See ChangeLog: Mon Sep 18 16:35:45 CEST 2000 Werner Koch

1 files changed, 116 insertions, 20 deletions

diff --git a/cipher/rsa.c b/cipher/rsa.c
index 5d852cd8..2bb45100 100644
--- a/cipher/rsa.c
+++ b/cipher/rsa.c
@@ -1,10 +1,6 @@
 /* rsa.c  -  RSA function
  *	Copyright (C) 1997, 1998, 1999 by Werner Koch (dd9jn)
  *	Copyright (C) 2000 Free Software Foundation, Inc.
- ***********************************************************************
- * ATTENTION: This code should not be used in the United States
- * before the U.S. Patent #4,405,829 expires on September 20, 2000!
- ***********************************************************************
  *
  * This file is part of GnuPG.
  *
@@ -23,11 +19,16 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 
+/* This code uses an algorithm protected by U.S. Patent #4,405,829
+   which expires on September 20, 2000.  The patent holder placed that
+   patent into the public domain on Sep 6th, 2000.
+*/
+
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include "util.h"
+#include "g10lib.h"
 #include "mpi.h"
 #include "cipher.h"
 #include "rsa.h"
@@ -68,7 +69,7 @@ test_keys( RSA_secret_key *sk, unsigned nbits )
     pk.e = sk->e;
     {	char *p = get_random_bits( nbits, 0, 0 );
 	mpi_set_buffer( test, p, (nbits+7)/8, 0 );
-	m_free(p);
+	g10_free(p);
     }
 
     public( out1, test, &pk );
@@ -200,22 +201,111 @@ public(MPI output, MPI input, RSA_public_key *pkey )
 	mpi_powm( output, input, pkey->e, pkey->n );
 }
 
+#if 0
+static void
+stronger_key_check ( RSA_secret_key *skey )
+{
+    MPI t = mpi_alloc_secure ( 0 );
+    MPI t1 = mpi_alloc_secure ( 0 );
+    MPI t2 = mpi_alloc_secure ( 0 );
+    MPI phi = mpi_alloc_secure ( 0 );
+
+    /* check that n == p * q */
+    mpi_mul( t, skey->p, skey->q);
+    if (mpi_cmp( t, skey->n) )
+        log_info ( "RSA Oops: n != p * q\n" );
+
+    /* check that p is less than q */
+    if( mpi_cmp( skey->p, skey->q ) > 0 )
+	log_info ("RSA Oops: p >= q\n");
+
+
+    /* check that e divides neither p-1 nor q-1 */
+    mpi_sub_ui(t, skey->p, 1 );
+    mpi_fdiv_r(t, t, skey->e );
+    if ( !mpi_cmp_ui( t, 0) )
+        log_info ( "RSA Oops: e divides p-1\n" );
+    mpi_sub_ui(t, skey->q, 1 );
+    mpi_fdiv_r(t, t, skey->e );
+    if ( !mpi_cmp_ui( t, 0) )
+        log_info ( "RSA Oops: e divides q-1\n" );
+
+    /* check that d is correct */
+    mpi_sub_ui( t1, skey->p, 1 );
+    mpi_sub_ui( t2, skey->q, 1 );
+    mpi_mul( phi, t1, t2 );
+    mpi_gcd(t, t1, t2);
+    mpi_fdiv_q(t, phi, t);
+    mpi_invm(t, skey->e, t );
+    if ( mpi_cmp(t, skey->d ) )
+        log_info ( "RSA Oops: d is wrong\n");
+
+    /* check for crrectness of u */
+    mpi_invm(t, skey->p, skey->q );
+    if ( mpi_cmp(t, skey->u ) )
+        log_info ( "RSA Oops: u is wrong\n");
+   
+    log_info ( "RSA secret key check finished\n");
+
+    mpi_free (t);
+    mpi_free (t1);
+    mpi_free (t2);
+    mpi_free (phi);
+}
+#endif
+
+
+
 /****************
  * Secret key operation. Encrypt INPUT with SKEY and put result into OUTPUT.
  *
  *	m = c^d mod n
  *
- * Where m is OUTPUT, c is INPUT and d,n are elements of PKEY.
+ * Or faster:
  *
- * FIXME: We should better use the Chinese Remainder Theorem
+ *      m1 = c ^ (d mod (p-1)) mod p 
+ *      m2 = c ^ (d mod (q-1)) mod q 
+ *      h = u * (m2 - m1) mod q 
+ *      m = m1 + h * p
+ *
+ * Where m is OUTPUT, c is INPUT and d,n,p,q,u are elements of SKEY.
  */
 static void
 secret(MPI output, MPI input, RSA_secret_key *skey )
 {
+  #if 0
     mpi_powm( output, input, skey->d, skey->n );
+  #else
+    MPI m1   = mpi_alloc_secure( mpi_get_nlimbs(skey->n)+1 );
+    MPI m2   = mpi_alloc_secure( mpi_get_nlimbs(skey->n)+1 );
+    MPI h    = mpi_alloc_secure( mpi_get_nlimbs(skey->n)+1 );
+
+    /* m1 = c ^ (d mod (p-1)) mod p */
+    mpi_sub_ui( h, skey->p, 1  );
+    mpi_fdiv_r( h, skey->d, h );   
+    mpi_powm( m1, input, h, skey->p );
+    /* m2 = c ^ (d mod (q-1)) mod q */
+    mpi_sub_ui( h, skey->q, 1  );
+    mpi_fdiv_r( h, skey->d, h );
+    mpi_powm( m2, input, h, skey->q );
+    /* h = u * ( m2 - m1 ) mod q */
+    mpi_sub( h, m2, m1 );
+    if ( mpi_is_neg( h ) ) 
+        mpi_add ( h, h, skey->q );
+    mpi_mulm( h, skey->u, h, skey->q ); 
+    /* m = m2 + h * p */
+    mpi_mul ( h, h, skey->p );
+    mpi_add ( output, m1, h );
+    /* ready */
+    
+    mpi_free ( h );
+    mpi_free ( m1 );
+    mpi_free ( m2 );
+  #endif
 }
 
 
+
 /*********************************************
  **************  interface  ******************
  *********************************************/
@@ -226,7 +316,7 @@ rsa_generate( int algo, unsigned nbits, MPI *skey, MPI **retfactors )
     RSA_secret_key sk;
 
     if( !is_RSA(algo) )
-	return G10ERR_PUBKEY_ALGO;
+	return GCRYERR_INV_PK_ALGO;
 
     generate( &sk, nbits );
     skey[0] = sk.n;
@@ -236,7 +326,7 @@ rsa_generate( int algo, unsigned nbits, MPI *skey, MPI **retfactors )
     skey[4] = sk.q;
     skey[5] = sk.u;
     /* make an empty list of factors */
-    *retfactors = m_alloc_clear( 1 * sizeof **retfactors );
+    *retfactors = g10_xcalloc( 1, sizeof **retfactors );
     return 0;
 }
 
@@ -247,7 +337,7 @@ rsa_check_secret_key( int algo, MPI *skey )
     RSA_secret_key sk;
 
     if( !is_RSA(algo) )
-	return G10ERR_PUBKEY_ALGO;
+	return GCRYERR_INV_PK_ALGO;
 
     sk.n = skey[0];
     sk.e = skey[1];
@@ -256,7 +346,7 @@ rsa_check_secret_key( int algo, MPI *skey )
     sk.q = skey[4];
     sk.u = skey[5];
     if( !check_secret_key( &sk ) )
-	return G10ERR_BAD_SECKEY;
+	return GCRYERR_INV_PK_ALGO;
 
     return 0;
 }
@@ -269,7 +359,7 @@ rsa_encrypt( int algo, MPI *resarr, MPI data, MPI *pkey )
     RSA_public_key pk;
 
     if( algo != 1 && algo != 2 )
-	return G10ERR_PUBKEY_ALGO;
+	return GCRYERR_INV_PK_ALGO;
 
     pk.n = pkey[0];
     pk.e = pkey[1];
@@ -284,7 +374,7 @@ rsa_decrypt( int algo, MPI *result, MPI *data, MPI *skey )
     RSA_secret_key sk;
 
     if( algo != 1 && algo != 2 )
-	return G10ERR_PUBKEY_ALGO;
+	return GCRYERR_INV_PK_ALGO;
 
     sk.n = skey[0];
     sk.e = skey[1];
@@ -303,7 +393,7 @@ rsa_sign( int algo, MPI *resarr, MPI data, MPI *skey )
     RSA_secret_key sk;
 
     if( algo != 1 && algo != 3 )
-	return G10ERR_PUBKEY_ALGO;
+	return GCRYERR_INV_PK_ALGO;
 
     sk.n = skey[0];
     sk.e = skey[1];
@@ -326,13 +416,13 @@ rsa_verify( int algo, MPI hash, MPI *data, MPI *pkey,
     int rc;
 
     if( algo != 1 && algo != 3 )
-	return G10ERR_PUBKEY_ALGO;
+	return GCRYERR_INV_PK_ALGO;
     pk.n = pkey[0];
     pk.e = pkey[1];
     result = mpi_alloc( (160+BITS_PER_MPI_LIMB-1)/BITS_PER_MPI_LIMB);
     public( result, data[0], &pk );
     /*rc = (*cmp)( opaquev, result );*/
-    rc = mpi_cmp( result, hash )? G10ERR_BAD_SIGN:0;
+    rc = mpi_cmp( result, hash )? GCRYERR_BAD_SIGNATURE:0;
     mpi_free(result);
 
     return rc;
@@ -366,10 +456,16 @@ rsa_get_info( int algo,
     *nsig = 1;
 
     switch( algo ) {
-      case 1: *usage = PUBKEY_USAGE_SIG | PUBKEY_USAGE_ENC; return "RSA";
-      case 2: *usage = PUBKEY_USAGE_ENC; return "RSA-E";
-      case 3: *usage = PUBKEY_USAGE_SIG; return "RSA-S";
+      case 1: *usage = GCRY_PK_USAGE_SIGN | GCRY_PK_USAGE_ENCR; return "RSA";
+      case 2: *usage = GCRY_PK_USAGE_ENCR; return "RSA-E";
+      case 3: *usage = GCRY_PK_USAGE_SIGN; return "RSA-S";
       default:*usage = 0; return NULL;
     }
 }
 
+
+
+
+
+
+