1*2175Sjp161948=pod 2*2175Sjp161948 3*2175Sjp161948=head1 NAME 4*2175Sjp161948 5*2175Sjp161948dsa - Digital Signature Algorithm 6*2175Sjp161948 7*2175Sjp161948=head1 SYNOPSIS 8*2175Sjp161948 9*2175Sjp161948 #include <openssl/dsa.h> 10*2175Sjp161948 #include <openssl/engine.h> 11*2175Sjp161948 12*2175Sjp161948 DSA * DSA_new(void); 13*2175Sjp161948 void DSA_free(DSA *dsa); 14*2175Sjp161948 15*2175Sjp161948 int DSA_size(const DSA *dsa); 16*2175Sjp161948 17*2175Sjp161948 DSA * DSA_generate_parameters(int bits, unsigned char *seed, 18*2175Sjp161948 int seed_len, int *counter_ret, unsigned long *h_ret, 19*2175Sjp161948 void (*callback)(int, int, void *), void *cb_arg); 20*2175Sjp161948 21*2175Sjp161948 DH * DSA_dup_DH(const DSA *r); 22*2175Sjp161948 23*2175Sjp161948 int DSA_generate_key(DSA *dsa); 24*2175Sjp161948 25*2175Sjp161948 int DSA_sign(int dummy, const unsigned char *dgst, int len, 26*2175Sjp161948 unsigned char *sigret, unsigned int *siglen, DSA *dsa); 27*2175Sjp161948 int DSA_sign_setup(DSA *dsa, BN_CTX *ctx, BIGNUM **kinvp, 28*2175Sjp161948 BIGNUM **rp); 29*2175Sjp161948 int DSA_verify(int dummy, const unsigned char *dgst, int len, 30*2175Sjp161948 const unsigned char *sigbuf, int siglen, DSA *dsa); 31*2175Sjp161948 32*2175Sjp161948 void DSA_set_default_method(const DSA_METHOD *meth); 33*2175Sjp161948 const DSA_METHOD *DSA_get_default_method(void); 34*2175Sjp161948 int DSA_set_method(DSA *dsa, const DSA_METHOD *meth); 35*2175Sjp161948 DSA *DSA_new_method(ENGINE *engine); 36*2175Sjp161948 const DSA_METHOD *DSA_OpenSSL(void); 37*2175Sjp161948 38*2175Sjp161948 int DSA_get_ex_new_index(long argl, char *argp, int (*new_func)(), 39*2175Sjp161948 int (*dup_func)(), void (*free_func)()); 40*2175Sjp161948 int DSA_set_ex_data(DSA *d, int idx, char *arg); 41*2175Sjp161948 char *DSA_get_ex_data(DSA *d, int idx); 42*2175Sjp161948 43*2175Sjp161948 DSA_SIG *DSA_SIG_new(void); 44*2175Sjp161948 void DSA_SIG_free(DSA_SIG *a); 45*2175Sjp161948 int i2d_DSA_SIG(const DSA_SIG *a, unsigned char **pp); 46*2175Sjp161948 DSA_SIG *d2i_DSA_SIG(DSA_SIG **v, unsigned char **pp, long length); 47*2175Sjp161948 48*2175Sjp161948 DSA_SIG *DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa); 49*2175Sjp161948 int DSA_do_verify(const unsigned char *dgst, int dgst_len, 50*2175Sjp161948 DSA_SIG *sig, DSA *dsa); 51*2175Sjp161948 52*2175Sjp161948 DSA * d2i_DSAPublicKey(DSA **a, unsigned char **pp, long length); 53*2175Sjp161948 DSA * d2i_DSAPrivateKey(DSA **a, unsigned char **pp, long length); 54*2175Sjp161948 DSA * d2i_DSAparams(DSA **a, unsigned char **pp, long length); 55*2175Sjp161948 int i2d_DSAPublicKey(const DSA *a, unsigned char **pp); 56*2175Sjp161948 int i2d_DSAPrivateKey(const DSA *a, unsigned char **pp); 57*2175Sjp161948 int i2d_DSAparams(const DSA *a,unsigned char **pp); 58*2175Sjp161948 59*2175Sjp161948 int DSAparams_print(BIO *bp, const DSA *x); 60*2175Sjp161948 int DSAparams_print_fp(FILE *fp, const DSA *x); 61*2175Sjp161948 int DSA_print(BIO *bp, const DSA *x, int off); 62*2175Sjp161948 int DSA_print_fp(FILE *bp, const DSA *x, int off); 63*2175Sjp161948 64*2175Sjp161948=head1 DESCRIPTION 65*2175Sjp161948 66*2175Sjp161948These functions implement the Digital Signature Algorithm (DSA). The 67*2175Sjp161948generation of shared DSA parameters is described in 68*2175Sjp161948L<DSA_generate_parameters(3)|DSA_generate_parameters(3)>; 69*2175Sjp161948L<DSA_generate_key(3)|DSA_generate_key(3)> describes how to 70*2175Sjp161948generate a signature key. Signature generation and verification are 71*2175Sjp161948described in L<DSA_sign(3)|DSA_sign(3)>. 72*2175Sjp161948 73*2175Sjp161948The B<DSA> structure consists of several BIGNUM components. 74*2175Sjp161948 75*2175Sjp161948 struct 76*2175Sjp161948 { 77*2175Sjp161948 BIGNUM *p; // prime number (public) 78*2175Sjp161948 BIGNUM *q; // 160-bit subprime, q | p-1 (public) 79*2175Sjp161948 BIGNUM *g; // generator of subgroup (public) 80*2175Sjp161948 BIGNUM *priv_key; // private key x 81*2175Sjp161948 BIGNUM *pub_key; // public key y = g^x 82*2175Sjp161948 // ... 83*2175Sjp161948 } 84*2175Sjp161948 DSA; 85*2175Sjp161948 86*2175Sjp161948In public keys, B<priv_key> is NULL. 87*2175Sjp161948 88*2175Sjp161948Note that DSA keys may use non-standard B<DSA_METHOD> implementations, 89*2175Sjp161948either directly or by the use of B<ENGINE> modules. In some cases (eg. an 90*2175Sjp161948ENGINE providing support for hardware-embedded keys), these BIGNUM values 91*2175Sjp161948will not be used by the implementation or may be used for alternative data 92*2175Sjp161948storage. For this reason, applications should generally avoid using DSA 93*2175Sjp161948structure elements directly and instead use API functions to query or 94*2175Sjp161948modify keys. 95*2175Sjp161948 96*2175Sjp161948=head1 CONFORMING TO 97*2175Sjp161948 98*2175Sjp161948US Federal Information Processing Standard FIPS 186 (Digital Signature 99*2175Sjp161948Standard, DSS), ANSI X9.30 100*2175Sjp161948 101*2175Sjp161948=head1 SEE ALSO 102*2175Sjp161948 103*2175Sjp161948L<bn(3)|bn(3)>, L<dh(3)|dh(3)>, L<err(3)|err(3)>, L<rand(3)|rand(3)>, 104*2175Sjp161948L<rsa(3)|rsa(3)>, L<sha(3)|sha(3)>, L<engine(3)|engine(3)>, 105*2175Sjp161948L<DSA_new(3)|DSA_new(3)>, 106*2175Sjp161948L<DSA_size(3)|DSA_size(3)>, 107*2175Sjp161948L<DSA_generate_parameters(3)|DSA_generate_parameters(3)>, 108*2175Sjp161948L<DSA_dup_DH(3)|DSA_dup_DH(3)>, 109*2175Sjp161948L<DSA_generate_key(3)|DSA_generate_key(3)>, 110*2175Sjp161948L<DSA_sign(3)|DSA_sign(3)>, L<DSA_set_method(3)|DSA_set_method(3)>, 111*2175Sjp161948L<DSA_get_ex_new_index(3)|DSA_get_ex_new_index(3)>, 112*2175Sjp161948L<RSA_print(3)|RSA_print(3)> 113*2175Sjp161948 114*2175Sjp161948=cut 115