/contrib/ntp/util/ntp-keygen.c
C | 1890 lines | 1176 code | 126 blank | 588 comment | 215 complexity | 7a218ffa5338ddea4df3371c6fe5f07b MD5 | raw file
Possible License(s): MPL-2.0-no-copyleft-exception, BSD-3-Clause, LGPL-2.0, LGPL-2.1, BSD-2-Clause, 0BSD, JSON, AGPL-1.0, GPL-2.0
- /*
- * Program to generate cryptographic keys for NTP clients and servers
- *
- * This program generates files "ntpkey_<type>_<hostname>.<filestamp>",
- * where <type> is the file type, <hostname> is the generating host and
- * <filestamp> is the NTP seconds in decimal format. The NTP programs
- * expect generic names such as "ntpkey_<type>_whimsy.udel.edu" with the
- * association maintained by soft links.
- *
- * Files are prefixed with a header giving the name and date of creation
- * followed by a type-specific descriptive label and PEM-encoded data
- * string compatible with programs of the OpenSSL library.
- *
- * Note that private keys can be password encrypted as per OpenSSL
- * conventions.
- *
- * The file types include
- *
- * ntpkey_MD5key_<hostname>.<filestamp>
- * MD5 (128-bit) keys used to compute message digests in symmetric
- * key cryptography
- *
- * ntpkey_RSAkey_<hostname>.<filestamp>
- * ntpkey_host_<hostname> (RSA) link
- * RSA private/public host key pair used for public key signatures
- * and data encryption
- *
- * ntpkey_DSAkey_<hostname>.<filestamp>
- * ntpkey_sign_<hostname> (RSA or DSA) link
- * DSA private/public sign key pair used for public key signatures,
- * but not data encryption
- *
- * ntpkey_IFFpar_<hostname>.<filestamp>
- * ntpkey_iff_<hostname> (IFF server/client) link
- * ntpkey_iffkey_<hostname> (IFF client) link
- * Schnorr (IFF) server/client identity parameters
- *
- * ntpkey_IFFkey_<hostname>.<filestamp>
- * Schnorr (IFF) client identity parameters
- *
- * ntpkey_GQpar_<hostname>.<filestamp>,
- * ntpkey_gq_<hostname> (GQ) link
- * Guillou-Quisquater (GQ) identity parameters
- *
- * ntpkey_MVpar_<hostname>.<filestamp>,
- * Mu-Varadharajan (MV) server identity parameters
- *
- * ntpkey_MVkeyX_<hostname>.<filestamp>,
- * ntpkey_mv_<hostname> (MV server) link
- * ntpkey_mvkey_<hostname> (MV client) link
- * Mu-Varadharajan (MV) client identity parameters
- *
- * ntpkey_XXXcert_<hostname>.<filestamp>
- * ntpkey_cert_<hostname> (RSA or DSA) link
- * X509v3 certificate using RSA or DSA public keys and signatures.
- * XXX is a code identifying the message digest and signature
- * encryption algorithm
- *
- * Available digest/signature schemes
- *
- * RSA: RSA-MD2, RSA-MD5, RSA-SHA, RSA-SHA1, RSA-MDC2, EVP-RIPEMD160
- * DSA: DSA-SHA, DSA-SHA1
- *
- * Note: Once in a while because of some statistical fluke this program
- * fails to generate and verify some cryptographic data, as indicated by
- * exit status -1. In this case simply run the program again. If the
- * program does complete with return code 0, the data are correct as
- * verified.
- *
- * These cryptographic routines are characterized by the prime modulus
- * size in bits. The default value of 512 bits is a compromise between
- * cryptographic strength and computing time and is ordinarily
- * considered adequate for this application. The routines have been
- * tested with sizes of 256, 512, 1024 and 2048 bits. Not all message
- * digest and signature encryption schemes work with sizes less than 512
- * bits. The computing time for sizes greater than 2048 bits is
- * prohibitive on all but the fastest processors. An UltraSPARC Blade
- * 1000 took something over nine minutes to generate and verify the
- * values with size 2048. An old SPARC IPC would take a week.
- *
- * The OpenSSL library used by this program expects a random seed file.
- * As described in the OpenSSL documentation, the file name defaults to
- * first the RANDFILE environment variable in the user's home directory
- * and then .rnd in the user's home directory.
- */
- #ifdef HAVE_CONFIG_H
- # include <config.h>
- #endif
- #include <string.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <unistd.h>
- #include <sys/stat.h>
- #include <sys/time.h>
- #if HAVE_SYS_TYPES_H
- # include <sys/types.h>
- #endif
- #include "ntp_types.h"
- #include "ntp_random.h"
- #include "l_stdlib.h"
- #include "ntp-keygen-opts.h"
- #ifdef SYS_WINNT
- extern int ntp_getopt P((int, char **, const char *));
- #define getopt ntp_getopt
- #define optarg ntp_optarg
- #endif
- #ifdef OPENSSL
- #include "openssl/bn.h"
- #include "openssl/evp.h"
- #include "openssl/err.h"
- #include "openssl/rand.h"
- #include "openssl/pem.h"
- #include "openssl/x509v3.h"
- #include <openssl/objects.h>
- #endif /* OPENSSL */
- /*
- * Cryptodefines
- */
- #define MD5KEYS 16 /* number of MD5 keys generated */
- #define JAN_1970 ULONG_CONST(2208988800) /* NTP seconds */
- #define YEAR ((long)60*60*24*365) /* one year in seconds */
- #define MAXFILENAME 256 /* max file name length */
- #define MAXHOSTNAME 256 /* max host name length */
- #ifdef OPENSSL
- #define PLEN 512 /* default prime modulus size (bits) */
- /*
- * Strings used in X509v3 extension fields
- */
- #define KEY_USAGE "digitalSignature,keyCertSign"
- #define BASIC_CONSTRAINTS "critical,CA:TRUE"
- #define EXT_KEY_PRIVATE "private"
- #define EXT_KEY_TRUST "trustRoot"
- #endif /* OPENSSL */
- /*
- * Prototypes
- */
- FILE *fheader P((const char *, const char *));
- void fslink P((const char *, const char *));
- int gen_md5 P((char *));
- #ifdef OPENSSL
- EVP_PKEY *gen_rsa P((char *));
- EVP_PKEY *gen_dsa P((char *));
- EVP_PKEY *gen_iff P((char *));
- EVP_PKEY *gen_gqpar P((char *));
- EVP_PKEY *gen_gqkey P((char *, EVP_PKEY *));
- EVP_PKEY *gen_mv P((char *));
- int x509 P((EVP_PKEY *, const EVP_MD *, char *, char *));
- void cb P((int, int, void *));
- EVP_PKEY *genkey P((char *, char *));
- u_long asn2ntp P((ASN1_TIME *));
- #endif /* OPENSSL */
- /*
- * Program variables
- */
- extern char *optarg; /* command line argument */
- int debug = 0; /* debug, not de bug */
- int rval; /* return status */
- #ifdef OPENSSL
- u_int modulus = PLEN; /* prime modulus size (bits) */
- #endif
- int nkeys = 0; /* MV keys */
- time_t epoch; /* Unix epoch (seconds) since 1970 */
- char *hostname; /* host name (subject name) */
- char *trustname; /* trusted host name (issuer name) */
- char filename[MAXFILENAME + 1]; /* file name */
- char *passwd1 = NULL; /* input private key password */
- char *passwd2 = NULL; /* output private key password */
- #ifdef OPENSSL
- long d0, d1, d2, d3; /* callback counters */
- #endif /* OPENSSL */
- #ifdef SYS_WINNT
- BOOL init_randfile();
- /*
- * Don't try to follow symbolic links
- */
- int
- readlink(char * link, char * file, int len) {
- return (-1);
- }
- /*
- * Don't try to create a symbolic link for now.
- * Just move the file to the name you need.
- */
- int
- symlink(char *filename, char *linkname) {
- DeleteFile(linkname);
- MoveFile(filename, linkname);
- return 0;
- }
- void
- InitWin32Sockets() {
- WORD wVersionRequested;
- WSADATA wsaData;
- wVersionRequested = MAKEWORD(2,0);
- if (WSAStartup(wVersionRequested, &wsaData))
- {
- fprintf(stderr, "No useable winsock.dll");
- exit(1);
- }
- }
- #endif /* SYS_WINNT */
- /*
- * Main program
- */
- int
- main(
- int argc, /* command line options */
- char **argv
- )
- {
- struct timeval tv; /* initialization vector */
- int md5key = 0; /* generate MD5 keys */
- #ifdef OPENSSL
- X509 *cert = NULL; /* X509 certificate */
- EVP_PKEY *pkey_host = NULL; /* host key */
- EVP_PKEY *pkey_sign = NULL; /* sign key */
- EVP_PKEY *pkey_iff = NULL; /* IFF parameters */
- EVP_PKEY *pkey_gq = NULL; /* GQ parameters */
- EVP_PKEY *pkey_mv = NULL; /* MV parameters */
- int hostkey = 0; /* generate RSA keys */
- int iffkey = 0; /* generate IFF parameters */
- int gqpar = 0; /* generate GQ parameters */
- int gqkey = 0; /* update GQ keys */
- int mvpar = 0; /* generate MV parameters */
- int mvkey = 0; /* update MV keys */
- char *sign = NULL; /* sign key */
- EVP_PKEY *pkey = NULL; /* temp key */
- const EVP_MD *ectx; /* EVP digest */
- char pathbuf[MAXFILENAME + 1];
- const char *scheme = NULL; /* digest/signature scheme */
- char *exten = NULL; /* private extension */
- char *grpkey = NULL; /* identity extension */
- int nid; /* X509 digest/signature scheme */
- FILE *fstr = NULL; /* file handle */
- u_int temp;
- #define iffsw HAVE_OPT(ID_KEY)
- #endif /* OPENSSL */
- char hostbuf[MAXHOSTNAME + 1];
- #ifdef SYS_WINNT
- /* Initialize before OpenSSL checks */
- InitWin32Sockets();
- if(!init_randfile())
- fprintf(stderr, "Unable to initialize .rnd file\n");
- #endif
- #ifdef OPENSSL
- /*
- * OpenSSL version numbers: MNNFFPPS: major minor fix patch status
- * We match major, minor, fix and status (not patch)
- */
- if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L) {
- fprintf(stderr,
- "OpenSSL version mismatch. Built against %lx, you have %lx\n",
- OPENSSL_VERSION_NUMBER, SSLeay());
- return (-1);
- } else {
- fprintf(stderr,
- "Using OpenSSL version %lx\n", SSLeay());
- }
- #endif /* OPENSSL */
- /*
- * Process options, initialize host name and timestamp.
- */
- gethostname(hostbuf, MAXHOSTNAME);
- hostname = hostbuf;
- #ifdef OPENSSL
- trustname = hostbuf;
- passwd1 = hostbuf;
- #endif
- #ifndef SYS_WINNT
- gettimeofday(&tv, 0);
- #else
- gettimeofday(&tv);
- #endif
- epoch = tv.tv_sec;
- rval = 0;
- {
- int optct = optionProcess(&ntp_keygenOptions, argc, argv);
- argc -= optct;
- argv += optct;
- }
- #ifdef OPENSSL
- if (HAVE_OPT( CERTIFICATE ))
- scheme = OPT_ARG( CERTIFICATE );
- #endif
- debug = DESC(DEBUG_LEVEL).optOccCt;
- #ifdef OPENSSL
- if (HAVE_OPT( GQ_PARAMS ))
- gqpar++;
- if (HAVE_OPT( GQ_KEYS ))
- gqkey++;
- if (HAVE_OPT( HOST_KEY ))
- hostkey++;
- if (HAVE_OPT( IFFKEY ))
- iffkey++;
- if (HAVE_OPT( ISSUER_NAME ))
- trustname = OPT_ARG( ISSUER_NAME );
- #endif
- if (HAVE_OPT( MD5KEY ))
- md5key++;
- #ifdef OPENSSL
- if (HAVE_OPT( MODULUS ))
- modulus = OPT_VALUE_MODULUS;
- if (HAVE_OPT( PVT_CERT ))
- exten = EXT_KEY_PRIVATE;
- if (HAVE_OPT( PVT_PASSWD ))
- passwd2 = OPT_ARG( PVT_PASSWD );
- if (HAVE_OPT( GET_PVT_PASSWD ))
- passwd1 = OPT_ARG( GET_PVT_PASSWD );
- if (HAVE_OPT( SIGN_KEY ))
- sign = OPT_ARG( SIGN_KEY );
- if (HAVE_OPT( SUBJECT_NAME ))
- hostname = OPT_ARG( SUBJECT_NAME );
- if (HAVE_OPT( TRUSTED_CERT ))
- exten = EXT_KEY_TRUST;
- if (HAVE_OPT( MV_PARAMS )) {
- mvpar++;
- nkeys = OPT_VALUE_MV_PARAMS;
- }
- if (HAVE_OPT( MV_KEYS )) {
- mvkey++;
- nkeys = OPT_VALUE_MV_KEYS;
- }
- #endif
- if (passwd1 != NULL && passwd2 == NULL)
- passwd2 = passwd1;
- #ifdef OPENSSL
- /*
- * Seed random number generator and grow weeds.
- */
- ERR_load_crypto_strings();
- OpenSSL_add_all_algorithms();
- if (RAND_file_name(pathbuf, MAXFILENAME) == NULL) {
- fprintf(stderr, "RAND_file_name %s\n",
- ERR_error_string(ERR_get_error(), NULL));
- return (-1);
- }
- temp = RAND_load_file(pathbuf, -1);
- if (temp == 0) {
- fprintf(stderr,
- "RAND_load_file %s not found or empty\n", pathbuf);
- return (-1);
- }
- fprintf(stderr,
- "Random seed file %s %u bytes\n", pathbuf, temp);
- RAND_add(&epoch, sizeof(epoch), 4.0);
- #endif
- /*
- * Generate new parameters and keys as requested. These replace
- * any values already generated.
- */
- if (md5key)
- gen_md5("MD5");
- #ifdef OPENSSL
- if (hostkey)
- pkey_host = genkey("RSA", "host");
- if (sign != NULL)
- pkey_sign = genkey(sign, "sign");
- if (iffkey)
- pkey_iff = gen_iff("iff");
- if (gqpar)
- pkey_gq = gen_gqpar("gq");
- if (mvpar)
- pkey_mv = gen_mv("mv");
- /*
- * If there is no new host key, look for an existing one. If not
- * found, create it.
- */
- while (pkey_host == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
- sprintf(filename, "ntpkey_host_%s", hostname);
- if ((fstr = fopen(filename, "r")) != NULL) {
- pkey_host = PEM_read_PrivateKey(fstr, NULL,
- NULL, passwd1);
- fclose(fstr);
- readlink(filename, filename, sizeof(filename));
- if (pkey_host == NULL) {
- fprintf(stderr, "Host key\n%s\n",
- ERR_error_string(ERR_get_error(),
- NULL));
- rval = -1;
- } else {
- fprintf(stderr,
- "Using host key %s\n", filename);
- }
- break;
- } else if ((pkey_host = genkey("RSA", "host")) ==
- NULL) {
- rval = -1;
- break;
- }
- }
- /*
- * If there is no new sign key, look for an existing one. If not
- * found, use the host key instead.
- */
- pkey = pkey_sign;
- while (pkey_sign == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
- sprintf(filename, "ntpkey_sign_%s", hostname);
- if ((fstr = fopen(filename, "r")) != NULL) {
- pkey_sign = PEM_read_PrivateKey(fstr, NULL,
- NULL, passwd1);
- fclose(fstr);
- readlink(filename, filename, sizeof(filename));
- if (pkey_sign == NULL) {
- fprintf(stderr, "Sign key\n%s\n",
- ERR_error_string(ERR_get_error(),
- NULL));
- rval = -1;
- } else {
- fprintf(stderr, "Using sign key %s\n",
- filename);
- }
- break;
- } else {
- pkey = pkey_host;
- fprintf(stderr, "Using host key as sign key\n");
- break;
- }
- }
- /*
- * If there is no new IFF file, look for an existing one.
- */
- if (pkey_iff == NULL && rval == 0) {
- sprintf(filename, "ntpkey_iff_%s", hostname);
- if ((fstr = fopen(filename, "r")) != NULL) {
- pkey_iff = PEM_read_PrivateKey(fstr, NULL,
- NULL, passwd1);
- fclose(fstr);
- readlink(filename, filename, sizeof(filename));
- if (pkey_iff == NULL) {
- fprintf(stderr, "IFF parameters\n%s\n",
- ERR_error_string(ERR_get_error(),
- NULL));
- rval = -1;
- } else {
- fprintf(stderr,
- "Using IFF parameters %s\n",
- filename);
- }
- }
- }
- /*
- * If there is no new GQ file, look for an existing one.
- */
- if (pkey_gq == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
- sprintf(filename, "ntpkey_gq_%s", hostname);
- if ((fstr = fopen(filename, "r")) != NULL) {
- pkey_gq = PEM_read_PrivateKey(fstr, NULL, NULL,
- passwd1);
- fclose(fstr);
- readlink(filename, filename, sizeof(filename));
- if (pkey_gq == NULL) {
- fprintf(stderr, "GQ parameters\n%s\n",
- ERR_error_string(ERR_get_error(),
- NULL));
- rval = -1;
- } else {
- fprintf(stderr,
- "Using GQ parameters %s\n",
- filename);
- }
- }
- }
- /*
- * If there is a GQ parameter file, create GQ private/public
- * keys and extract the public key for the certificate.
- */
- if (pkey_gq != NULL && rval == 0) {
- gen_gqkey("gq", pkey_gq);
- grpkey = BN_bn2hex(pkey_gq->pkey.rsa->q);
- }
- /*
- * Generate a X509v3 certificate.
- */
- while (scheme == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
- sprintf(filename, "ntpkey_cert_%s", hostname);
- if ((fstr = fopen(filename, "r")) != NULL) {
- cert = PEM_read_X509(fstr, NULL, NULL, NULL);
- fclose(fstr);
- readlink(filename, filename, sizeof(filename));
- if (cert == NULL) {
- fprintf(stderr, "Cert \n%s\n",
- ERR_error_string(ERR_get_error(),
- NULL));
- rval = -1;
- } else {
- nid = OBJ_obj2nid(
- cert->cert_info->signature->algorithm);
- scheme = OBJ_nid2sn(nid);
- fprintf(stderr,
- "Using scheme %s from %s\n", scheme,
- filename);
- break;
- }
- }
- scheme = "RSA-MD5";
- }
- if (pkey != NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
- ectx = EVP_get_digestbyname(scheme);
- if (ectx == NULL) {
- fprintf(stderr,
- "Invalid digest/signature combination %s\n",
- scheme);
- rval = -1;
- } else {
- x509(pkey, ectx, grpkey, exten);
- }
- }
- /*
- * Write the IFF client parameters and keys as a DSA private key
- * encoded in PEM. Note the private key is obscured.
- */
- if (pkey_iff != NULL && rval == 0 && HAVE_OPT(ID_KEY)) {
- DSA *dsa;
- char *sptr;
- char *tld;
- sptr = strrchr(filename, '.');
- tld = malloc(strlen(sptr)); /* we have an extra byte ... */
- strcpy(tld, 1+sptr); /* ... see? */
- sprintf(filename, "ntpkey_IFFkey_%s.%s", trustname,
- tld);
- free(tld);
- fprintf(stderr, "Writing new IFF key %s\n", filename);
- fprintf(stdout, "# %s\n# %s", filename, ctime(&epoch));
- dsa = pkey_iff->pkey.dsa;
- BN_copy(dsa->priv_key, BN_value_one());
- pkey = EVP_PKEY_new();
- EVP_PKEY_assign_DSA(pkey, dsa);
- PEM_write_PrivateKey(stdout, pkey, passwd2 ?
- EVP_des_cbc() : NULL, NULL, 0, NULL, passwd2);
- fclose(stdout);
- if (debug)
- DSA_print_fp(stdout, dsa, 0);
- }
- /*
- * Return the marbles.
- */
- if (grpkey != NULL)
- OPENSSL_free(grpkey);
- if (pkey_host != NULL)
- EVP_PKEY_free(pkey_host);
- if (pkey_sign != NULL)
- EVP_PKEY_free(pkey_sign);
- if (pkey_iff != NULL)
- EVP_PKEY_free(pkey_iff);
- if (pkey_gq != NULL)
- EVP_PKEY_free(pkey_gq);
- if (pkey_mv != NULL)
- EVP_PKEY_free(pkey_mv);
- #endif /* OPENSSL */
- return (rval);
- }
- #if 0
- /*
- * Generate random MD5 key with password.
- */
- int
- gen_md5(
- char *id /* file name id */
- )
- {
- BIGNUM *key;
- BIGNUM *keyid;
- FILE *str;
- u_char bin[16];
- fprintf(stderr, "Generating MD5 keys...\n");
- str = fheader("MD5key", hostname);
- keyid = BN_new(); key = BN_new();
- BN_rand(keyid, 16, -1, 0);
- BN_rand(key, 128, -1, 0);
- BN_bn2bin(key, bin);
- PEM_write_fp(str, MD5, NULL, bin);
- fclose(str);
- fslink(id, hostname);
- return (1);
- }
- #else
- /*
- * Generate semi-random MD5 keys compatible with NTPv3 and NTPv4
- */
- int
- gen_md5(
- char *id /* file name id */
- )
- {
- u_char md5key[16]; /* MD5 key */
- FILE *str;
- u_int temp = 0; /* Initialize to prevent warnings during compile */
- int i, j;
- fprintf(stderr, "Generating MD5 keys...\n");
- str = fheader("MD5key", hostname);
- ntp_srandom(epoch);
- for (i = 1; i <= MD5KEYS; i++) {
- for (j = 0; j < 16; j++) {
- while (1) {
- temp = ntp_random() & 0xff;
- if (temp == '#')
- continue;
- if (temp > 0x20 && temp < 0x7f)
- break;
- }
- md5key[j] = (u_char)temp;
- }
- md5key[15] = '\0';
- fprintf(str, "%2d MD5 %16s # MD5 key\n", i,
- md5key);
- }
- fclose(str);
- fslink(id, hostname);
- return (1);
- }
- #endif /* OPENSSL */
- #ifdef OPENSSL
- /*
- * Generate RSA public/private key pair
- */
- EVP_PKEY * /* public/private key pair */
- gen_rsa(
- char *id /* file name id */
- )
- {
- EVP_PKEY *pkey; /* private key */
- RSA *rsa; /* RSA parameters and key pair */
- FILE *str;
- fprintf(stderr, "Generating RSA keys (%d bits)...\n", modulus);
- rsa = RSA_generate_key(modulus, 3, cb, "RSA");
- fprintf(stderr, "\n");
- if (rsa == NULL) {
- fprintf(stderr, "RSA generate keys fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (NULL);
- }
- /*
- * For signature encryption it is not necessary that the RSA
- * parameters be strictly groomed and once in a while the
- * modulus turns out to be non-prime. Just for grins, we check
- * the primality.
- */
- if (!RSA_check_key(rsa)) {
- fprintf(stderr, "Invalid RSA key\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- RSA_free(rsa);
- rval = -1;
- return (NULL);
- }
- /*
- * Write the RSA parameters and keys as a RSA private key
- * encoded in PEM.
- */
- str = fheader("RSAkey", hostname);
- pkey = EVP_PKEY_new();
- EVP_PKEY_assign_RSA(pkey, rsa);
- PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
- NULL, 0, NULL, passwd2);
- fclose(str);
- if (debug)
- RSA_print_fp(stdout, rsa, 0);
- fslink(id, hostname);
- return (pkey);
- }
-
- /*
- * Generate DSA public/private key pair
- */
- EVP_PKEY * /* public/private key pair */
- gen_dsa(
- char *id /* file name id */
- )
- {
- EVP_PKEY *pkey; /* private key */
- DSA *dsa; /* DSA parameters */
- u_char seed[20]; /* seed for parameters */
- FILE *str;
- /*
- * Generate DSA parameters.
- */
- fprintf(stderr,
- "Generating DSA parameters (%d bits)...\n", modulus);
- RAND_bytes(seed, sizeof(seed));
- dsa = DSA_generate_parameters(modulus, seed, sizeof(seed), NULL,
- NULL, cb, "DSA");
- fprintf(stderr, "\n");
- if (dsa == NULL) {
- fprintf(stderr, "DSA generate parameters fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (NULL);
- }
- /*
- * Generate DSA keys.
- */
- fprintf(stderr, "Generating DSA keys (%d bits)...\n", modulus);
- if (!DSA_generate_key(dsa)) {
- fprintf(stderr, "DSA generate keys fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- DSA_free(dsa);
- rval = -1;
- return (NULL);
- }
- /*
- * Write the DSA parameters and keys as a DSA private key
- * encoded in PEM.
- */
- str = fheader("DSAkey", hostname);
- pkey = EVP_PKEY_new();
- EVP_PKEY_assign_DSA(pkey, dsa);
- PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
- NULL, 0, NULL, passwd2);
- fclose(str);
- if (debug)
- DSA_print_fp(stdout, dsa, 0);
- fslink(id, hostname);
- return (pkey);
- }
- /*
- * Generate Schnorr (IFF) parameters and keys
- *
- * The Schnorr (IFF)identity scheme is intended for use when
- * certificates are generated by some other trusted certificate
- * authority and the parameters cannot be conveyed in the certificate
- * itself. For this purpose, new generations of IFF values must be
- * securely transmitted to all members of the group before use. There
- * are two kinds of files: server/client files that include private and
- * public parameters and client files that include only public
- * parameters. The scheme is self contained and independent of new
- * generations of host keys, sign keys and certificates.
- *
- * The IFF values hide in a DSA cuckoo structure which uses the same
- * parameters. The values are used by an identity scheme based on DSA
- * cryptography and described in Stimson p. 285. The p is a 512-bit
- * prime, g a generator of Zp* and q a 160-bit prime that divides p - 1
- * and is a qth root of 1 mod p; that is, g^q = 1 mod p. The TA rolls a
- * private random group key b (0 < b < q), then computes public
- * v = g^(q - a). All values except the group key are known to all group
- * members; the group key is known to the group servers, but not the
- * group clients. Alice challenges Bob to confirm identity using the
- * protocol described below.
- */
- EVP_PKEY * /* DSA cuckoo nest */
- gen_iff(
- char *id /* file name id */
- )
- {
- EVP_PKEY *pkey; /* private key */
- DSA *dsa; /* DSA parameters */
- u_char seed[20]; /* seed for parameters */
- BN_CTX *ctx; /* BN working space */
- BIGNUM *b, *r, *k, *u, *v, *w; /* BN temp */
- FILE *str;
- u_int temp;
- /*
- * Generate DSA parameters for use as IFF parameters.
- */
- fprintf(stderr, "Generating IFF parameters (%d bits)...\n",
- modulus);
- RAND_bytes(seed, sizeof(seed));
- dsa = DSA_generate_parameters(modulus, seed, sizeof(seed), NULL,
- NULL, cb, "IFF");
- fprintf(stderr, "\n");
- if (dsa == NULL) {
- fprintf(stderr, "DSA generate parameters fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (NULL);;
- }
- /*
- * Generate the private and public keys. The DSA parameters and
- * these keys are distributed to all members of the group.
- */
- fprintf(stderr, "Generating IFF keys (%d bits)...\n", modulus);
- b = BN_new(); r = BN_new(); k = BN_new();
- u = BN_new(); v = BN_new(); w = BN_new(); ctx = BN_CTX_new();
- BN_rand(b, BN_num_bits(dsa->q), -1, 0); /* a */
- BN_mod(b, b, dsa->q, ctx);
- BN_sub(v, dsa->q, b);
- BN_mod_exp(v, dsa->g, v, dsa->p, ctx); /* g^(q - b) mod p */
- BN_mod_exp(u, dsa->g, b, dsa->p, ctx); /* g^b mod p */
- BN_mod_mul(u, u, v, dsa->p, ctx);
- temp = BN_is_one(u);
- fprintf(stderr,
- "Confirm g^(q - b) g^b = 1 mod p: %s\n", temp == 1 ?
- "yes" : "no");
- if (!temp) {
- BN_free(b); BN_free(r); BN_free(k);
- BN_free(u); BN_free(v); BN_free(w); BN_CTX_free(ctx);
- rval = -1;
- return (NULL);
- }
- dsa->priv_key = BN_dup(b); /* private key */
- dsa->pub_key = BN_dup(v); /* public key */
- /*
- * Here is a trial round of the protocol. First, Alice rolls
- * random r (0 < r < q) and sends it to Bob. She needs only
- * modulus q.
- */
- BN_rand(r, BN_num_bits(dsa->q), -1, 0); /* r */
- BN_mod(r, r, dsa->q, ctx);
- /*
- * Bob rolls random k (0 < k < q), computes y = k + b r mod q
- * and x = g^k mod p, then sends (y, x) to Alice. He needs
- * moduli p, q and the group key b.
- */
- BN_rand(k, BN_num_bits(dsa->q), -1, 0); /* k, 0 < k < q */
- BN_mod(k, k, dsa->q, ctx);
- BN_mod_mul(v, dsa->priv_key, r, dsa->q, ctx); /* b r mod q */
- BN_add(v, v, k);
- BN_mod(v, v, dsa->q, ctx); /* y = k + b r mod q */
- BN_mod_exp(u, dsa->g, k, dsa->p, ctx); /* x = g^k mod p */
- /*
- * Alice computes g^y v^r and verifies the result is equal to x.
- * She needs modulus p, generator g, and the public key v, as
- * well as her original r.
- */
- BN_mod_exp(v, dsa->g, v, dsa->p, ctx); /* g^y mod p */
- BN_mod_exp(w, dsa->pub_key, r, dsa->p, ctx); /* v^r */
- BN_mod_mul(v, w, v, dsa->p, ctx); /* product mod p */
- temp = BN_cmp(u, v);
- fprintf(stderr,
- "Confirm g^k = g^(k + b r) g^(q - b) r: %s\n", temp ==
- 0 ? "yes" : "no");
- BN_free(b); BN_free(r); BN_free(k);
- BN_free(u); BN_free(v); BN_free(w); BN_CTX_free(ctx);
- if (temp != 0) {
- DSA_free(dsa);
- rval = -1;
- return (NULL);
- }
- /*
- * Write the IFF server parameters and keys as a DSA private key
- * encoded in PEM.
- *
- * p modulus p
- * q modulus q
- * g generator g
- * priv_key b
- * public_key v
- */
- str = fheader("IFFpar", trustname);
- pkey = EVP_PKEY_new();
- EVP_PKEY_assign_DSA(pkey, dsa);
- PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
- NULL, 0, NULL, passwd2);
- fclose(str);
- if (debug)
- DSA_print_fp(stdout, dsa, 0);
- fslink(id, trustname);
- return (pkey);
- }
- /*
- * Generate Guillou-Quisquater (GQ) parameters and keys
- *
- * The Guillou-Quisquater (GQ) identity scheme is intended for use when
- * the parameters, keys and certificates are generated by this program.
- * The scheme uses a certificate extension field do convey the public
- * key of a particular group identified by a group key known only to
- * members of the group. The scheme is self contained and independent of
- * new generations of host keys and sign keys.
- *
- * The GQ parameters hide in a RSA cuckoo structure which uses the same
- * parameters. The values are used by an identity scheme based on RSA
- * cryptography and described in Stimson p. 300 (with errors). The 512-
- * bit public modulus is n = p q, where p and q are secret large primes.
- * The TA rolls private random group key b as RSA exponent. These values
- * are known to all group members.
- *
- * When rolling new certificates, a member recomputes the private and
- * public keys. The private key u is a random roll, while the public key
- * is the inverse obscured by the group key v = (u^-1)^b. These values
- * replace the private and public keys normally generated by the RSA
- * scheme. Alice challenges Bob to confirm identity using the protocol
- * described below.
- */
- EVP_PKEY * /* RSA cuckoo nest */
- gen_gqpar(
- char *id /* file name id */
- )
- {
- EVP_PKEY *pkey; /* private key */
- RSA *rsa; /* GQ parameters */
- BN_CTX *ctx; /* BN working space */
- FILE *str;
- /*
- * Generate RSA parameters for use as GQ parameters.
- */
- fprintf(stderr,
- "Generating GQ parameters (%d bits)...\n", modulus);
- rsa = RSA_generate_key(modulus, 3, cb, "GQ");
- fprintf(stderr, "\n");
- if (rsa == NULL) {
- fprintf(stderr, "RSA generate keys fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (NULL);
- }
- /*
- * Generate the group key b, which is saved in the e member of
- * the RSA structure. These values are distributed to all
- * members of the group, but shielded from all other groups. We
- * don't use all the parameters, but set the unused ones to a
- * small number to minimize the file size.
- */
- ctx = BN_CTX_new();
- BN_rand(rsa->e, BN_num_bits(rsa->n), -1, 0); /* b */
- BN_mod(rsa->e, rsa->e, rsa->n, ctx);
- BN_copy(rsa->d, BN_value_one());
- BN_copy(rsa->p, BN_value_one());
- BN_copy(rsa->q, BN_value_one());
- BN_copy(rsa->dmp1, BN_value_one());
- BN_copy(rsa->dmq1, BN_value_one());
- BN_copy(rsa->iqmp, BN_value_one());
- /*
- * Write the GQ parameters as a RSA private key encoded in PEM.
- * The public and private keys are filled in later.
- *
- * n modulus n
- * e group key b
- * (remaining values are not used)
- */
- str = fheader("GQpar", trustname);
- pkey = EVP_PKEY_new();
- EVP_PKEY_assign_RSA(pkey, rsa);
- PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
- NULL, 0, NULL, passwd2);
- fclose(str);
- if (debug)
- RSA_print_fp(stdout, rsa, 0);
- fslink(id, trustname);
- return (pkey);
- }
- /*
- * Update Guillou-Quisquater (GQ) parameters
- */
- EVP_PKEY * /* RSA cuckoo nest */
- gen_gqkey(
- char *id, /* file name id */
- EVP_PKEY *gqpar /* GQ parameters */
- )
- {
- EVP_PKEY *pkey; /* private key */
- RSA *rsa; /* RSA parameters */
- BN_CTX *ctx; /* BN working space */
- BIGNUM *u, *v, *g, *k, *r, *y; /* BN temps */
- FILE *str;
- u_int temp;
- /*
- * Generate GQ keys. Note that the group key b is the e member
- * of
- * the GQ parameters.
- */
- fprintf(stderr, "Updating GQ keys (%d bits)...\n", modulus);
- ctx = BN_CTX_new(); u = BN_new(); v = BN_new();
- g = BN_new(); k = BN_new(); r = BN_new(); y = BN_new();
- /*
- * When generating his certificate, Bob rolls random private key
- * u.
- */
- rsa = gqpar->pkey.rsa;
- BN_rand(u, BN_num_bits(rsa->n), -1, 0); /* u */
- BN_mod(u, u, rsa->n, ctx);
- BN_mod_inverse(v, u, rsa->n, ctx); /* u^-1 mod n */
- BN_mod_mul(k, v, u, rsa->n, ctx);
- /*
- * Bob computes public key v = (u^-1)^b, which is saved in an
- * extension field on his certificate. We check that u^b v =
- * 1 mod n.
- */
- BN_mod_exp(v, v, rsa->e, rsa->n, ctx);
- BN_mod_exp(g, u, rsa->e, rsa->n, ctx); /* u^b */
- BN_mod_mul(g, g, v, rsa->n, ctx); /* u^b (u^-1)^b */
- temp = BN_is_one(g);
- fprintf(stderr,
- "Confirm u^b (u^-1)^b = 1 mod n: %s\n", temp ? "yes" :
- "no");
- if (!temp) {
- BN_free(u); BN_free(v);
- BN_free(g); BN_free(k); BN_free(r); BN_free(y);
- BN_CTX_free(ctx);
- RSA_free(rsa);
- rval = -1;
- return (NULL);
- }
- BN_copy(rsa->p, u); /* private key */
- BN_copy(rsa->q, v); /* public key */
- /*
- * Here is a trial run of the protocol. First, Alice rolls
- * random r (0 < r < n) and sends it to Bob. She needs only
- * modulus n from the parameters.
- */
- BN_rand(r, BN_num_bits(rsa->n), -1, 0); /* r */
- BN_mod(r, r, rsa->n, ctx);
- /*
- * Bob rolls random k (0 < k < n), computes y = k u^r mod n and
- * g = k^b mod n, then sends (y, g) to Alice. He needs modulus n
- * from the parameters and his private key u.
- */
- BN_rand(k, BN_num_bits(rsa->n), -1, 0); /* k */
- BN_mod(k, k, rsa->n, ctx);
- BN_mod_exp(y, rsa->p, r, rsa->n, ctx); /* u^r mod n */
- BN_mod_mul(y, k, y, rsa->n, ctx); /* y = k u^r mod n */
- BN_mod_exp(g, k, rsa->e, rsa->n, ctx); /* g = k^b mod n */
- /*
- * Alice computes v^r y^b mod n and verifies the result is equal
- * to g. She needs modulus n, generator g and group key b from
- * the parameters and Bob's public key v = (u^-1)^b from his
- * certificate.
- */
- BN_mod_exp(v, rsa->q, r, rsa->n, ctx); /* v^r mod n */
- BN_mod_exp(y, y, rsa->e, rsa->n, ctx); /* y^b mod n */
- BN_mod_mul(y, v, y, rsa->n, ctx); /* v^r y^b mod n */
- temp = BN_cmp(y, g);
- fprintf(stderr, "Confirm g^k = v^r y^b mod n: %s\n", temp == 0 ?
- "yes" : "no");
- BN_CTX_free(ctx); BN_free(u); BN_free(v);
- BN_free(g); BN_free(k); BN_free(r); BN_free(y);
- if (temp != 0) {
- RSA_free(rsa);
- rval = -1;
- return (NULL);
- }
- /*
- * Write the GQ parameters and keys as a RSA private key encoded
- * in PEM.
- *
- * n modulus n
- * e group key b
- * p private key u
- * q public key (u^-1)^b
- * (remaining values are not used)
- */
- str = fheader("GQpar", trustname);
- pkey = EVP_PKEY_new();
- EVP_PKEY_assign_RSA(pkey, rsa);
- PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
- NULL, 0, NULL, passwd2);
- fclose(str);
- if (debug)
- RSA_print_fp(stdout, rsa, 0);
- fslink(id, trustname);
- return (pkey);
- }
- /*
- * Generate Mu-Varadharajan (MV) parameters and keys
- *
- * The Mu-Varadharajan (MV) cryptosystem is useful when servers
- * broadcast messages to clients, but clients never send messages to
- * servers. There is one encryption key for the server and a separate
- * decryption key for each client. It operates something like a
- * pay-per-view satellite broadcasting system where the session key is
- * encrypted by the broadcaster and the decryption keys are held in a
- * tamperproof set-top box. We don't use it this way, but read on.
- *
- * The MV parameters and private encryption key hide in a DSA cuckoo
- * structure which uses the same parameters, but generated in a
- * different way. The values are used in an encryption scheme similar to
- * El Gamal cryptography and a polynomial formed from the expansion of
- * product terms (x - x[j]), as described in Mu, Y., and V.
- * Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
- * 223-231. The paper has significant errors and serious omissions.
- *
- * Let q be the product of n distinct primes s'[j] (j = 1...n), where
- * each s'[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
- * that q and each s'[j] divide p - 1 and p has M = n * m + 1
- * significant bits. Let g be a generator of Zp; that is, gcd(g, p - 1)
- * = 1 and g^q = 1 mod p. We do modular arithmetic over Zq and then
- * project into Zp* as exponents of g. Sometimes we have to compute an
- * inverse b^-1 of random b in Zq, but for that purpose we require
- * gcd(b, q) = 1. We expect M to be in the 500-bit range and n
- * relatively small, like 30. Associated with each s'[j] is an element
- * s[j] such that s[j] s'[j] = s'[j] mod q. We find s[j] as the quotient
- * (q + s'[j]) / s'[j]. These are the parameters of the scheme and they
- * are expensive to compute.
- *
- * We set up an instance of the scheme as follows. A set of random
- * values x[j] mod q (j = 1...n), are generated as the zeros of a
- * polynomial of order n. The product terms (x - x[j]) are expanded to
- * form coefficients a[i] mod q (i = 0...n) in powers of x. These are
- * used as exponents of the generator g mod p to generate the private
- * encryption key A. The pair (gbar, ghat) of public server keys and the
- * pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
- * to construct the decryption keys. The devil is in the details.
- *
- * This routine generates a private encryption file including the
- * private encryption key E and public key (gbar, ghat). It then
- * generates decryption files including the private key (xbar[j],
- * xhat[j]) for each client. E is a permutation that encrypts a block
- * y = E x. The jth client computes the inverse permutation E^-1 =
- * gbar^xhat[j] ghat^xbar[j] and decrypts the block x = E^-1 y.
- *
- * The distinguishing characteristic of this scheme is the capability to
- * revoke keys. Included in the calculation of E, gbar and ghat is the
- * product s = prod(s'[j]) (j = 1...n) above. If the factor s'[j] is
- * subsequently removed from the product and E, gbar and ghat
- * recomputed, the jth client will no longer be able to compute E^-1 and
- * thus unable to decrypt the block.
- */
- EVP_PKEY * /* DSA cuckoo nest */
- gen_mv(
- char *id /* file name id */
- )
- {
- EVP_PKEY *pkey, *pkey1; /* private key */
- DSA *dsa; /* DSA parameters */
- DSA *sdsa; /* DSA parameters */
- BN_CTX *ctx; /* BN working space */
- BIGNUM **x; /* polynomial zeros vector */
- BIGNUM **a; /* polynomial coefficient vector */
- BIGNUM **g; /* public key vector */
- BIGNUM **s, **s1; /* private enabling keys */
- BIGNUM **xbar, **xhat; /* private keys vector */
- BIGNUM *b; /* group key */
- BIGNUM *b1; /* inverse group key */
- BIGNUM *ss; /* enabling key */
- BIGNUM *biga; /* master encryption key */
- BIGNUM *bige; /* session encryption key */
- BIGNUM *gbar, *ghat; /* public key */
- BIGNUM *u, *v, *w; /* BN scratch */
- int i, j, n;
- FILE *str;
- u_int temp;
- char ident[20];
- /*
- * Generate MV parameters.
- *
- * The object is to generate a multiplicative group Zp* modulo a
- * prime p and a subset Zq mod q, where q is the product of n
- * distinct primes s'[j] (j = 1...n) and q divides p - 1. We
- * first generate n distinct primes, which may have to be
- * regenerated later. As a practical matter, it is tough to find
- * more than 31 distinct primes for modulus 512 or 61 primes for
- * modulus 1024. The latter can take several hundred iterations
- * and several minutes on a Sun Blade 1000.
- */
- n = nkeys;
- fprintf(stderr,
- "Generating MV parameters for %d keys (%d bits)...\n", n,
- modulus / n);
- ctx = BN_CTX_new(); u = BN_new(); v = BN_new(); w = BN_new();
- b = BN_new(); b1 = BN_new();
- dsa = DSA_new();
- dsa->p = BN_new();
- dsa->q = BN_new();
- dsa->g = BN_new();
- s = malloc((n + 1) * sizeof(BIGNUM));
- s1 = malloc((n + 1) * sizeof(BIGNUM));
- for (j = 1; j <= n; j++)
- s1[j] = BN_new();
- temp = 0;
- for (j = 1; j <= n; j++) {
- while (1) {
- fprintf(stderr, "Birthdays %d\r", temp);
- BN_generate_prime(s1[j], modulus / n, 0, NULL,
- NULL, NULL, NULL);
- for (i = 1; i < j; i++) {
- if (BN_cmp(s1[i], s1[j]) == 0)
- break;
- }
- if (i == j)
- break;
- temp++;
- }
- }
- fprintf(stderr, "Birthday keys rejected %d\n", temp);
- /*
- * Compute the modulus q as the product of the primes. Compute
- * the modulus p as 2 * q + 1 and test p for primality. If p
- * is composite, replace one of the primes with a new distinct
- * one and try again. Note that q will hardly be a secret since
- * we have to reveal p to servers and clients. However,
- * factoring q to find the primes should be adequately hard, as
- * this is the same problem considered hard in RSA. Question: is
- * it as hard to find n small prime factors totalling n bits as
- * it is to find two large prime factors totalling n bits?
- * Remember, the bad guy doesn't know n.
- */
- temp = 0;
- while (1) {
- fprintf(stderr, "Duplicate keys rejected %d\r", ++temp);
- BN_one(dsa->q);
- for (j = 1; j <= n; j++)
- BN_mul(dsa->q, dsa->q, s1[j], ctx);
- BN_copy(dsa->p, dsa->q);
- BN_add(dsa->p, dsa->p, dsa->p);
- BN_add_word(dsa->p, 1);
- if (BN_is_prime(dsa->p, BN_prime_checks, NULL, ctx,
- NULL))
- break;
- j = temp % n + 1;
- while (1) {
- BN_generate_prime(u, modulus / n, 0, 0, NULL,
- NULL, NULL);
- for (i = 1; i <= n; i++) {
- if (BN_cmp(u, s1[i]) == 0)
- break;
- }
- if (i > n)
- break;
- }
- BN_copy(s1[j], u);
- }
- fprintf(stderr, "Duplicate keys rejected %d\n", temp);
- /*
- * Compute the generator g using a random roll such that
- * gcd(g, p - 1) = 1 and g^q = 1. This is a generator of p, not
- * q.
- */
- BN_copy(v, dsa->p);
- BN_sub_word(v, 1);
- while (1) {
- BN_rand(dsa->g, BN_num_bits(dsa->p) - 1, 0, 0);
- BN_mod(dsa->g, dsa->g, dsa->p, ctx);
- BN_gcd(u, dsa->g, v, ctx);
- if (!BN_is_one(u))
- continue;
- BN_mod_exp(u, dsa->g, dsa->q, dsa->p, ctx);
- if (BN_is_one(u))
- break;
- }
- /*
- * Compute s[j] such that s[j] * s'[j] = s'[j] for all j. The
- * easy way to do this is to compute q + s'[j] and divide the
- * result by s'[j]. Exercise for the student: prove the
- * remainder is always zero.
- */
- for (j = 1; j <= n; j++) {
- s[j] = BN_new();
- BN_add(s[j], dsa->q, s1[j]);
- BN_div(s[j], u, s[j], s1[j], ctx);
- }
- /*
- * Setup is now complete. Roll random polynomial roots x[j]
- * (0 < x[j] < q) for all j. While it may not be strictly
- * necessary, Make sure each root has no factors in common with
- * q.
- */
- fprintf(stderr,
- "Generating polynomial coefficients for %d roots (%d bits)\n",
- n, BN_num_bits(dsa->q));
- x = malloc((n + 1) * sizeof(BIGNUM));
- for (j = 1; j <= n; j++) {
- x[j] = BN_new();
- while (1) {
- BN_rand(x[j], BN_num_bits(dsa->q), 0, 0);
- BN_mod(x[j], x[j], dsa->q, ctx);
- BN_gcd(u, x[j], dsa->q, ctx);
- if (BN_is_one(u))
- break;
- }
- }
- /*
- * Generate polynomial coefficients a[i] (i = 0...n) from the
- * expansion of root products (x - x[j]) mod q for all j. The
- * method is a present from Charlie Boncelet.
- */
- a = malloc((n + 1) * sizeof(BIGNUM));
- for (i = 0; i <= n; i++) {
- a[i] = BN_new();
- BN_one(a[i]);
- }
- for (j = 1; j <= n; j++) {
- BN_zero(w);
- for (i = 0; i < j; i++) {
- BN_copy(u, dsa->q);
- BN_mod_mul(v, a[i], x[j], dsa->q, ctx);
- BN_sub(u, u, v);
- BN_add(u, u, w);
- BN_copy(w, a[i]);
- BN_mod(a[i], u, dsa->q, ctx);
- }
- }
- /*
- * Generate g[i] = g^a[i] mod p for all i and the generator g.
- */
- fprintf(stderr, "Generating g[i] parameters\n");
- g = malloc((n + 1) * sizeof(BIGNUM));
- for (i = 0; i <= n; i++) {
- g[i] = BN_new();
- BN_mod_exp(g[i], dsa->g, a[i], dsa->p, ctx);
- }
- /*
- * Verify prod(g[i]^(a[i] x[j]^i)) = 1 for all i, j; otherwise,
- * exit. Note the a[i] x[j]^i exponent is computed mod q, but
- * the g[i] is computed mod p. also note the expression given in
- * the paper is incorrect.
- */
- temp = 1;
- for (j = 1; j <= n; j++) {
- BN_one(u);
- for (i = 0; i <= n; i++) {
- BN_set_word(v, i);
- BN_mod_exp(v, x[j], v, dsa->q, ctx);
- BN_mod_mul(v, v, a[i], dsa->q, ctx);
- BN_mod_exp(v, dsa->g, v, dsa->p, ctx);
- BN_mod_mul(u, u, v, dsa->p, ctx);
- }
- if (!BN_is_one(u))
- temp = 0;
- }
- fprintf(stderr,
- "Confirm prod(g[i]^(x[j]^i)) = 1 for all i, j: %s\n", temp ?
- "yes" : "no");
- if (!temp) {
- rval = -1;
- return (NULL);
- }
- /*
- * Make private encryption key A. Keep it around for awhile,
- * since it is expensive to compute.
- */
- biga = BN_new();
- BN_one(biga);
- for (j = 1; j <= n; j++) {
- for (i = 0; i < n; i++) {
- BN_set_word(v, i);
- BN_mod_exp(v, x[j], v, dsa->q, ctx);
- BN_mod_exp(v, g[i], v, dsa->p, ctx);
- BN_mod_mul(biga, biga, v, dsa->p, ctx);
- }
- }
- /*
- * Roll private random group key b mod q (0 < b < q), where
- * gcd(b, q) = 1 to guarantee b^1 exists, then compute b^-1
- * mod q. If b is changed, the client keys must be recomputed.
- */
- while (1) {
- BN_rand(b, BN_num_bits(dsa->q), 0, 0);
- BN_mod(b, b, dsa->q, ctx);
- BN_gcd(u, b, dsa->q, ctx);
- if (BN_is_one(u))
- break;
- }
- BN_mod_inverse(b1, b, dsa->q, ctx);
- /*
- * Make private client keys (xbar[j], xhat[j]) for all j. Note
- * that the keys for the jth client involve s[j], but not s'[j]
- * or the product s = prod(s'[j]) mod q, which is the enabling
- * key.
- */
- xbar = malloc((n + 1) * sizeof(BIGNUM));
- xhat = malloc((n + 1) * sizeof(BIGNUM));
- for (j = 1; j <= n; j++) {
- xbar[j] = BN_new(); xhat[j] = BN_new();
- BN_zero(xbar[j]);
- BN_set_word(v, n);
- for (i = 1; i <= n; i++) {
- if (i == j)
- continue;
- BN_mod_exp(u, x[i], v, dsa->q, ctx);
- BN_add(xbar[j], xbar[j], u);
- }
- BN_mod_mul(xbar[j], xbar[j], b1, dsa->q, ctx);
- BN_mod_exp(xhat[j], x[j], v, dsa->q, ctx);
- BN_mod_mul(xhat[j], xhat[j], s[j], dsa->q, ctx);
- }
- /*
- * The enabling key is initially q by construction. We can
- * revoke client j by dividing q by s'[j]. The quotient becomes
- * the enabling key s. Note we always have to revoke one key;
- * otherwise, the plaintext and cryptotext would be identical.
- */
- ss = BN_new();
- BN_copy(ss, dsa->q);
- BN_div(ss, u, dsa->q, s1[n], ctx);
- /*
- * Make private server encryption key E = A^s and public server
- * keys gbar = g^s mod p and ghat = g^(s b) mod p. The (gbar,
- * ghat) is the public key provided to the server, which uses it
- * to compute the session encryption key and public key included
- * in its messages. These values must be regenerated if the
- * enabling key is changed.
- */
- bige = BN_new(); gbar = BN_new(); ghat = BN_new();
- BN_mod_exp(bige, biga, ss, dsa->p, ctx);
- BN_mod_exp(gbar, dsa->g, ss, dsa->p, ctx);
- BN_mod_mul(v, ss, b, dsa->q, ctx);
- BN_mod_exp(ghat, dsa->g, v, dsa->p, ctx);
- /*
- * We produce the key media in three steps. The first step is to
- * generate the private values that do not depend on the
- * enabling key. These include the server values p, q, g, b, A
- * and the client values s'[j], xbar[j] and xhat[j] for each j.
- * The p, xbar[j] and xhat[j] values are encoded in private
- * files which are distributed to respective clients. The p, q,
- * g, A and s'[j] values (will be) written to a secret file to
- * be read back later.
- *
- * The secret file (will be) read back at some later time to
- * enable/disable individual keys and generate/regenerate the
- * enabling key s. The p, q, E, gbar and ghat values are written
- * to a secret file to be read back later by the server.
- *
- * The server reads the secret file and rolls the session key
- * k, which is used only once, then computes E^k, gbar^k and
- * ghat^k. The E^k is the session encryption key. The encrypted
- * data, gbar^k and ghat^k are transmtted to clients in an
- * extension field. The client receives the message and computes
- * x = (gbar^k)^xbar[j] (ghat^k)^xhat[j], finds the session
- * encryption key E^k as the inverse x^-1 and decrypts the data.
- */
- BN_copy(dsa->g, bige);
- dsa->priv_key = BN_dup(gbar);
- dsa->pub_key = BN_dup(ghat);
- /*
- * Write the MV server parameters and keys as a DSA private key
- * encoded in PEM.
- *
- * p modulus p
- * q modulus q (used only to generate k)
- * g E mod p
- * priv_key gbar mod p
- * pub_key ghat mod p
- */
- str = fheader("MVpar", trustname);
- pkey = EVP_PKEY_new();
- EVP_PKEY_assign_DSA(pkey, dsa);
- PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
- NULL, 0, NULL, passwd2);
- fclose(str);
- if (debug)
- DSA_print_fp(stdout, dsa, 0);
- fslink(id, trustname);
- /*
- * Write the parameters and private key (xbar[j], xhat[j]) for
- * all j as a DSA private key encoded in PEM. It is used only by
- * the designated recipient(s) who pay a suitably outrageous fee
- * for its use.
- */
- sdsa = DSA_new();
- sdsa->p = BN_dup(dsa->p);
- sdsa->q = BN_dup(BN_value_one());
- sdsa->g = BN_dup(BN_value_one());
- sdsa->priv_key = BN_new();
- sdsa->pub_key = BN_new();
- for (j = 1; j <= n; j++) {
- BN_copy(sdsa->priv_key, xbar[j]);
- BN_copy(sdsa->pub_key, xhat[j]);
- BN_mod_exp(v, dsa->priv_key, sdsa->pub_key, dsa->p,
- ctx);
- BN_mod_exp(u, dsa->pub_key, sdsa->priv_key, dsa->p,
- ctx);
- BN_mod_mul(u, u, v, dsa->p, ctx);
- BN_mod_mul(u, u, dsa->g, dsa->p, ctx);
- BN_free(xbar[j]); BN_free(xhat[j]);
- BN_free(x[j]); BN_free(s[j]); BN_free(s1[j]);
- if (!BN_is_one(u)) {
- fprintf(stderr, "Revoke key %d\n", j);
- continue;
- }
- /*
- * Write the client parameters as a DSA private key
- * encoded in PEM. We don't make links for these.
- *
- * p modulus p
- * priv_key xbar[j] mod q
- * pub_key xhat[j] mod q
- * (remaining values are not used)
- */
- sprintf(ident, "MVkey%d", j);
- str = fheader(ident, trustname);
- pkey1 = EVP_PKEY_new();
- EVP_PKEY_set1_DSA(pkey1, sdsa);
- PEM_write_PrivateKey(str, pkey1, passwd2 ?
- EVP_des_cbc() : NULL, NULL, 0, NULL, passwd2);
- fclose(str);
- fprintf(stderr, "ntpkey_%s_%s.%lu\n", ident, trustname,
- epoch + JAN_1970);
- if (debug)
- DSA_print_fp(stdout, sdsa, 0);
- EVP_PKEY_free(pkey1);
- }
- /*
- * Free the countries.
- */
- for (i = 0; i <= n; i++) {
- BN_free(a[i]);
- BN_free(g[i]);
- }
- BN_free(u); BN_free(v); BN_free(w); BN_CTX_free(ctx);
- BN_free(b); BN_free(b1); BN_free(biga); BN_free(bige);
- BN_free(ss); BN_free(gbar); BN_free(ghat);
- DSA_free(sdsa);
- /*
- * Free the world.
- */
- free(x); free(a); free(g); free(s); free(s1);
- free(xbar); free(xhat);
- return (pkey);
- }
- /*
- * Generate X509v3 scertificate.
- *
- * The certificate consists of the version number, serial number,
- * validity interval, issuer name, subject name and public key. For a
- * self-signed certificate, the issuer name is the same as the subject
- * name and these items are signed using the subject private key. The
- * validity interval extends from the current time to the same time one
- * year hence. For NTP purposes, it is convenient to use the NTP seconds
- * of the current time as the serial number.
- */
- int
- x509 (
- EVP_PKEY *pkey, /* generic signature algorithm */
- const EVP_MD *md, /* generic digest algorithm */
- char *gqpub, /* identity extension (hex string) */
- char *exten /* private cert extension */
- )
- {
- X509 *cert; /* X509 certificate */
- X509_NAME *subj; /* distinguished (common) name */
- X509_EXTENSION *ex; /* X509v3 extension */
- FILE *str; /* file handle */
- ASN1_INTEGER *serial; /* serial number */
- const char *id; /* digest/signature scheme name */
- char pathbuf[MAXFILENAME + 1];
- /*
- * Generate X509 self-signed certificate.
- *
- * Set the certificate serial to the NTP seconds for grins. Set
- * the version to 3. Set the subject name and issuer name to the
- * subject name in the request. Set the initial validity to the
- * current time and the final validity one year hence.
- */
- id = OBJ_nid2sn(md->pkey_type);
- fprintf(stderr, "Generating certificate %s\n", id);
- cert = X509_new();
- X509_set_version(cert, 2L);
- serial = ASN1_INTEGER_new();
- ASN1_INTEGER_set(serial, epoch + JAN_1970);
- X509_set_serialNumber(cert, serial);
- ASN1_INTEGER_free(serial);
- X509_time_adj(X509_get_notBefore(cert), 0L, &epoch);
- X509_time_adj(X509_get_notAfter(cert), YEAR, &epoch);
- subj = X509_get_subject_name(cert);
- X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
- (unsigned char *) hostname, strlen(hostname), -1, 0);
- subj = X509_get_issuer_name(cert);
- X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
- (unsigned char *) trustname, strlen(trustname), -1, 0);
- if (!X509_set_pubkey(cert, pkey)) {
- fprintf(stderr, "Assign key fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- X509_free(cert);
- rval = -1;
- return (0);
- }
- /*
- * Add X509v3 extensions if present. These represent the minimum
- * set defined in RFC3280 less the certificate_policy extension,
- * which is seriously obfuscated in OpenSSL.
- */
- /*
- * The basic_constraints extension CA:TRUE allows servers to
- * sign client certficitates.
- */
- fprintf(stderr, "%s: %s\n", LN_basic_constraints,
- BASIC_CONSTRAINTS);
- ex = X509V3_EXT_conf_nid(NULL, NULL, NID_basic_constraints,
- BASIC_CONSTRAINTS);
- if (!X509_add_ext(cert, ex, -1)) {
- fprintf(stderr, "Add extension field fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (0);
- }
- X509_EXTENSION_free(ex);
- /*
- * The key_usage extension designates the purposes the key can
- * be used for.
- */
- fprintf(stderr, "%s: %s\n", LN_key_usage, KEY_USAGE);
- ex = X509V3_EXT_conf_nid(NULL, NULL, NID_key_usage, KEY_USAGE);
- if (!X509_add_ext(cert, ex, -1)) {
- fprintf(stderr, "Add extension field fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (0);
- }
- X509_EXTENSION_free(ex);
- /*
- * The subject_key_identifier is used for the GQ public key.
- * This should not be controversial.
- */
- if (gqpub != NULL) {
- fprintf(stderr, "%s\n", LN_subject_key_identifier);
- ex = X509V3_EXT_conf_nid(NULL, NULL,
- NID_subject_key_identifier, gqpub);
- if (!X509_add_ext(cert, ex, -1)) {
- fprintf(stderr,
- "Add extension field fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (0);
- }
- X509_EXTENSION_free(ex);
- }
- /*
- * The extended key usage extension is used for special purpose
- * here. The semantics probably do not conform to the designer's
- * intent and will likely change in future.
- *
- * "trustRoot" designates a root authority
- * "private" designates a private certificate
- */
- if (exten != NULL) {
- fprintf(stderr, "%s: %s\n", LN_ext_key_usage, exten);
- ex = X509V3_EXT_conf_nid(NULL, NULL,
- NID_ext_key_usage, exten);
- if (!X509_add_ext(cert, ex, -1)) {
- fprintf(stderr,
- "Add extension field fails\n%s\n",
- ERR_error_string(ERR_get_error(), NULL));
- rval = -1;
- return (0);
- }
- X509_EXTENSION_free(ex);
- }
- /*
- * Sign and verify.
- */
- X509_sign(cert, pkey, md);
- if (!X509_verify(cert, pkey)) {
- fprintf(stderr, "Verify %s certificate fails\n%s\n", id,
- ERR_error_string(ERR_get_error(), NULL));
- X509_free(cert);
- rval = -1;
- return (0);
- }
- /*
- * Write the certificate encoded in PEM.
- */
- sprintf(pathbuf, "%scert", id);
- str = fheader(pathbuf, hostname);
- PEM_write_X509(str, cert);
- fclose(str);
- if (debug)
- X509_print_fp(stdout, cert);
- X509_free(cert);
- fslink("cert", hostname);
- return (1);
- }
- #if 0 /* asn2ntp is not used */
- /*
- * asn2ntp - convert ASN1_TIME time structure to NTP time
- */
- u_long
- asn2ntp (
- ASN1_TIME *asn1time /* pointer to ASN1_TIME structure */
- )
- {
- char *v; /* pointer to ASN1_TIME string */
- struct tm tm; /* time decode structure time */
- /*
- * Extract time string YYMMDDHHMMSSZ from ASN.1 time structure.
- * Note that the YY, MM, DD fields start with one, the HH, MM,
- * SS fiels start with zero and the Z character should be 'Z'
- * for UTC. Also note that years less than 50 map to years
- * greater than 100. Dontcha love ASN.1?
- */
- if (asn1time->length > 13)
- return (-1);
- v = (char *)asn1time->data;
- tm.tm_year = (v[0] - '0') * 10 + v[1] - '0';
- if (tm.tm_year < 50)
- tm.tm_year += 100;
- tm.tm_mon = (v[2] - '0') * 10 + v[3] - '0' - 1;
- tm.tm_mday = (v[4] - '0') * 10 + v[5] - '0';
- tm.tm_hour = (v[6] - '0') * 10 + v[7] - '0';
- tm.tm_min = (v[8] - '0') * 10 + v[9] - '0';
- tm.tm_sec = (v[10] - '0') * 10 + v[11] - '0';
- tm.tm_wday = 0;
- tm.tm_yday = 0;
- tm.tm_isdst = 0;
- return (mktime(&tm) + JAN_1970);
- }
- #endif
- /*
- * Callback routine
- */
- void
- cb (
- int n1, /* arg 1 */
- int n2, /* arg 2 */
- void *chr /* arg 3 */
- )
- {
- switch (n1) {
- case 0:
- d0++;
- fprintf(stderr, "%s %d %d %lu\r", (char *)chr, n1, n2,
- d0);
- break;
- case 1:
- d1++;
- fprintf(stderr, "%s\t\t%d %d %lu\r", (char *)chr, n1,
- n2, d1);
- break;
- case 2:
- d2++;
- fprintf(stderr, "%s\t\t\t\t%d %d %lu\r", (char *)chr,
- n1, n2, d2);
- break;
- case 3:
- d3++;
- fprintf(stderr, "%s\t\t\t\t\t\t%d %d %lu\r",
- (char *)chr, n1, n2, d3);
- break;
- }
- }
- /*
- * Generate key
- */
- EVP_PKEY * /* public/private key pair */
- genkey(
- char *type, /* key type (RSA or DSA) */
- char *id /* file name id */
- )
- {
- if (type == NULL)
- return (NULL);
- if (strcmp(type, "RSA") == 0)
- return (gen_rsa(id));
- else if (strcmp(type, "DSA") == 0)
- return (gen_dsa(id));
- fprintf(stderr, "Invalid %s key type %s\n", id, type);
- rval = -1;
- return (NULL);
- }
- #endif /* OPENSSL */
- /*
- * Generate file header
- */
- FILE *
- fheader (
- const char *id, /* file name id */
- const char *name /* owner name */
- )
- {
- FILE *str; /* file handle */
- sprintf(filename, "ntpkey_%s_%s.%lu", id, name, epoch +
- JAN_1970);
- if ((str = fopen(filename, "w")) == NULL) {
- perror("Write");
- exit (-1);
- }
- fprintf(str, "# %s\n# %s", filename, ctime(&epoch));
- return (str);
- }
- /*
- * Generate symbolic links
- */
- void
- fslink(
- const char *id, /* file name id */
- const char *name /* owner name */
- )
- {
- char linkname[MAXFILENAME]; /* link name */
- int temp;
- sprintf(linkname, "ntpkey_%s_%s", id, name);
- remove(linkname);
- temp = symlink(filename, linkname);
- if (temp < 0)
- perror(id);
- fprintf(stderr, "Generating new %s file and link\n", id);
- fprintf(stderr, "%s->%s\n", linkname, filename);
- }