diff options
Diffstat (limited to 'package/utils/px5g/src/library/rsa.c')
-rw-r--r-- | package/utils/px5g/src/library/rsa.c | 750 |
1 files changed, 0 insertions, 750 deletions
diff --git a/package/utils/px5g/src/library/rsa.c b/package/utils/px5g/src/library/rsa.c deleted file mode 100644 index 131b6c6..0000000 --- a/package/utils/px5g/src/library/rsa.c +++ /dev/null @@ -1,750 +0,0 @@ -/* - * The RSA public-key cryptosystem - * - * Based on XySSL: Copyright (C) 2006-2008 Christophe Devine - * - * Copyright (C) 2009 Paul Bakker <polarssl_maintainer at polarssl dot org> - * - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * * Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * * Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * * Neither the names of PolarSSL or XySSL nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS - * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED - * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ -/* - * RSA was designed by Ron Rivest, Adi Shamir and Len Adleman. - * - * http://theory.lcs.mit.edu/~rivest/rsapaper.pdf - * http://www.cacr.math.uwaterloo.ca/hac/about/chap8.pdf - */ - -#include "polarssl/config.h" - -#if defined(POLARSSL_RSA_C) - -#include "polarssl/rsa.h" - -#include <stdlib.h> -#include <string.h> -#include <stdio.h> - -/* - * Initialize an RSA context - */ -void rsa_init( rsa_context *ctx, - int padding, - int hash_id, - int (*f_rng)(void *), - void *p_rng ) -{ - memset( ctx, 0, sizeof( rsa_context ) ); - - ctx->padding = padding; - ctx->hash_id = hash_id; - - ctx->f_rng = f_rng; - ctx->p_rng = p_rng; -} - -#if defined(POLARSSL_GENPRIME) - -/* - * Generate an RSA keypair - */ -int rsa_gen_key( rsa_context *ctx, int nbits, int exponent ) -{ - int ret; - mpi P1, Q1, H, G; - - if( ctx->f_rng == NULL || nbits < 128 || exponent < 3 ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - - mpi_init( &P1, &Q1, &H, &G, NULL ); - - /* - * find primes P and Q with Q < P so that: - * GCD( E, (P-1)*(Q-1) ) == 1 - */ - MPI_CHK( mpi_lset( &ctx->E, exponent ) ); - - do - { - MPI_CHK( mpi_gen_prime( &ctx->P, ( nbits + 1 ) >> 1, 0, - ctx->f_rng, ctx->p_rng ) ); - - MPI_CHK( mpi_gen_prime( &ctx->Q, ( nbits + 1 ) >> 1, 0, - ctx->f_rng, ctx->p_rng ) ); - - if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 ) - mpi_swap( &ctx->P, &ctx->Q ); - - if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 ) - continue; - - MPI_CHK( mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) ); - if( mpi_msb( &ctx->N ) != nbits ) - continue; - - MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) ); - MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) ); - MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) ); - MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) ); - } - while( mpi_cmp_int( &G, 1 ) != 0 ); - - /* - * D = E^-1 mod ((P-1)*(Q-1)) - * DP = D mod (P - 1) - * DQ = D mod (Q - 1) - * QP = Q^-1 mod P - */ - MPI_CHK( mpi_inv_mod( &ctx->D , &ctx->E, &H ) ); - MPI_CHK( mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) ); - MPI_CHK( mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) ); - MPI_CHK( mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) ); - - ctx->len = ( mpi_msb( &ctx->N ) + 7 ) >> 3; - -cleanup: - - mpi_free( &G, &H, &Q1, &P1, NULL ); - - if( ret != 0 ) - { - rsa_free( ctx ); - return( POLARSSL_ERR_RSA_KEY_GEN_FAILED | ret ); - } - - return( 0 ); -} - -#endif - -/* - * Check a public RSA key - */ -int rsa_check_pubkey( rsa_context *ctx ) -{ - if( ( ctx->N.p[0] & 1 ) == 0 || - ( ctx->E.p[0] & 1 ) == 0 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); - - if( mpi_msb( &ctx->N ) < 128 || - mpi_msb( &ctx->N ) > 4096 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); - - if( mpi_msb( &ctx->E ) < 2 || - mpi_msb( &ctx->E ) > 64 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); - - return( 0 ); -} - -/* - * Check a private RSA key - */ -int rsa_check_privkey( rsa_context *ctx ) -{ - int ret; - mpi PQ, DE, P1, Q1, H, I, G; - - if( ( ret = rsa_check_pubkey( ctx ) ) != 0 ) - return( ret ); - - mpi_init( &PQ, &DE, &P1, &Q1, &H, &I, &G, NULL ); - - MPI_CHK( mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) ); - MPI_CHK( mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) ); - MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) ); - MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) ); - MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) ); - MPI_CHK( mpi_mod_mpi( &I, &DE, &H ) ); - MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) ); - - if( mpi_cmp_mpi( &PQ, &ctx->N ) == 0 && - mpi_cmp_int( &I, 1 ) == 0 && - mpi_cmp_int( &G, 1 ) == 0 ) - { - mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, NULL ); - return( 0 ); - } - -cleanup: - - mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, NULL ); - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED | ret ); -} - -/* - * Do an RSA public key operation - */ -int rsa_public( rsa_context *ctx, - unsigned char *input, - unsigned char *output ) -{ - int ret, olen; - mpi T; - - mpi_init( &T, NULL ); - - MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); - - if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) - { - mpi_free( &T, NULL ); - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - - olen = ctx->len; - MPI_CHK( mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) ); - MPI_CHK( mpi_write_binary( &T, output, olen ) ); - -cleanup: - - mpi_free( &T, NULL ); - - if( ret != 0 ) - return( POLARSSL_ERR_RSA_PUBLIC_FAILED | ret ); - - return( 0 ); -} - -/* - * Do an RSA private key operation - */ -int rsa_private( rsa_context *ctx, - unsigned char *input, - unsigned char *output ) -{ - int ret, olen; - mpi T, T1, T2; - - mpi_init( &T, &T1, &T2, NULL ); - - MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); - - if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) - { - mpi_free( &T, NULL ); - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - -#if 0 - MPI_CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) ); -#else - /* - * faster decryption using the CRT - * - * T1 = input ^ dP mod P - * T2 = input ^ dQ mod Q - */ - MPI_CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) ); - MPI_CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) ); - - /* - * T = (T1 - T2) * (Q^-1 mod P) mod P - */ - MPI_CHK( mpi_sub_mpi( &T, &T1, &T2 ) ); - MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) ); - MPI_CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) ); - - /* - * output = T2 + T * Q - */ - MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) ); - MPI_CHK( mpi_add_mpi( &T, &T2, &T1 ) ); -#endif - - olen = ctx->len; - MPI_CHK( mpi_write_binary( &T, output, olen ) ); - -cleanup: - - mpi_free( &T, &T1, &T2, NULL ); - - if( ret != 0 ) - return( POLARSSL_ERR_RSA_PRIVATE_FAILED | ret ); - - return( 0 ); -} - -/* - * Add the message padding, then do an RSA operation - */ -int rsa_pkcs1_encrypt( rsa_context *ctx, - int mode, int ilen, - unsigned char *input, - unsigned char *output ) -{ - int nb_pad, olen; - unsigned char *p = output; - - olen = ctx->len; - - switch( ctx->padding ) - { - case RSA_PKCS_V15: - - if( ilen < 0 || olen < ilen + 11 ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - - nb_pad = olen - 3 - ilen; - - *p++ = 0; - *p++ = RSA_CRYPT; - - while( nb_pad-- > 0 ) - { - do { - *p = (unsigned char) rand(); - } while( *p == 0 ); - p++; - } - *p++ = 0; - memcpy( p, input, ilen ); - break; - - default: - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - - return( ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, output, output ) - : rsa_private( ctx, output, output ) ); -} - -/* - * Do an RSA operation, then remove the message padding - */ -int rsa_pkcs1_decrypt( rsa_context *ctx, - int mode, int *olen, - unsigned char *input, - unsigned char *output, - int output_max_len) -{ - int ret, ilen; - unsigned char *p; - unsigned char buf[512]; - - ilen = ctx->len; - - if( ilen < 16 || ilen > (int) sizeof( buf ) ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - - ret = ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, input, buf ) - : rsa_private( ctx, input, buf ); - - if( ret != 0 ) - return( ret ); - - p = buf; - - switch( ctx->padding ) - { - case RSA_PKCS_V15: - - if( *p++ != 0 || *p++ != RSA_CRYPT ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - - while( *p != 0 ) - { - if( p >= buf + ilen - 1 ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - p++; - } - p++; - break; - - default: - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - - if (ilen - (int)(p - buf) > output_max_len) - return( POLARSSL_ERR_RSA_OUTPUT_TO_LARGE ); - - *olen = ilen - (int)(p - buf); - memcpy( output, p, *olen ); - - return( 0 ); -} - -/* - * Do an RSA operation to sign the message digest - */ -int rsa_pkcs1_sign( rsa_context *ctx, - int mode, - int hash_id, - int hashlen, - unsigned char *hash, - unsigned char *sig ) -{ - int nb_pad, olen; - unsigned char *p = sig; - - olen = ctx->len; - - switch( ctx->padding ) - { - case RSA_PKCS_V15: - - switch( hash_id ) - { - case RSA_RAW: - nb_pad = olen - 3 - hashlen; - break; - - case RSA_MD2: - case RSA_MD4: - case RSA_MD5: - nb_pad = olen - 3 - 34; - break; - - case RSA_SHA1: - nb_pad = olen - 3 - 35; - break; - - default: - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - - if( nb_pad < 8 ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - - *p++ = 0; - *p++ = RSA_SIGN; - memset( p, 0xFF, nb_pad ); - p += nb_pad; - *p++ = 0; - break; - - default: - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - - switch( hash_id ) - { - case RSA_RAW: - memcpy( p, hash, hashlen ); - break; - - case RSA_MD2: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 2; break; - - case RSA_MD4: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 4; break; - - case RSA_MD5: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 5; break; - - case RSA_SHA1: - memcpy( p, ASN1_HASH_SHA1, 15 ); - memcpy( p + 15, hash, 20 ); - break; - - default: - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - - return( ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, sig, sig ) - : rsa_private( ctx, sig, sig ) ); -} - -/* - * Do an RSA operation and check the message digest - */ -int rsa_pkcs1_verify( rsa_context *ctx, - int mode, - int hash_id, - int hashlen, - unsigned char *hash, - unsigned char *sig ) -{ - int ret, len, siglen; - unsigned char *p, c; - unsigned char buf[512]; - - siglen = ctx->len; - - if( siglen < 16 || siglen > (int) sizeof( buf ) ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - - ret = ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, sig, buf ) - : rsa_private( ctx, sig, buf ); - - if( ret != 0 ) - return( ret ); - - p = buf; - - switch( ctx->padding ) - { - case RSA_PKCS_V15: - - if( *p++ != 0 || *p++ != RSA_SIGN ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - - while( *p != 0 ) - { - if( p >= buf + siglen - 1 || *p != 0xFF ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - p++; - } - p++; - break; - - default: - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - - len = siglen - (int)( p - buf ); - - if( len == 34 ) - { - c = p[13]; - p[13] = 0; - - if( memcmp( p, ASN1_HASH_MDX, 18 ) != 0 ) - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - - if( ( c == 2 && hash_id == RSA_MD2 ) || - ( c == 4 && hash_id == RSA_MD4 ) || - ( c == 5 && hash_id == RSA_MD5 ) ) - { - if( memcmp( p + 18, hash, 16 ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - } - - if( len == 35 && hash_id == RSA_SHA1 ) - { - if( memcmp( p, ASN1_HASH_SHA1, 15 ) == 0 && - memcmp( p + 15, hash, 20 ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - - if( len == hashlen && hash_id == RSA_RAW ) - { - if( memcmp( p, hash, hashlen ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); -} - -/* - * Free the components of an RSA key - */ -void rsa_free( rsa_context *ctx ) -{ - mpi_free( &ctx->RQ, &ctx->RP, &ctx->RN, - &ctx->QP, &ctx->DQ, &ctx->DP, - &ctx->Q, &ctx->P, &ctx->D, - &ctx->E, &ctx->N, NULL ); -} - -#if defined(POLARSSL_SELF_TEST) - -#include "polarssl/sha1.h" - -/* - * Example RSA-1024 keypair, for test purposes - */ -#define KEY_LEN 128 - -#define RSA_N "9292758453063D803DD603D5E777D788" \ - "8ED1D5BF35786190FA2F23EBC0848AEA" \ - "DDA92CA6C3D80B32C4D109BE0F36D6AE" \ - "7130B9CED7ACDF54CFC7555AC14EEBAB" \ - "93A89813FBF3C4F8066D2D800F7C38A8" \ - "1AE31942917403FF4946B0A83D3D3E05" \ - "EE57C6F5F5606FB5D4BC6CD34EE0801A" \ - "5E94BB77B07507233A0BC7BAC8F90F79" - -#define RSA_E "10001" - -#define RSA_D "24BF6185468786FDD303083D25E64EFC" \ - "66CA472BC44D253102F8B4A9D3BFA750" \ - "91386C0077937FE33FA3252D28855837" \ - "AE1B484A8A9A45F7EE8C0C634F99E8CD" \ - "DF79C5CE07EE72C7F123142198164234" \ - "CABB724CF78B8173B9F880FC86322407" \ - "AF1FEDFDDE2BEB674CA15F3E81A1521E" \ - "071513A1E85B5DFA031F21ECAE91A34D" - -#define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \ - "2C01CAD19EA484A87EA4377637E75500" \ - "FCB2005C5C7DD6EC4AC023CDA285D796" \ - "C3D9E75E1EFC42488BB4F1D13AC30A57" - -#define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \ - "E211C2B9E5DB1ED0BF61D0D9899620F4" \ - "910E4168387E3C30AA1E00C339A79508" \ - "8452DD96A9A5EA5D9DCA68DA636032AF" - -#define RSA_DP "C1ACF567564274FB07A0BBAD5D26E298" \ - "3C94D22288ACD763FD8E5600ED4A702D" \ - "F84198A5F06C2E72236AE490C93F07F8" \ - "3CC559CD27BC2D1CA488811730BB5725" - -#define RSA_DQ "4959CBF6F8FEF750AEE6977C155579C7" \ - "D8AAEA56749EA28623272E4F7D0592AF" \ - "7C1F1313CAC9471B5C523BFE592F517B" \ - "407A1BD76C164B93DA2D32A383E58357" - -#define RSA_QP "9AE7FBC99546432DF71896FC239EADAE" \ - "F38D18D2B2F0E2DD275AA977E2BF4411" \ - "F5A3B2A5D33605AEBBCCBA7FEB9F2D2F" \ - "A74206CEC169D74BF5A8C50D6F48EA08" - -#define PT_LEN 24 -#define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \ - "\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD" - -/* - * Checkup routine - */ -int rsa_self_test( int verbose ) -{ - int len; - rsa_context rsa; - unsigned char sha1sum[20]; - unsigned char rsa_plaintext[PT_LEN]; - unsigned char rsa_decrypted[PT_LEN]; - unsigned char rsa_ciphertext[KEY_LEN]; - - memset( &rsa, 0, sizeof( rsa_context ) ); - - rsa.len = KEY_LEN; - mpi_read_string( &rsa.N , 16, RSA_N ); - mpi_read_string( &rsa.E , 16, RSA_E ); - mpi_read_string( &rsa.D , 16, RSA_D ); - mpi_read_string( &rsa.P , 16, RSA_P ); - mpi_read_string( &rsa.Q , 16, RSA_Q ); - mpi_read_string( &rsa.DP, 16, RSA_DP ); - mpi_read_string( &rsa.DQ, 16, RSA_DQ ); - mpi_read_string( &rsa.QP, 16, RSA_QP ); - - if( verbose != 0 ) - printf( " RSA key validation: " ); - - if( rsa_check_pubkey( &rsa ) != 0 || - rsa_check_privkey( &rsa ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - - return( 1 ); - } - - if( verbose != 0 ) - printf( "passed\n PKCS#1 encryption : " ); - - memcpy( rsa_plaintext, RSA_PT, PT_LEN ); - - if( rsa_pkcs1_encrypt( &rsa, RSA_PUBLIC, PT_LEN, - rsa_plaintext, rsa_ciphertext ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - - return( 1 ); - } - - if( verbose != 0 ) - printf( "passed\n PKCS#1 decryption : " ); - - if( rsa_pkcs1_decrypt( &rsa, RSA_PRIVATE, &len, - rsa_ciphertext, rsa_decrypted, - sizeof(rsa_decrypted) ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - - return( 1 ); - } - - if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - - return( 1 ); - } - - if( verbose != 0 ) - printf( "passed\n PKCS#1 data sign : " ); - - sha1( rsa_plaintext, PT_LEN, sha1sum ); - - if( rsa_pkcs1_sign( &rsa, RSA_PRIVATE, RSA_SHA1, 20, - sha1sum, rsa_ciphertext ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - - return( 1 ); - } - - if( verbose != 0 ) - printf( "passed\n PKCS#1 sig. verify: " ); - - if( rsa_pkcs1_verify( &rsa, RSA_PUBLIC, RSA_SHA1, 20, - sha1sum, rsa_ciphertext ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - - return( 1 ); - } - - if( verbose != 0 ) - printf( "passed\n\n" ); - - rsa_free( &rsa ); - - return( 0 ); -} - -#endif - -#endif |