
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$keyInt = $this->ed25519->decodeint(hex2bin($privKey));
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$aG = $this->ed25519->scalarmult_base($keyInt);
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return bin2hex($this->ed25519->encodepoint($aG));
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}
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/*
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* Generate key derivation
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*
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* @param string a 32 byte hex encoding of a point on the ed25519 curve used as a public key
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* @param string a 32 byte hex encoded private key
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*
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* @return string The hex encoded key derivation
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*/
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public function gen_key_derivation($public, $private)
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{
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$point = $this->ed25519->scalarmult($this->ed25519->decodepoint(hex2bin($public)), $this->ed25519->decodeint(hex2bin($private)));
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$res = $this->ed25519->scalarmult($point, 8);
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return bin2hex($this->ed25519->encodepoint($res));
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}
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public function encode_varint($data)
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{
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$orig = $data;
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if ($data < 0x80)
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{
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return bin2hex(pack('C', $data));
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}
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$encodedBytes = [];
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while ($data > 0)
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{
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$encodedBytes[] = 0x80 | ($data & 0x7f);
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$data >>= 7;
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}
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$encodedBytes[count($encodedBytes)-1] &= 0x7f;
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$bytes = call_user_func_array('pack', array_merge(array('C*'), $encodedBytes));;
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return bin2hex($bytes);
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}
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public function derivation_to_scalar($der, $index)
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{
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$encoded = $this->encode_varint($index);
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$data = $der . $encoded;
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return $this->hash_to_scalar($data);
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}
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// this is a one way function used for both encrypting and decrypting 8 byte payment IDs
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public function stealth_payment_id($payment_id, $tx_pub_key, $viewkey)
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{
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if(strlen($payment_id) != 16)
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{
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throw new Exception("Error: Incorrect payment ID size. Should be 8 bytes");
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}
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$der = $this->gen_key_derivation($tx_pub_key, $viewkey);
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$data = $der . '8d';
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$hash = $this->keccak_256($data);
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$key = substr($hash, 0, 16);
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$result = bin2hex(pack('H*',$payment_id) ^ pack('H*',$key));
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return $result;
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}
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// takes transaction extra field as hex string and returns transaction public key 'R' as hex string
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public function txpub_from_extra($extra)
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{
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$parsed = array_map("hexdec", str_split($extra, 2));
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if($parsed[0] == 1)
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{
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return substr($extra, 2, 64);
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}
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if($parsed[0] == 2)
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{
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if($parsed[0] == 2 || $parsed[2] == 1)
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{
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$offset = (($parsed[1] + 2) *2) + 2;
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return substr($extra, (($parsed[1] + 2) *2) + 2, 64);
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}
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}
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}
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public function derive_public_key($der, $index, $pub)
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{
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$scalar = $this->derivation_to_scalar($der, $index);
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$sG = $this->ed25519->scalarmult_base($this->ed25519->decodeint(hex2bin($scalar)));
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$pubPoint = $this->ed25519->decodepoint(hex2bin($pub));
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$key = $this->ed25519->encodepoint($this->ed25519->edwards($pubPoint, $sG));
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return bin2hex($key);
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}
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/*
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* Perform the calculation P = P' as described in the cryptonote whitepaper
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*
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* @param string 32 byte transaction public key R
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* @param string 32 byte reciever private view key a
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* @param string 32 byte reciever public spend key B
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* @param int output index
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* @param string output you want to check against P
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*/
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public function is_output_mine($txPublic, $privViewkey, $publicSpendkey, $index, $P)
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{
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$derivation = $this->gen_key_derivation($txPublic, $privViewkey);
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$Pprime = $this->derive_public_key($derivation, $index, $publicSpendkey);
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if($P == $Pprime)
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{
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return true;
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}
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else
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return false;
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}
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/*
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* Create a valid base58 encoded Monero address from public keys
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*
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* @param string Public spend key
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* @param string Public view key
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*
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* @return string Base58 encoded Monero address
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*/
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public function encode_address($pSpendKey, $pViewKey)
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{
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// mainnet network byte is 18 (0x12)
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$data = "12" . $pSpendKey . $pViewKey;
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$encoded = $this->base58->encode($data);
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return $encoded;
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}
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public function verify_checksum($address)
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{
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$decoded = $this->base58->decode($address);
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$checksum = substr($decoded, -8);
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$checksum_hash = $this->keccak_256(substr($decoded, 0, 130));
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$calculated = substr($checksum_hash, 0, 8);
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if($checksum == $calculated){
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return true;
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}
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else
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return false;
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}
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/*
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* Decode a base58 encoded Monero address
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*
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* @param string A base58 encoded Monero address
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*
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* @return array An array containing the Address network byte, public spend key, and public view key
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*/
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public function decode_address($address)
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{
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$decoded = $this->base58->decode($address);
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if(!$this->verify_checksum($address)){
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throw new Exception("Error: invalid checksum");
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}
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$network_byte = substr($decoded, 0, 2);
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$public_spendKey = substr($decoded, 2, 64);
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$public_viewKey = substr($decoded, 66, 64);
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$result = array("networkByte" => $network_byte,
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"spendKey" => $public_spendKey,
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"viewKey" => $public_viewKey);
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return $result;
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}
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/*
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* Get an integrated address from public keys and a payment id
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*
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* @param string A 32 byte hex encoded public spend key
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* @param string A 32 byte hex encoded public view key
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* @param string An 8 byte hex string to use as a payment id
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*/
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public function integrated_addr_from_keys($public_spendkey, $public_viewkey, $payment_id)
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{
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// 0x13 is the mainnet network byte for integrated addresses
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$data = "13".$public_spendkey.$public_viewkey.$payment_id;
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$checksum = substr($this->keccak_256($data), 0, 8);
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$result = $this->base58->encode($data.$checksum);
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return $result;
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}
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/*
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* Generate a Monero address from seed
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*
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* @param string Hex string to use as seed
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*
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* @return string A base58 encoded Monero address
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*/
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public function address_from_seed($hex_seed)
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{
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$private_keys = $this->gen_private_keys($hex_seed);
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$private_viewKey = $private_keys["viewKey"];
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$private_spendKey = $private_keys["spendKey"];
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$public_spendKey = $this->pk_from_sk($private_spendKey);
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$public_viewKey = $this->pk_from_sk($private_viewKey);
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$address = $this->encode_address($public_spendKey, $public_viewKey);
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return $address;
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}
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}
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