Complex classes like Curve often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Curve, and based on these observations, apply Extract Interface, too.
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23 | final class Curve |
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24 | { |
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25 | /** |
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26 | * Elliptic curve over the field of integers modulo a prime. |
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27 | * |
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28 | * @var \GMP |
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29 | */ |
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30 | private $a; |
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31 | |||
32 | /** |
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33 | * @var \GMP |
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34 | */ |
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35 | private $b; |
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36 | |||
37 | /** |
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38 | * @var \GMP |
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39 | */ |
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40 | private $prime; |
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41 | |||
42 | /** |
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43 | * Binary length of keys associated with these curve parameters. |
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44 | * |
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45 | * @var int |
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46 | */ |
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47 | private $size; |
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48 | |||
49 | /** |
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50 | * @var Point |
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51 | */ |
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52 | private $generator; |
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53 | |||
54 | /** |
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55 | * @param int $size |
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56 | * @param \GMP $prime |
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57 | * @param \GMP $a |
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58 | * @param \GMP $b |
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59 | * @param Point $generator |
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60 | */ |
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61 | public function __construct(int $size, \GMP $prime, \GMP $a, \GMP $b, Point $generator) |
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69 | |||
70 | /** |
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71 | * @return \GMP |
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72 | */ |
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73 | public function getA(): \GMP |
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77 | |||
78 | /** |
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79 | * @return \GMP |
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80 | */ |
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81 | public function getB(): \GMP |
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85 | |||
86 | /** |
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87 | * @return \GMP |
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88 | */ |
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89 | public function getPrime(): \GMP |
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93 | |||
94 | /** |
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95 | * @return int |
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96 | */ |
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97 | public function getSize(): int |
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101 | |||
102 | /** |
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103 | * @param \GMP $x |
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104 | * @param \GMP $y |
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105 | * @param \GMP|null $order |
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106 | * |
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107 | * @return Point |
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108 | */ |
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109 | public function getPoint(\GMP $x, \GMP $y, ?\GMP $order = null): Point |
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124 | |||
125 | /** |
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126 | * @param \GMP $x |
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127 | * @param \GMP $y |
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128 | * |
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129 | * @return PublicKey |
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130 | */ |
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131 | public function getPublicKeyFrom(\GMP $x, \GMP $y): PublicKey |
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141 | |||
142 | /** |
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143 | * @param \GMP $x |
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144 | * @param \GMP $y |
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145 | * |
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146 | * @return bool |
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147 | */ |
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148 | public function contains(\GMP $x, \GMP $y): bool |
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167 | |||
168 | /** |
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169 | * @param Point $one |
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170 | * @param Point $two |
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171 | * |
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172 | * @return Point |
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173 | */ |
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174 | public function add(Point $one, Point $two): Point |
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212 | |||
213 | /** |
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214 | * @param Point $one |
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215 | * @param \GMP $n |
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216 | * |
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217 | * @return Point |
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218 | */ |
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219 | public function mul(Point $one, \GMP $n): Point |
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256 | |||
257 | /** |
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258 | * @param Curve $other |
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259 | * |
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260 | * @return int |
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261 | */ |
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262 | public function cmp(Curve $other): int |
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270 | |||
271 | /** |
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272 | * @param Curve $other |
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273 | * |
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274 | * @return bool |
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275 | */ |
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276 | public function equals(Curve $other): bool |
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280 | |||
281 | /** |
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282 | * @return string |
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283 | */ |
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284 | public function __toString(): string |
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288 | |||
289 | /** |
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290 | * @param Point $point |
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291 | */ |
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292 | private function validate(Point $point) |
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298 | |||
299 | /** |
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300 | * @param Point $point |
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301 | * |
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302 | * @return Point |
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303 | */ |
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304 | public function getDouble(Point $point): Point |
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333 | |||
334 | /** |
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335 | * @return PrivateKey |
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336 | */ |
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337 | public function createPrivateKey(): PrivateKey |
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341 | |||
342 | /** |
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343 | * @param PrivateKey $privateKey |
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344 | * |
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345 | * @return PublicKey |
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346 | */ |
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347 | public function createPublicKey(PrivateKey $privateKey): PublicKey |
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353 | |||
354 | /** |
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355 | * @return \GMP |
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356 | */ |
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357 | private function generate(): \GMP |
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370 | |||
371 | /** |
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372 | * Returns the number of bits used to store this number. Non-significant upper bits are not counted. |
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373 | * |
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374 | * @param \GMP $x |
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375 | * |
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376 | * @return int |
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377 | * |
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378 | * @see https://www.openssl.org/docs/crypto/BN_num_bytes.html |
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379 | */ |
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380 | private function bnNumBits(\GMP $x): int |
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394 | |||
395 | /** |
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396 | * @return Point |
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397 | */ |
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398 | public function getGenerator(): Point |
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402 | } |
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403 |