139 lines
5.8 KiB
HTML
Executable File
139 lines
5.8 KiB
HTML
Executable File
<?xml version="1.0" ?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<title>evp</title>
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<meta http-equiv="content-type" content="text/html; charset=utf-8" />
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<link rev="made" href="mailto:root@localhost" />
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</head>
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<body style="background-color: white">
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<!-- INDEX BEGIN -->
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<div name="index">
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<p><a name="__index__"></a></p>
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<ul>
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<li><a href="#name">NAME</a></li>
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<li><a href="#synopsis">SYNOPSIS</a></li>
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<li><a href="#description">DESCRIPTION</a></li>
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<li><a href="#see_also">SEE ALSO</a></li>
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<li><a href="#copyright">COPYRIGHT</a></li>
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</ul>
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<hr name="index" />
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</div>
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<!-- INDEX END -->
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<p>
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</p>
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<hr />
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<h1><a name="name">NAME</a></h1>
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<p>evp - high-level cryptographic functions</p>
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<p>
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</p>
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<hr />
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<h1><a name="synopsis">SYNOPSIS</a></h1>
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<pre>
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#include <openssl/evp.h></pre>
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<p>
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</p>
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<hr />
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<h1><a name="description">DESCRIPTION</a></h1>
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<p>The EVP library provides a high-level interface to cryptographic
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functions.</p>
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<p>The <em><strong>EVP_Seal</strong><em>XXX</em></em> and <em><strong>EVP_Open</strong><em>XXX</em></em>
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functions provide public key encryption and decryption to implement digital "envelopes".</p>
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<p>The <em><strong>EVP_DigestSign</strong><em>XXX</em></em> and
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<em><strong>EVP_DigestVerify</strong><em>XXX</em></em> functions implement
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digital signatures and Message Authentication Codes (MACs). Also see the older
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<em><strong>EVP_Sign</strong><em>XXX</em></em> and <em><strong>EVP_Verify</strong><em>XXX</em></em>
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functions.</p>
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<p>Symmetric encryption is available with the <em><strong>EVP_Encrypt</strong><em>XXX</em></em>
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functions. The <em><strong>EVP_Digest</strong><em>XXX</em></em> functions provide message digests.</p>
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<p>The <strong>EVP_PKEY</strong><em>XXX</em> functions provide a high level interface to
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asymmetric algorithms. To create a new EVP_PKEY see
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<em>EVP_PKEY_new(3)</em>. EVP_PKEYs can be associated
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with a private key of a particular algorithm by using the functions
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described on the <em>EVP_PKEY_set1_RSA(3)</em> page, or
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new keys can be generated using <em>EVP_PKEY_keygen(3)</em>.
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EVP_PKEYs can be compared using <em>EVP_PKEY_cmp(3)</em>, or printed using
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<em>EVP_PKEY_print_private(3)</em>.</p>
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<p>The EVP_PKEY functions support the full range of asymmetric algorithm operations:</p>
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<dl>
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<dt><strong><a name="evp_pkey_derive" class="item">For key agreement see <a href="#evp_pkey_derive">EVP_PKEY_derive(3)</a></a></strong></dt>
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<dt><strong><a name="evp_pkey_sign" class="item">For signing and verifying see <a href="#evp_pkey_sign">EVP_PKEY_sign(3)</a>,
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<em>EVP_PKEY_verify(3)</em> and <em>EVP_PKEY_verify_recover(3)</em>.
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However, note that
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these functions do not perform a digest of the data to be signed. Therefore
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normally you would use the <em>EVP_DigestSignInit(3)</em>
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functions for this purpose.</a></strong></dt>
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<dt><strong><a name="evp_pkey_encrypt" class="item">For encryption and decryption see <a href="#evp_pkey_encrypt">EVP_PKEY_encrypt(3)</a>
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and <em>EVP_PKEY_decrypt(3)</em> respectively. However, note that
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these functions perform encryption and decryption only. As public key
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encryption is an expensive operation, normally you would wrap
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an encrypted message in a "digital envelope" using the <em>EVP_SealInit(3)</em> and
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<em>EVP_OpenInit(3)</em> functions.</a></strong></dt>
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</dl>
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<p>The <em>EVP_BytesToKey(3)</em> function provides some limited support for password
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based encryption. Careful selection of the parameters will provide a PKCS#5 PBKDF1 compatible
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implementation. However, new applications should not typically use this (preferring, for example,
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PBKDF2 from PCKS#5).</p>
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<p>The <em><strong>EVP_Encode</strong><em>XXX</em></em> and
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<em><strong>EVP_Decode</strong><em>XXX</em></em> functions implement base 64 encoding
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and decoding.</p>
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<p>All the symmetric algorithms (ciphers), digests and asymmetric algorithms
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(public key algorithms) can be replaced by ENGINE modules providing alternative
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implementations. If ENGINE implementations of ciphers or digests are registered
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as defaults, then the various EVP functions will automatically use those
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implementations automatically in preference to built in software
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implementations. For more information, consult the <code>engine(3)</code> man page.</p>
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<p>Although low level algorithm specific functions exist for many algorithms
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their use is discouraged. They cannot be used with an ENGINE and ENGINE
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versions of new algorithms cannot be accessed using the low level functions.
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Also makes code harder to adapt to new algorithms and some options are not
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cleanly supported at the low level and some operations are more efficient
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using the high level interface.</p>
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<p>
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</p>
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<hr />
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<h1><a name="see_also">SEE ALSO</a></h1>
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<p><em>EVP_DigestInit(3)</em>,
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<em>EVP_EncryptInit(3)</em>,
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<em>EVP_OpenInit(3)</em>,
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<em>EVP_SealInit(3)</em>,
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<em>EVP_DigestSignInit(3)</em>,
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<em>EVP_SignInit(3)</em>,
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<em>EVP_VerifyInit(3)</em>,
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<em>EVP_EncodeInit(3)</em>,
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<em>EVP_PKEY_new(3)</em>,
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<em>EVP_PKEY_set1_RSA(3)</em>,
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<em>EVP_PKEY_keygen(3)</em>,
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<em>EVP_PKEY_print_private(3)</em>,
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<em>EVP_PKEY_decrypt(3)</em>,
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<a href="#evp_pkey_encrypt">EVP_PKEY_encrypt(3)</a>,
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<a href="#evp_pkey_sign">EVP_PKEY_sign(3)</a>,
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<em>EVP_PKEY_verify(3)</em>,
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<em>EVP_PKEY_verify_recover(3)</em>,
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<a href="#evp_pkey_derive">EVP_PKEY_derive(3)</a>,
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<em>EVP_BytesToKey(3)</em>,
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<em>ENGINE_by_id(3)</em></p>
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<p>
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</p>
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<hr />
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<h1><a name="copyright">COPYRIGHT</a></h1>
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<p>Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.</p>
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<p>Licensed under the Apache License 2.0 (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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<a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>
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</body>
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</html>
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