bcrypt.html 24 KB

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  23. <h1 class="title">src/checksums/bcrypt</h1>
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  49. <li>
  50. <details open>
  51. <summary><a class="reference reference-toplevel" href="#7" id="57">Types</a></summary>
  52. <ul class="simple simple-toc-section">
  53. <li><a class="reference" href="#CostFactor" title="CostFactor = range[4 .. 31]">CostFactor</a></li>
  54. <li><a class="reference" href="#Hash" title="Hash = distinct HashBytes">Hash</a></li>
  55. <li><a class="reference" href="#Salt" title="Salt = object
  56. costFactor*: CostFactor">Salt</a></li>
  57. <li><a class="reference" href="#SaltedHash" title="SaltedHash = tuple[salt: Salt, hash: Hash]">SaltedHash</a></li>
  58. </ul>
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  62. <details open>
  63. <summary><a class="reference reference-toplevel" href="#12" id="62">Procs</a></summary>
  64. <ul class="simple simple-toc-section">
  65. <ul class="simple nested-toc-section">$
  66. <li><a class="reference" href="#%24%2CHash" title="`$`(s: Hash): string">`$`(s: Hash): string</a></li>
  67. <li><a class="reference" href="#%24%2CSalt" title="`$`(s: Salt): string">`$`(s: Salt): string</a></li>
  68. <li><a class="reference" href="#%24%2CSaltedHash" title="`$`(s: SaltedHash): string">`$`(s: SaltedHash): string</a></li>
  69. </ul>
  70. <ul class="simple nested-toc-section">bcrypt
  71. <li><a class="reference" href="#bcrypt%2CopenArray%5Bchar%5D%2CSalt" title="bcrypt(password: openArray[char]; salt: Salt): SaltedHash">bcrypt(password: openArray[char]; salt: Salt): SaltedHash</a></li>
  72. </ul>
  73. <ul class="simple nested-toc-section">generateSalt
  74. <li><a class="reference" href="#generateSalt%2CCostFactor" title="generateSalt(cost: CostFactor): Salt">generateSalt(cost: CostFactor): Salt</a></li>
  75. </ul>
  76. <ul class="simple nested-toc-section">parseSalt
  77. <li><a class="reference" href="#parseSalt%2Cstring" title="parseSalt(salt: string): Salt">parseSalt(salt: string): Salt</a></li>
  78. </ul>
  79. <ul class="simple nested-toc-section">verify
  80. <li><a class="reference" href="#verify%2CopenArray%5Bchar%5D%2Cstring" title="verify(password: openArray[char]; knownGood: string): bool">verify(password: openArray[char]; knownGood: string): bool</a></li>
  81. </ul>
  82. </ul>
  83. </details>
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  87. <div class="nine columns" id="content">
  88. <div id="tocRoot"></div>
  89. <p class="module-desc"><p><a class="reference external" href="https://en.wikipedia.org/wiki/Bcrypt">bcrypt</a> is a <a class="reference external" href="https://en.wikipedia.org/wiki/Blowfish_(cipher)">Blowfish</a>-based password hashing algorithm that is designed to be adaptively expensive to provide resistance against brute force based attacks and additionally includes a salt for lookup table resistance.</p>
  90. <p>Although bcrypt has been around for a long time, dating back to 1999, for many projects it is still a reasonable choice due to its adjustable cost factor that can provide security against all but the most well funded attackers.</p>
  91. <p>This module's design is based loosely on Python's <tt class="docutils literal"><span class="pre"><span class="Identifier">bcrypt</span></span></tt> module and supports generating the newer version <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">b</span></span></tt> hashes as well as verifying the older <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">a</span></span></tt> and the PHP equivalent of <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">b</span></span></tt> called <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">y</span></span></tt>.</p>
  92. <p><strong class="examples_text">Example:</strong></p>
  93. <pre class="listing"><span class="Keyword">import</span> <span class="Identifier">src</span><span class="Operator">/</span><span class="Identifier">checksums</span><span class="Operator">/</span><span class="Identifier">bcrypt</span>
  94. <span class="Comment"># Generate a salt with a specific cost factor and use it to hash a password.</span>
  95. <span class="Keyword">let</span> <span class="Identifier">hashed</span> <span class="Operator">=</span> <span class="Identifier">bcrypt</span><span class="Punctuation">(</span><span class="StringLit">&quot;correct horse battery stape&quot;</span><span class="Punctuation">,</span> <span class="Identifier">generateSalt</span><span class="Punctuation">(</span><span class="DecNumber">8</span><span class="Punctuation">)</span><span class="Punctuation">)</span></pre>
  96. <p><strong class="examples_text">Example:</strong></p>
  97. <pre class="listing"><span class="Keyword">import</span> <span class="Identifier">src</span><span class="Operator">/</span><span class="Identifier">checksums</span><span class="Operator">/</span><span class="Identifier">bcrypt</span>
  98. <span class="Comment"># Verify a password against a known good hash from i.e. a database.</span>
  99. <span class="Keyword">let</span> <span class="Identifier">knownGood</span> <span class="Operator">=</span> <span class="StringLit">&quot;$2b$06$LzUyyYdKBoEy9V4NTvxDH.O11KQP30/Zyp5pQAQ.0Cy89WnkD5Jjy&quot;</span>
  100. <span class="Identifier">assert</span> <span class="Identifier">verify</span><span class="Punctuation">(</span><span class="StringLit">&quot;correct horse battery staple&quot;</span><span class="Punctuation">,</span> <span class="Identifier">knownGood</span><span class="Punctuation">)</span></pre></p>
  101. <div class="section" id="7">
  102. <h1><a class="toc-backref" href="#7">Types</a></h1>
  103. <dl class="item">
  104. <div id="CostFactor">
  105. <dt><pre><a href="bcrypt.html#CostFactor"><span class="Identifier">CostFactor</span></a> <span class="Other">=</span> <span class="Identifier">range</span><span class="Other">[</span><span class="DecNumber">4</span> <span class="Operator">..</span> <span class="DecNumber">31</span><span class="Other">]</span></pre></dt>
  106. <dd>
  107. Adjustable cost factor. The value is a logarithm of 2, which means that a cost of 5 is twice as expensive as a cost of 4, and a cost of 16 is 2048 times more expensive than a cost of 5.
  108. </dd>
  109. </div>
  110. <div id="Hash">
  111. <dt><pre><a href="bcrypt.html#Hash"><span class="Identifier">Hash</span></a> <span class="Other">=</span> <span class="Keyword">distinct</span> <span class="Identifier">HashBytes</span></pre></dt>
  112. <dd>
  113. A 192 bit hash value produced by the <tt class="docutils literal"><span class="pre"><span class="Identifier">bcrypt</span></span></tt> function.
  114. </dd>
  115. </div>
  116. <div id="Salt">
  117. <dt><pre><a href="bcrypt.html#Salt"><span class="Identifier">Salt</span></a> <span class="Other">=</span> <span class="Keyword">object</span>
  118. <span class="Identifier">costFactor</span><span class="Operator">*</span><span class="Other">:</span> <a href="bcrypt.html#CostFactor"><span class="Identifier">CostFactor</span></a></pre></dt>
  119. <dd>
  120. A random 128 bit salt used to provide security against rainbow table attacks that also includes the bcrypt version and cost factor.
  121. </dd>
  122. </div>
  123. <div id="SaltedHash">
  124. <dt><pre><a href="bcrypt.html#SaltedHash"><span class="Identifier">SaltedHash</span></a> <span class="Other">=</span> <span class="Keyword">tuple</span><span class="Other">[</span><span class="Identifier">salt</span><span class="Other">:</span> <a href="bcrypt.html#Salt"><span class="Identifier">Salt</span></a><span class="Other">,</span> <span class="Identifier">hash</span><span class="Other">:</span> <a href="bcrypt.html#Hash"><span class="Identifier">Hash</span></a><span class="Other">]</span></pre></dt>
  125. <dd>
  126. </dd>
  127. </div>
  128. </dl>
  129. </div>
  130. <div class="section" id="12">
  131. <h1><a class="toc-backref" href="#12">Procs</a></h1>
  132. <dl class="item">
  133. <div id="$-procs-all">
  134. <div id="$,Hash">
  135. <dt><pre><span class="Keyword">proc</span> <a href="#%24%2CHash"><span class="Identifier">`$`</span></a><span class="Other">(</span><span class="Identifier">s</span><span class="Other">:</span> <a href="bcrypt.html#Hash"><span class="Identifier">Hash</span></a><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">string</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
  136. <dd>
  137. Renders the given <tt class="docutils literal"><span class="pre"><span class="Identifier">Hash</span></span></tt> into the canonical bcrypt-type Base64 representation.
  138. </dd>
  139. </div>
  140. <div id="$,Salt">
  141. <dt><pre><span class="Keyword">proc</span> <a href="#%24%2CSalt"><span class="Identifier">`$`</span></a><span class="Other">(</span><span class="Identifier">s</span><span class="Other">:</span> <a href="bcrypt.html#Salt"><span class="Identifier">Salt</span></a><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">string</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
  142. <dd>
  143. Renders the given <tt class="docutils literal"><span class="pre"><span class="Identifier">Salt</span></span></tt> into the canonical bcrypt-type Base64 representation along with its version and cost factor information.
  144. </dd>
  145. </div>
  146. <div id="$,SaltedHash">
  147. <dt><pre><span class="Keyword">proc</span> <a href="#%24%2CSaltedHash"><span class="Identifier">`$`</span></a><span class="Other">(</span><span class="Identifier">s</span><span class="Other">:</span> <a href="bcrypt.html#SaltedHash"><span class="Identifier">SaltedHash</span></a><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">string</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
  148. <dd>
  149. Renders the given <tt class="docutils literal"><span class="pre"><span class="Identifier">SaltedHash</span></span></tt> into the canonical bcrypt-type Base64 representation resulting in the actual hash string to be stored.
  150. </dd>
  151. </div>
  152. </div>
  153. <div id="bcrypt-procs-all">
  154. <div id="bcrypt,openArray[char],Salt">
  155. <dt><pre><span class="Keyword">proc</span> <a href="#bcrypt%2CopenArray%5Bchar%5D%2CSalt"><span class="Identifier">bcrypt</span></a><span class="Other">(</span><span class="Identifier">password</span><span class="Other">:</span> <span class="Identifier">openArray</span><span class="Other">[</span><span class="Identifier">char</span><span class="Other">]</span><span class="Other">;</span> <span class="Identifier">salt</span><span class="Other">:</span> <a href="bcrypt.html#Salt"><span class="Identifier">Salt</span></a><span class="Other">)</span><span class="Other">:</span> <a href="bcrypt.html#SaltedHash"><span class="Identifier">SaltedHash</span></a> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span>
  156. <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
  157. <dd>
  158. <p>Produces a <tt class="docutils literal"><span class="pre"><span class="Identifier">SaltedHash</span></span></tt> from the given password string and salt.</p>
  159. <p>Be careful when accepting a salt from a source outside of your control as a malicious user could pass in salts with a very high cost factor, resulting in denial of service attack.</p>
  160. <p><strong class="examples_text">Example:</strong></p>
  161. <pre class="listing"><span class="Keyword">let</span> <span class="Identifier">hashed</span> <span class="Operator">=</span> <span class="Identifier">bcrypt</span><span class="Punctuation">(</span><span class="StringLit">&quot;correct horse battery stape&quot;</span><span class="Punctuation">,</span> <span class="Identifier">generateSalt</span><span class="Punctuation">(</span><span class="DecNumber">8</span><span class="Punctuation">)</span><span class="Punctuation">)</span></pre>
  162. </dd>
  163. </div>
  164. </div>
  165. <div id="generateSalt-procs-all">
  166. <div id="generateSalt,CostFactor">
  167. <dt><pre><span class="Keyword">proc</span> <a href="#generateSalt%2CCostFactor"><span class="Identifier">generateSalt</span></a><span class="Other">(</span><span class="Identifier">cost</span><span class="Other">:</span> <a href="bcrypt.html#CostFactor"><span class="Identifier">CostFactor</span></a><span class="Other">)</span><span class="Other">:</span> <a href="bcrypt.html#Salt"><span class="Identifier">Salt</span></a> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Identifier">ResourceExhaustedError</span><span class="Other">,</span>
  168. <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
  169. <dd>
  170. Generates a new, random salt with the provided <tt class="docutils literal"><span class="pre"><span class="Identifier">CostFactor</span></span></tt>. Only salts with subversion <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">b</span></span></tt> are generated since it's the newest and default version of the reference bcrypt implementation.
  171. </dd>
  172. </div>
  173. </div>
  174. <div id="parseSalt-procs-all">
  175. <div id="parseSalt,string">
  176. <dt><pre><span class="Keyword">proc</span> <a href="#parseSalt%2Cstring"><span class="Identifier">parseSalt</span></a><span class="Other">(</span><span class="Identifier">salt</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <a href="bcrypt.html#Salt"><span class="Identifier">Salt</span></a> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Identifier">ValueError</span><span class="Other">,</span> <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
  177. <dd>
  178. <p>Parses a <tt class="docutils literal"><span class="pre"><span class="Identifier">Salt</span></span></tt> from the given string (which may be a full bcrypt hash or only the preamble).</p>
  179. <p>It accepts the <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">a</span></span></tt>, <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">b</span></span></tt> and <tt class="docutils literal"><span class="pre"><span class="DecNumber">2</span><span class="Identifier">y</span></span></tt> subversions.</p>
  180. <p><strong class="examples_text">Example:</strong></p>
  181. <pre class="listing"><span class="Comment"># Parse full hash</span>
  182. <span class="Keyword">let</span> <span class="Identifier">salt1</span> <span class="Operator">=</span> <span class="Identifier">parseSalt</span> <span class="StringLit">&quot;$2b$06$LzUyyYdKBoEy9V4NTvxDH.&quot;</span>
  183. <span class="Comment"># Parse salt part</span>
  184. <span class="Keyword">let</span> <span class="Identifier">salt2</span> <span class="Operator">=</span> <span class="Identifier">parseSalt</span> <span class="StringLit">&quot;$2b$06$LzUyyYdKBoEy9V4NTvxDH.PvwrAArbP0DUvDUFf8ChnJl6/79lh3C&quot;</span>
  185. <span class="Identifier">assert</span> <span class="Operator">$</span><span class="Identifier">salt1</span> <span class="Operator">==</span> <span class="StringLit">&quot;$2b$06$LzUyyYdKBoEy9V4NTvxDH.&quot;</span>
  186. <span class="Identifier">assert</span> <span class="Operator">$</span><span class="Identifier">salt2</span> <span class="Operator">==</span> <span class="StringLit">&quot;$2b$06$LzUyyYdKBoEy9V4NTvxDH.&quot;</span></pre>
  187. </dd>
  188. </div>
  189. </div>
  190. <div id="verify-procs-all">
  191. <div id="verify,openArray[char],string">
  192. <dt><pre><span class="Keyword">proc</span> <a href="#verify%2CopenArray%5Bchar%5D%2Cstring"><span class="Identifier">verify</span></a><span class="Other">(</span><span class="Identifier">password</span><span class="Other">:</span> <span class="Identifier">openArray</span><span class="Other">[</span><span class="Identifier">char</span><span class="Other">]</span><span class="Other">;</span> <span class="Identifier">knownGood</span><span class="Other">:</span> <span class="Identifier">string</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">bool</span> {.
  193. <span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Identifier">ValueError</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span> <span class="Identifier">forbids</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
  194. <dd>
  195. <p>Verifies a given plaintext password against a hash from a known good source such as a database or other data storage.</p>
  196. <p>Be careful when accepting a hash from a source outside of your control as a malicious user could pass salts with a very high cost factor, resulting in denial of service attack.</p>
  197. <p><strong class="examples_text">Example:</strong></p>
  198. <pre class="listing"><span class="Keyword">let</span> <span class="Identifier">knownGood</span> <span class="Operator">=</span> <span class="StringLit">&quot;$2b$06$LzUyyYdKBoEy9V4NTvxDH.O11KQP30/Zyp5pQAQ.0Cy89WnkD5Jjy&quot;</span>
  199. <span class="Identifier">assert</span> <span class="Identifier">verify</span><span class="Punctuation">(</span><span class="StringLit">&quot;correct horse battery staple&quot;</span><span class="Punctuation">,</span> <span class="Identifier">knownGood</span><span class="Punctuation">)</span></pre>
  200. </dd>
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