Complex classes like RSA 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 RSA, and based on these observations, apply Extract Interface, too.
1 | <?php |
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17 | final class RSA |
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18 | { |
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19 | /** |
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20 | * ASN1 Integer. |
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21 | */ |
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22 | const ASN1_INTEGER = 2; |
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23 | |||
24 | /** |
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25 | * ASN1 Bit String. |
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26 | */ |
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27 | const ASN1_BITSTRING = 3; |
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28 | |||
29 | /** |
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30 | * ASN1 Octet String. |
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31 | */ |
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32 | const ASN1_OCTETSTRING = 4; |
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33 | |||
34 | /** |
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35 | * ASN1 Object Identifier. |
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36 | */ |
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37 | const ASN1_OBJECT = 6; |
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38 | |||
39 | /** |
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40 | * ASN1 Sequence (with the constucted bit set). |
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41 | */ |
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42 | const ASN1_SEQUENCE = 48; |
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43 | |||
44 | /** |
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45 | * To use the pure-PHP implementation. |
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46 | */ |
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47 | const MODE_INTERNAL = 1; |
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48 | |||
49 | /** |
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50 | * To use the OpenSSL library. |
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51 | */ |
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52 | const MODE_OPENSSL = 2; |
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53 | |||
54 | /** |
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55 | * PKCS#1 formatted private key. |
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56 | */ |
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57 | const PRIVATE_FORMAT_PKCS1 = 0; |
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58 | |||
59 | /** |
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60 | * PuTTY formatted private key. |
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61 | */ |
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62 | const PRIVATE_FORMAT_PUTTY = 1; |
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63 | |||
64 | /** |
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65 | * XML formatted private key. |
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66 | */ |
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67 | const PRIVATE_FORMAT_XML = 2; |
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68 | |||
69 | /** |
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70 | * PKCS#8 formatted private key. |
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71 | */ |
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72 | const PRIVATE_FORMAT_PKCS8 = 8; |
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73 | |||
74 | /** |
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75 | * Raw public key. |
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76 | */ |
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77 | const PUBLIC_FORMAT_RAW = 3; |
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78 | |||
79 | /** |
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80 | * PKCS#1 formatted public key (raw). |
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81 | */ |
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82 | const PUBLIC_FORMAT_PKCS1 = 4; |
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83 | |||
84 | /** |
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85 | * Precomputed Zero. |
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86 | * |
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87 | * @var \Jose\Util\BigInteger |
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88 | */ |
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89 | private $zero; |
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90 | |||
91 | /** |
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92 | * Precomputed One. |
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93 | * |
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94 | * @var \Jose\Util\BigInteger |
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95 | */ |
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96 | private $one; |
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97 | |||
98 | /** |
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99 | * Modulus (ie. n). |
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100 | * |
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101 | * @var \Jose\Util\BigInteger |
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102 | */ |
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103 | private $modulus; |
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104 | |||
105 | /** |
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106 | * Modulus length. |
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107 | * |
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108 | * @var int |
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109 | */ |
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110 | private $k; |
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111 | |||
112 | /** |
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113 | * Exponent (ie. e or d). |
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114 | * |
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115 | * @var \Jose\Util\BigInteger |
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116 | */ |
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117 | private $exponent; |
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118 | |||
119 | /** |
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120 | * Primes for Chinese Remainder Theorem (ie. p and q). |
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121 | * |
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122 | * @var \Jose\Util\BigInteger[] |
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123 | */ |
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124 | private $primes; |
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125 | |||
126 | /** |
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127 | * Exponents for Chinese Remainder Theorem (ie. dP and dQ). |
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128 | * |
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129 | * @var \Jose\Util\BigInteger[] |
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130 | */ |
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131 | private $exponents; |
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132 | |||
133 | /** |
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134 | * Coefficients for Chinese Remainder Theorem (ie. qInv). |
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135 | * |
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136 | * @var \Jose\Util\BigInteger[] |
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137 | */ |
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138 | private $coefficients; |
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139 | |||
140 | /** |
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141 | * Hash function. |
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142 | * |
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143 | * @var \Jose\Util\Hash |
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144 | */ |
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145 | private $hash; |
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146 | |||
147 | /** |
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148 | * Length of salt. |
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149 | * |
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150 | * @var int |
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151 | */ |
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152 | private $sLen; |
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153 | |||
154 | /** |
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155 | * Hash function for the Mask Generation Function. |
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156 | * |
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157 | * @var \Jose\Util\Hash |
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158 | */ |
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159 | private $mgfHash; |
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160 | |||
161 | /** |
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162 | * Public Exponent. |
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163 | * |
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164 | * @var mixed |
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165 | */ |
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166 | private $publicExponent = false; |
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167 | |||
168 | /** |
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169 | * RSA constructor. |
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170 | */ |
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171 | public function __construct() |
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179 | |||
180 | /** |
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181 | * Loads a public or private key. |
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182 | * |
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183 | * @param \Jose\Object\JWKInterface $key |
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184 | */ |
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185 | public function loadKey(JWKInterface $key) |
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216 | |||
217 | /** |
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218 | * Determines which hashing function should be used. |
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219 | * |
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220 | * @param string $hash |
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221 | */ |
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222 | public function setHash($hash) |
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226 | |||
227 | /** |
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228 | * Determines which hashing function should be used for the mask generation function. |
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229 | * |
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230 | * @param string $hash |
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231 | */ |
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232 | public function setMGFHash($hash) |
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236 | |||
237 | /** |
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238 | * Determines the salt length. |
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239 | * |
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240 | * @param int $sLen |
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241 | */ |
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242 | public function setSaltLength($sLen) |
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246 | |||
247 | /** |
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248 | * Integer-to-Octet-String primitive. |
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249 | * |
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250 | * @param \Jose\Util\BigInteger $x |
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251 | * @param int $xLen |
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252 | * |
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253 | * @return string |
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254 | */ |
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255 | private function _i2osp($x, $xLen) |
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265 | |||
266 | /** |
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267 | * Octet-String-to-Integer primitive. |
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268 | * |
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269 | * @param string $x |
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270 | * |
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271 | * @return \Jose\Util\BigInteger |
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272 | */ |
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273 | private function _os2ip($x) |
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277 | |||
278 | /** |
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279 | * Exponentiate with or without Chinese Remainder Theorem. |
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280 | * |
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281 | * @param \Jose\Util\BigInteger $x |
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282 | * |
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283 | * @return \Jose\Util\BigInteger |
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284 | */ |
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285 | private function _exponentiate($x) |
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328 | |||
329 | /** |
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330 | * Performs RSA Blinding. |
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331 | * |
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332 | * @param \Jose\Util\BigInteger $x |
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333 | * @param \Jose\Util\BigInteger $r |
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334 | * @param int $i |
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335 | * |
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336 | * @return \Jose\Util\BigInteger |
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337 | */ |
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338 | private function _blind($x, $r, $i) |
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349 | |||
350 | /** |
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351 | * Performs blinded RSA equality testing. |
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352 | * |
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353 | * @param string $x |
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354 | * @param string $y |
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355 | * |
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356 | * @return bool |
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357 | */ |
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358 | private function _equals($x, $y) |
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371 | |||
372 | /** |
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373 | * RSAEP. |
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374 | * |
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375 | * @param \Jose\Util\BigInteger $m |
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376 | * |
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377 | * @return \Jose\Util\BigInteger |
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378 | */ |
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379 | private function _rsaep($m) |
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388 | |||
389 | /** |
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390 | * RSADP. |
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391 | * |
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392 | * @param \Jose\Util\BigInteger $c |
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393 | * |
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394 | * @return \Jose\Util\BigInteger |
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395 | */ |
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396 | private function _rsadp($c) |
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405 | |||
406 | /** |
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407 | * RSASP1. |
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408 | * |
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409 | * @param \Jose\Util\BigInteger $m |
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410 | * |
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411 | * @return \Jose\Util\BigInteger |
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412 | */ |
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413 | private function _rsasp1($m) |
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422 | |||
423 | /** |
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424 | * RSAVP1. |
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425 | * |
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426 | * @param \Jose\Util\BigInteger $s |
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427 | * |
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428 | * @return \Jose\Util\BigInteger |
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429 | */ |
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430 | private function _rsavp1($s) |
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439 | |||
440 | /** |
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441 | * MGF1. |
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442 | * |
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443 | * @param string $mgfSeed |
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444 | * @param int $maskLen |
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445 | * |
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446 | * @return string |
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447 | */ |
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448 | private function _mgf1($mgfSeed, $maskLen) |
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461 | |||
462 | /** |
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463 | * RSAES-OAEP-ENCRYPT. |
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464 | * |
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465 | * @param string $m |
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466 | * @param string $l |
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467 | * |
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468 | * @return string |
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469 | */ |
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470 | private function _rsaes_oaep_encrypt($m, $l = '') |
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506 | |||
507 | /** |
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508 | * RSAES-OAEP-DECRYPT. |
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509 | * |
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510 | * @param string $c |
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511 | * @param string $l |
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512 | * |
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513 | * @return string |
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514 | */ |
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515 | private function _rsaes_oaep_decrypt($c, $l = '') |
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563 | |||
564 | /** |
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565 | * EMSA-PSS-ENCODE. |
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566 | * |
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567 | * @param string $m |
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568 | * @param int $emBits |
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569 | * |
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570 | * @return bool |
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571 | */ |
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572 | private function _emsa_pss_encode($m, $emBits) |
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598 | |||
599 | /** |
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600 | * EMSA-PSS-VERIFY. |
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601 | * |
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602 | * @param string $m |
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603 | * @param string $em |
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604 | * @param int $emBits |
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605 | * |
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606 | * @return string |
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607 | */ |
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608 | private function _emsa_pss_verify($m, $em, $emBits) |
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644 | |||
645 | /** |
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646 | * RSASSA-PSS-SIGN. |
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647 | * |
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648 | * @param string $m |
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649 | * |
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650 | * @return string |
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651 | */ |
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652 | private function _rsassa_pss_sign($m) |
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668 | |||
669 | /** |
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670 | * RSASSA-PSS-VERIFY. |
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671 | * |
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672 | * @param string $m |
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673 | * @param string $s |
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674 | * |
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675 | * @return string |
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676 | */ |
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677 | private function _rsassa_pss_verify($m, $s) |
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706 | |||
707 | /** |
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708 | * Encryption. |
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709 | * |
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710 | * Both self::ENCRYPTION_OAEP and self::ENCRYPTION_PKCS1 both place limits on how long $plaintext can be. |
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711 | * If $plaintext exceeds those limits it will be broken up so that it does and the resultant ciphertext's will |
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712 | * be concatenated together. |
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713 | * |
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714 | * @see self::decrypt() |
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715 | * |
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716 | * @param string $plaintext |
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717 | * |
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718 | * @return string |
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719 | */ |
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720 | public function encrypt($plaintext) |
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735 | |||
736 | /** |
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737 | * Decryption. |
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738 | * |
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739 | * @param string $ciphertext |
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740 | * |
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741 | * @return string |
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742 | */ |
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743 | public function decrypt($ciphertext) |
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764 | |||
765 | /** |
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766 | * Create a signature. |
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767 | * |
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768 | * @param string $message |
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769 | * |
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770 | * @return string |
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771 | */ |
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772 | public function sign($message) |
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781 | |||
782 | /** |
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783 | * Verifies a signature. |
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784 | * |
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785 | * @param string $message |
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786 | * @param string $signature |
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787 | * |
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788 | * @return bool |
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789 | */ |
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790 | public function verify($message, $signature) |
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798 | } |
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799 |