1dsa(3) OpenSSL dsa(3)
2
6 dsa - Digital Signature Algorithm
7
9 #include <openssl/dsa.h>
10 #include <openssl/engine.h>
11 DSA * DSA_new(void);
13 void DSA_free(DSA *dsa);
14 int DSA_size(const DSA *dsa);
16 DSA * DSA_generate_parameters(int bits, unsigned char *seed,
18 int seed_len, int *counter_ret, unsigned long *h_ret,
19 void (*callback)(int, int, void *), void *cb_arg);
20 DH * DSA_dup_DH(const DSA *r);
22 int DSA_generate_key(DSA *dsa);
24 int DSA_sign(int dummy, const unsigned char *dgst, int len,
26 unsigned char *sigret, unsigned int *siglen, DSA *dsa);
27 int DSA_sign_setup(DSA *dsa, BN_CTX *ctx, BIGNUM **kinvp,
28 BIGNUM **rp);
29 int DSA_verify(int dummy, const unsigned char *dgst, int len,
30 const unsigned char *sigbuf, int siglen, DSA *dsa);
31 void DSA_set_default_method(const DSA_METHOD *meth);
33 const DSA_METHOD *DSA_get_default_method(void);
34 int DSA_set_method(DSA *dsa, const DSA_METHOD *meth);
35 DSA *DSA_new_method(ENGINE *engine);
36 const DSA_METHOD *DSA_OpenSSL(void);
37 int DSA_get_ex_new_index(long argl, char *argp, int (*new_func)(),
39 int (*dup_func)(), void (*free_func)());
40 int DSA_set_ex_data(DSA *d, int idx, char *arg);
41 char *DSA_get_ex_data(DSA *d, int idx);
42 DSA_SIG *DSA_SIG_new(void);
44 void DSA_SIG_free(DSA_SIG *a);
45 int i2d_DSA_SIG(const DSA_SIG *a, unsigned char **pp);
46 DSA_SIG *d2i_DSA_SIG(DSA_SIG **v, unsigned char **pp, long length);
47 DSA_SIG *DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);
49 int DSA_do_verify(const unsigned char *dgst, int dgst_len,
50 DSA_SIG *sig, DSA *dsa);
51 DSA * d2i_DSAPublicKey(DSA **a, unsigned char **pp, long length);
53 DSA * d2i_DSAPrivateKey(DSA **a, unsigned char **pp, long length);
54 DSA * d2i_DSAparams(DSA **a, unsigned char **pp, long length);
55 int i2d_DSAPublicKey(const DSA *a, unsigned char **pp);
56 int i2d_DSAPrivateKey(const DSA *a, unsigned char **pp);
57 int i2d_DSAparams(const DSA *a,unsigned char **pp);
58 int DSAparams_print(BIO *bp, const DSA *x);
60 int DSAparams_print_fp(FILE *fp, const DSA *x);
61 int DSA_print(BIO *bp, const DSA *x, int off);
62 int DSA_print_fp(FILE *bp, const DSA *x, int off);
63
65 These functions implement the Digital Signature Algorithm (DSA). The
66 generation of shared DSA parameters is described in DSA_generate_param‐
67 eters(3); DSA_generate_key(3) describes how to generate a signature
68 key. Signature generation and verification are described in
69 DSA_sign(3).
70 The DSA structure consists of several BIGNUM components.
72 struct
74 {
75 BIGNUM *p; // prime number (public)
76 BIGNUM *q; // 160-bit subprime, q ⎪ p-1 (public)
77 BIGNUM *g; // generator of subgroup (public)
78 BIGNUM *priv_key; // private key x
79 BIGNUM *pub_key; // public key y = g^x
80 // ...
81 }
82 DSA;
83 In public keys, priv_key is NULL.
85 Note that DSA keys may use non-standard DSA_METHOD implementations,
87 either directly or by the use of ENGINE modules. In some cases (eg. an
88 ENGINE providing support for hardware-embedded keys), these BIGNUM val‐
89 ues will not be used by the implementation or may be used for alterna‐
90 tive data storage. For this reason, applications should generally avoid
91 using DSA structure elements directly and instead use API functions to
92 query or modify keys.
93
95 US Federal Information Processing Standard FIPS 186 (Digital Signature
96 Standard, DSS), ANSI X9.30
97
99 bn(3), dh(3), err(3), rand(3), rsa(3), sha(3), engine(3), DSA_new(3),
100 DSA_size(3), DSA_generate_parameters(3), DSA_dup_DH(3), DSA_gener‐
101 ate_key(3), DSA_sign(3), DSA_set_method(3), DSA_get_ex_new_index(3),
102 RSA_print(3)
1030.9.8b 2002-08-05 dsa(3)