Skip to content
Snippets Groups Projects
Select Git revision
  • master
  • siv-mode
  • delete-des-compat
  • delete-rsa_blind
  • aes-struct-layout
  • master-updates
  • release-3.4-fixes
  • struct-layout
  • attribute-deprecated
  • rename-data-symbols
  • x86_64-sha_ni-sha256
  • ecc-params-tweak
  • delete-old-aes
  • cmac-support
  • x86_64-sha_ni-sha1
  • gcm-ctr-opt
  • ctr-opt
  • skein
  • api-opaque-fix
  • curve448
  • nettle_3.4.1_release_20181204
  • nettle_3.4.1rc1
  • nettle_3.4_release_20171119
  • nettle_3.4rc2
  • nettle_3.4rc1
  • nettle_3.3_release_20161001
  • nettle_3.2_release_20160128
  • nettle_3.1.1_release_20150424
  • nettle_3.1_release_20150407
  • nettle_3.1rc3
  • nettle_3.1rc2
  • nettle_3.1rc1
  • nettle_3.0_release_20140607
  • nettle_2.7.1_release_20130528
  • nettle_2.7_release_20130424
  • nettle_2.6_release_20130116
  • nettle_2.5_release_20120707
  • converted-master-branch-to-git
  • nettle_2.4_release_20110903
  • nettle_2.3_release_20110902
40 results

chacha.h

Blame
  • Forked from Nettle / nettle
    Source project has a limited visibility.
    • Nikos Mavrogiannopoulos's avatar
      da81c86a
      abi: explicitly export intended symbols and hide others · da81c86a
      Nikos Mavrogiannopoulos authored and Niels Möller's avatar Niels Möller committed
      This adds all exported symbols in the map files explicitly under
      the following rules:
       - Symbols mentioned in internal headers go in a section which is
         valid only for testing, and linking with these symbols will break
         in library updates.
       - Symbols mentioned in installed headers go in the exported sections
         and are considered part of the ABI.
       - All internal symbols move to internal headers.
       - The _nettle_md5_compress and _nettle_sha1_compress become exported
         without the _nettle prefix, due to existing usage.
      da81c86a
      History
      abi: explicitly export intended symbols and hide others
      Nikos Mavrogiannopoulos authored and Niels Möller's avatar Niels Möller committed
      This adds all exported symbols in the map files explicitly under
      the following rules:
       - Symbols mentioned in internal headers go in a section which is
         valid only for testing, and linking with these symbols will break
         in library updates.
       - Symbols mentioned in installed headers go in the exported sections
         and are considered part of the ABI.
       - All internal symbols move to internal headers.
       - The _nettle_md5_compress and _nettle_sha1_compress become exported
         without the _nettle prefix, due to existing usage.
    xts.c 5.43 KiB
    /* xts.c
    
       XEX-based tweaked-codebook mode with ciphertext stealing (XTS)
    
       Copyright (C) 2018 Red Hat, Inc.
    
       This file is part of GNU Nettle.
    
       GNU Nettle is free software: you can redistribute it and/or
       modify it under the terms of either:
    
         * the GNU Lesser General Public License as published by the Free
           Software Foundation; either version 3 of the License, or (at your
           option) any later version.
    
       or
    
         * the GNU General Public License as published by the Free
           Software Foundation; either version 2 of the License, or (at your
           option) any later version.
    
       or both in parallel, as here.
    
       GNU Nettle is distributed in the hope that it will be useful,
       but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
       General Public License for more details.
    
       You should have received copies of the GNU General Public License and
       the GNU Lesser General Public License along with this program.  If
       not, see http://www.gnu.org/licenses/.
    */
    
    #if HAVE_CONFIG_H
    # include "config.h"
    #endif
    
    #include <assert.h>
    #include <stdlib.h>
    #include <string.h>
    
    #include "xts.h"
    
    #include "macros.h"
    #include "memxor.h"
    #include "nettle-internal.h"
    #include "block-internal.h"
    
    static void
    check_length(size_t length, uint8_t *dst)
    {
      assert(length >= XTS_BLOCK_SIZE);
      /* asserts may be compiled out, try to save the user by zeroing the dst in
       * case the buffer contains sensitive data (like the clear text for inplace
       * encryption) */
      if (length < XTS_BLOCK_SIZE)
        memset(dst, '\0', length);
    }
    
    /* works also for inplace encryption/decryption */
    
    void
    xts_encrypt_message(const void *enc_ctx, const void *twk_ctx,
    	            nettle_cipher_func *encf,
    	            const uint8_t *tweak, size_t length,
    	            uint8_t *dst, const uint8_t *src)
    {
      union nettle_block16 T;
      union nettle_block16 P;
    
      check_length(length, dst);
    
      encf(twk_ctx, XTS_BLOCK_SIZE, T.b, tweak);
    
      /* the zeroth power of alpha is the initial ciphertext value itself, so we
       * skip shifting and do it at the end of each block operation instead */
      for (;length >= 2 * XTS_BLOCK_SIZE || length == XTS_BLOCK_SIZE;
           length -= XTS_BLOCK_SIZE, src += XTS_BLOCK_SIZE, dst += XTS_BLOCK_SIZE)
        {
          memxor3(P.b, src, T.b, XTS_BLOCK_SIZE);	/* P -> PP */
          encf(enc_ctx, XTS_BLOCK_SIZE, dst, P.b);  /* CC */
          memxor(dst, T.b, XTS_BLOCK_SIZE);	        /* CC -> C */
    
          /* shift T for next block if any */
          if (length > XTS_BLOCK_SIZE)
              block16_mulx_le(&T, &T);
        }
    
      /* if the last block is partial, handle via stealing */
      if (length)
        {
          /* S Holds the real C(n-1) (Whole last block to steal from) */
          union nettle_block16 S;
    
          memxor3(P.b, src, T.b, XTS_BLOCK_SIZE);	/* P -> PP */
          encf(enc_ctx, XTS_BLOCK_SIZE, S.b, P.b);  /* CC */
          memxor(S.b, T.b, XTS_BLOCK_SIZE);	        /* CC -> S */
    
          /* shift T for next block */
          block16_mulx_le(&T, &T);
    
          length -= XTS_BLOCK_SIZE;
          src += XTS_BLOCK_SIZE;
    
          memxor3(P.b, src, T.b, length);           /* P |.. */
          /* steal ciphertext to complete block */
          memxor3(P.b + length, S.b + length, T.b + length,
                  XTS_BLOCK_SIZE - length);         /* ..| S_2 -> PP */
    
          encf(enc_ctx, XTS_BLOCK_SIZE, dst, P.b);  /* CC */
          memxor(dst, T.b, XTS_BLOCK_SIZE);         /* CC -> C(n-1) */
    
          /* Do this after we read src so inplace operations do not break */
          dst += XTS_BLOCK_SIZE;
          memcpy(dst, S.b, length);                 /* S_1 -> C(n) */
        }
    }
    
    void
    xts_decrypt_message(const void *dec_ctx, const void *twk_ctx,
    	            nettle_cipher_func *decf, nettle_cipher_func *encf,
    	            const uint8_t *tweak, size_t length,
    	            uint8_t *dst, const uint8_t *src)
    {
      union nettle_block16 T;
      union nettle_block16 C;
    
      check_length(length, dst);
    
      encf(twk_ctx, XTS_BLOCK_SIZE, T.b, tweak);
    
      for (;length >= 2 * XTS_BLOCK_SIZE || length == XTS_BLOCK_SIZE;
           length -= XTS_BLOCK_SIZE, src += XTS_BLOCK_SIZE, dst += XTS_BLOCK_SIZE)
        {
          memxor3(C.b, src, T.b, XTS_BLOCK_SIZE);	/* c -> CC */
          decf(dec_ctx, XTS_BLOCK_SIZE, dst, C.b);  /* PP */
          memxor(dst, T.b, XTS_BLOCK_SIZE);	        /* PP -> P */
    
          /* shift T for next block if any */
          if (length > XTS_BLOCK_SIZE)
              block16_mulx_le(&T, &T);
        }
    
      /* if the last block is partial, handle via stealing */
      if (length)
        {
          union nettle_block16 T1;
          /* S Holds the real P(n) (with part of stolen ciphertext) */
          union nettle_block16 S;
    
          /* we need the last T(n) and save the T(n-1) for later */
          block16_mulx_le(&T1, &T);
    
          memxor3(C.b, src, T1.b, XTS_BLOCK_SIZE);	/* C -> CC */
          decf(dec_ctx, XTS_BLOCK_SIZE, S.b, C.b);  /* PP */
          memxor(S.b, T1.b, XTS_BLOCK_SIZE);	/* PP -> S */
    
          /* process next block (Pn-1) */
          length -= XTS_BLOCK_SIZE;
          src += XTS_BLOCK_SIZE;
    
          /* Prepare C, P holds the real P(n) */
          memxor3(C.b, src, T.b, length);	        /* C_1 |.. */
          memxor3(C.b + length, S.b + length, T.b + length,
                  XTS_BLOCK_SIZE - length);         /* ..| S_2 -> CC */
          decf(dec_ctx, XTS_BLOCK_SIZE, dst, C.b);  /* PP */
          memxor(dst, T.b, XTS_BLOCK_SIZE);	        /* PP -> P(n-1) */
    
          /* Do this after we read src so inplace operations do not break */
          dst += XTS_BLOCK_SIZE;
          memcpy(dst, S.b, length);                 /* S_1 -> P(n) */
        }
    }