Complex classes like RSAKey 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 RSAKey, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
            ||
| 25 | final class RSAKey extends Sequence  | 
            ||
| 26 | { | 
            ||
| 27 | /**  | 
            ||
| 28 | * @var array  | 
            ||
| 29 | */  | 
            ||
| 30 | private $values = [];  | 
            ||
| 31 | |||
| 32 | /**  | 
            ||
| 33 | * @var \Jose\Util\BigInteger  | 
            ||
| 34 | */  | 
            ||
| 35 | private $modulus;  | 
            ||
| 36 | |||
| 37 | /**  | 
            ||
| 38 | * @var int  | 
            ||
| 39 | */  | 
            ||
| 40 | private $modulus_length;  | 
            ||
| 41 | |||
| 42 | /**  | 
            ||
| 43 | * @var \Jose\Util\BigInteger  | 
            ||
| 44 | */  | 
            ||
| 45 | private $public_exponent;  | 
            ||
| 46 | |||
| 47 | /**  | 
            ||
| 48 | * @var \Jose\Util\BigInteger|null  | 
            ||
| 49 | */  | 
            ||
| 50 | private $private_exponent = null;  | 
            ||
| 51 | |||
| 52 | /**  | 
            ||
| 53 | * @var \Jose\Util\BigInteger[]  | 
            ||
| 54 | */  | 
            ||
| 55 | private $primes = [];  | 
            ||
| 56 | |||
| 57 | /**  | 
            ||
| 58 | * @var \Jose\Util\BigInteger[]  | 
            ||
| 59 | */  | 
            ||
| 60 | private $exponents = [];  | 
            ||
| 61 | |||
| 62 | /**  | 
            ||
| 63 | * @var \Jose\Util\BigInteger|null  | 
            ||
| 64 | */  | 
            ||
| 65 | private $coefficient = null;  | 
            ||
| 66 | |||
| 67 | |||
| 68 | /**  | 
            ||
| 69 | * @param \Jose\Object\JWKInterface|string|array $data  | 
            ||
| 70 | */  | 
            ||
| 71 | public function __construct($data)  | 
            ||
| 87 | |||
| 88 | /**  | 
            ||
| 89 | * @return bool  | 
            ||
| 90 | */  | 
            ||
| 91 | public function isPublic()  | 
            ||
| 95 | |||
| 96 | /**  | 
            ||
| 97 | * @return bool  | 
            ||
| 98 | */  | 
            ||
| 99 | public function isPrivate()  | 
            ||
| 103 | |||
| 104 | /**  | 
            ||
| 105 | * @return \Jose\Util\BigInteger  | 
            ||
| 106 | */  | 
            ||
| 107 | public function getModulus()  | 
            ||
| 111 | |||
| 112 | /**  | 
            ||
| 113 | * @return int  | 
            ||
| 114 | */  | 
            ||
| 115 | public function getModulusLength()  | 
            ||
| 119 | |||
| 120 | /**  | 
            ||
| 121 | * @return \Jose\Util\BigInteger  | 
            ||
| 122 | */  | 
            ||
| 123 | public function getExponent()  | 
            ||
| 132 | |||
| 133 | /**  | 
            ||
| 134 | * @return \Jose\Util\BigInteger  | 
            ||
| 135 | */  | 
            ||
| 136 | public function getPublicExponent()  | 
            ||
| 140 | |||
| 141 | /**  | 
            ||
| 142 | * @return \Jose\Util\BigInteger  | 
            ||
| 143 | */  | 
            ||
| 144 | public function getPrivateExponent()  | 
            ||
| 148 | |||
| 149 | /**  | 
            ||
| 150 | * @return \Jose\Util\BigInteger[]  | 
            ||
| 151 | */  | 
            ||
| 152 | public function getPrimes()  | 
            ||
| 156 | |||
| 157 | /**  | 
            ||
| 158 | * @return \Jose\Util\BigInteger[]  | 
            ||
| 159 | */  | 
            ||
| 160 | public function getExponents()  | 
            ||
| 164 | |||
| 165 | /**  | 
            ||
| 166 | * @return \Jose\Util\BigInteger|null  | 
            ||
| 167 | */  | 
            ||
| 168 | public function getCoefficient()  | 
            ||
| 172 | |||
| 173 | /**  | 
            ||
| 174 | * @param \Jose\KeyConverter\RSAKey $private  | 
            ||
| 175 | *  | 
            ||
| 176 | * @return \Jose\KeyConverter\RSAKey  | 
            ||
| 177 | */  | 
            ||
| 178 | public static function toPublic(RSAKey $private)  | 
            ||
| 190 | |||
| 191 | public function __toString()  | 
            ||
| 195 | |||
| 196 | /**  | 
            ||
| 197 | * @return array  | 
            ||
| 198 | */  | 
            ||
| 199 | public function toArray()  | 
            ||
| 203 | |||
| 204 | /**  | 
            ||
| 205 | * @return string  | 
            ||
| 206 | */  | 
            ||
| 207 | public function toDER()  | 
            ||
| 211 | |||
| 212 | /**  | 
            ||
| 213 | * @return string  | 
            ||
| 214 | */  | 
            ||
| 215 | public function toPEM()  | 
            ||
| 223 | |||
| 224 | /**  | 
            ||
| 225 | * @param string $data  | 
            ||
| 226 | *  | 
            ||
| 227 | * @throws \Exception  | 
            ||
| 228 | * @throws \FG\ASN1\Exception\ParserException  | 
            ||
| 229 | *  | 
            ||
| 230 | * @return array  | 
            ||
| 231 | */  | 
            ||
| 232 | private function loadPEM($data)  | 
            ||
| 261 | |||
| 262 | /**  | 
            ||
| 263 | * @param array $jwk  | 
            ||
| 264 | */  | 
            ||
| 265 | private function loadJWK(array $jwk)  | 
            ||
| 278 | |||
| 279 | /**  | 
            ||
| 280 | * This method adds Chinese Remainder Theorem (CRT) parameters if primes 'p' and 'q' are available.  | 
            ||
| 281 | */  | 
            ||
| 282 | private function populateCRT()  | 
            ||
| 300 | |||
| 301 | /**  | 
            ||
| 302 | * @throws \Exception  | 
            ||
| 303 | */  | 
            ||
| 304 | private function initPublicKey()  | 
            ||
| 320 | |||
| 321 | private function initPrivateKey()  | 
            ||
| 353 | |||
| 354 | /**  | 
            ||
| 355 | * @param string $value  | 
            ||
| 356 | *  | 
            ||
| 357 | * @return string  | 
            ||
| 358 | */  | 
            ||
| 359 | private function fromBase64ToInteger($value)  | 
            ||
| 363 | |||
| 364 | private function populateBigIntegers()  | 
            ||
| 386 | |||
| 387 | /**  | 
            ||
| 388 | * @param string $value  | 
            ||
| 389 | *  | 
            ||
| 390 | * @return \Jose\Util\BigInteger  | 
            ||
| 391 | */  | 
            ||
| 392 | private function convertBase64StringToBigInteger($value)  | 
            ||
| 396 | }  | 
            ||
| 397 |