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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/lib/crypto/curve25519.c
29267 views
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// SPDX-License-Identifier: GPL-2.0 OR MIT

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/*

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 * Copyright (C) 2015-2019 Jason A. Donenfeld <[email protected]>. All Rights Reserved.

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 *

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 * This is an implementation of the Curve25519 ECDH algorithm, using either an

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 * architecture-optimized implementation or a generic implementation. The

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 * generic implementation is either 32-bit, or 64-bit with 128-bit integers,

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 * depending on what is supported by the target compiler.

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 *

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 * Information: https://cr.yp.to/ecdh.html

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 */

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#include <crypto/curve25519.h>

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#include <crypto/utils.h>

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#include <linux/export.h>

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#include <linux/init.h>

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#include <linux/module.h>

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static const u8 curve25519_null_point[CURVE25519_KEY_SIZE] __aligned(32) = { 0 };

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static const u8 curve25519_base_point[CURVE25519_KEY_SIZE] __aligned(32) = { 9 };

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#ifdef CONFIG_CRYPTO_LIB_CURVE25519_ARCH

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#include "curve25519.h" /* $(SRCARCH)/curve25519.h */

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#else

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static void curve25519_arch(u8 mypublic[CURVE25519_KEY_SIZE],

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			    const u8 secret[CURVE25519_KEY_SIZE],

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			    const u8 basepoint[CURVE25519_KEY_SIZE])

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{

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	curve25519_generic(mypublic, secret, basepoint);

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}

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static void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],

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				 const u8 secret[CURVE25519_KEY_SIZE])

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{

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	curve25519_generic(pub, secret, curve25519_base_point);

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}

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#endif

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bool __must_check

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curve25519(u8 mypublic[CURVE25519_KEY_SIZE],

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	   const u8 secret[CURVE25519_KEY_SIZE],

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	   const u8 basepoint[CURVE25519_KEY_SIZE])

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{

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	curve25519_arch(mypublic, secret, basepoint);

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	return crypto_memneq(mypublic, curve25519_null_point,

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			     CURVE25519_KEY_SIZE);

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}

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EXPORT_SYMBOL(curve25519);

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bool __must_check

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curve25519_generate_public(u8 pub[CURVE25519_KEY_SIZE],

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			   const u8 secret[CURVE25519_KEY_SIZE])

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{

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	if (unlikely(!crypto_memneq(secret, curve25519_null_point,

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				    CURVE25519_KEY_SIZE)))

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		return false;

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	curve25519_base_arch(pub, secret);

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	return crypto_memneq(pub, curve25519_null_point, CURVE25519_KEY_SIZE);

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}

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EXPORT_SYMBOL(curve25519_generate_public);

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#ifdef curve25519_mod_init_arch

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static int __init curve25519_mod_init(void)

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{

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	curve25519_mod_init_arch();

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	return 0;

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}

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subsys_initcall(curve25519_mod_init);

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static void __exit curve25519_mod_exit(void)

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{

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}

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module_exit(curve25519_mod_exit);

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#endif

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MODULE_LICENSE("GPL v2");

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MODULE_DESCRIPTION("Curve25519 algorithm");

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MODULE_AUTHOR("Jason A. Donenfeld <[email protected]>");

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