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48  *
49  * This product includes cryptographic software written by Eric Young
50  * (eay@cryptsoft.com).  This product includes software written by Tim
51  * Hudson (tjh@cryptsoft.com). */
52 
53 #ifndef OPENSSL_HEADER_ECDSA_H
54 #define OPENSSL_HEADER_ECDSA_H
55 
56 #include <openssl/base.h>
57 
58 #include <openssl/ec_key.h>
59 
60 #if defined(__cplusplus)
61 extern "C" {
62 #endif
63 
64 
65 // ECDSA contains functions for signing and verifying with the Digital Signature
66 // Algorithm over elliptic curves.
67 
68 
69 // Signing and verifying.
70 
71 // ECDSA_sign signs |digest_len| bytes from |digest| with |key| and writes the
72 // resulting signature to |sig|, which must have |ECDSA_size(key)| bytes of
73 // space. On successful exit, |*sig_len| is set to the actual number of bytes
74 // written. The |type| argument should be zero. It returns one on success and
75 // zero otherwise.
76 OPENSSL_EXPORT int ECDSA_sign(int type, const uint8_t *digest,
77                               size_t digest_len, uint8_t *sig,
78                               unsigned int *sig_len, const EC_KEY *key);
79 
80 // ECDSA_verify verifies that |sig_len| bytes from |sig| constitute a valid
81 // signature by |key| of |digest|. (The |type| argument should be zero.) It
82 // returns one on success or zero if the signature is invalid or an error
83 // occurred.
84 OPENSSL_EXPORT int ECDSA_verify(int type, const uint8_t *digest,
85                                 size_t digest_len, const uint8_t *sig,
86                                 size_t sig_len, const EC_KEY *key);
87 
88 // ECDSA_size returns the maximum size of an ECDSA signature using |key|. It
89 // returns zero if |key| is NULL or if it doesn't have a group set.
90 OPENSSL_EXPORT size_t ECDSA_size(const EC_KEY *key);
91 
92 
93 // Low-level signing and verification.
94 //
95 // Low-level functions handle signatures as |ECDSA_SIG| structures which allow
96 // the two values in an ECDSA signature to be handled separately.
97 
98 struct ecdsa_sig_st {
99   BIGNUM *r;
100   BIGNUM *s;
101 };
102 
103 // ECDSA_SIG_new returns a fresh |ECDSA_SIG| structure or NULL on error.
104 OPENSSL_EXPORT ECDSA_SIG *ECDSA_SIG_new(void);
105 
106 // ECDSA_SIG_free frees |sig| its member |BIGNUM|s.
107 OPENSSL_EXPORT void ECDSA_SIG_free(ECDSA_SIG *sig);
108 
109 // ECDSA_SIG_get0_r returns the r component of |sig|.
110 OPENSSL_EXPORT const BIGNUM *ECDSA_SIG_get0_r(const ECDSA_SIG *sig);
111 
112 // ECDSA_SIG_get0_s returns the s component of |sig|.
113 OPENSSL_EXPORT const BIGNUM *ECDSA_SIG_get0_s(const ECDSA_SIG *sig);
114 
115 // ECDSA_SIG_get0 sets |*out_r| and |*out_s|, if non-NULL, to the two
116 // components of |sig|.
117 OPENSSL_EXPORT void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **out_r,
118                                    const BIGNUM **out_s);
119 
120 // ECDSA_SIG_set0 sets |sig|'s components to |r| and |s|, neither of which may
121 // be NULL. On success, it takes ownership of each argument and returns one.
122 // Otherwise, it returns zero.
123 OPENSSL_EXPORT int ECDSA_SIG_set0(ECDSA_SIG *sig, BIGNUM *r, BIGNUM *s);
124 
125 // ECDSA_do_sign signs |digest_len| bytes from |digest| with |key| and returns
126 // the resulting signature structure, or NULL on error.
127 OPENSSL_EXPORT ECDSA_SIG *ECDSA_do_sign(const uint8_t *digest,
128                                         size_t digest_len, const EC_KEY *key);
129 
130 // ECDSA_do_verify verifies that |sig| constitutes a valid signature by |key|
131 // of |digest|. It returns one on success or zero if the signature is invalid
132 // or on error.
133 OPENSSL_EXPORT int ECDSA_do_verify(const uint8_t *digest, size_t digest_len,
134                                    const ECDSA_SIG *sig, const EC_KEY *key);
135 
136 
137 // ASN.1 functions.
138 
139 // ECDSA_SIG_parse parses a DER-encoded ECDSA-Sig-Value structure from |cbs| and
140 // advances |cbs|. It returns a newly-allocated |ECDSA_SIG| or NULL on error.
141 OPENSSL_EXPORT ECDSA_SIG *ECDSA_SIG_parse(CBS *cbs);
142 
143 // ECDSA_SIG_from_bytes parses |in| as a DER-encoded ECDSA-Sig-Value structure.
144 // It returns a newly-allocated |ECDSA_SIG| structure or NULL on error.
145 OPENSSL_EXPORT ECDSA_SIG *ECDSA_SIG_from_bytes(const uint8_t *in,
146                                                size_t in_len);
147 
148 // ECDSA_SIG_marshal marshals |sig| as a DER-encoded ECDSA-Sig-Value and appends
149 // the result to |cbb|. It returns one on success and zero on error.
150 OPENSSL_EXPORT int ECDSA_SIG_marshal(CBB *cbb, const ECDSA_SIG *sig);
151 
152 // ECDSA_SIG_to_bytes marshals |sig| as a DER-encoded ECDSA-Sig-Value and, on
153 // success, sets |*out_bytes| to a newly allocated buffer containing the result
154 // and returns one. Otherwise, it returns zero. The result should be freed with
155 // |OPENSSL_free|.
156 OPENSSL_EXPORT int ECDSA_SIG_to_bytes(uint8_t **out_bytes, size_t *out_len,
157                                       const ECDSA_SIG *sig);
158 
159 // ECDSA_SIG_max_len returns the maximum length of a DER-encoded ECDSA-Sig-Value
160 // structure for a group whose order is represented in |order_len| bytes, or
161 // zero on overflow.
162 OPENSSL_EXPORT size_t ECDSA_SIG_max_len(size_t order_len);
163 
164 
165 // Deprecated functions.
166 
167 // d2i_ECDSA_SIG parses an ASN.1, DER-encoded, signature from |len| bytes at
168 // |*inp|. If |out| is not NULL then, on exit, a pointer to the result is in
169 // |*out|. Note that, even if |*out| is already non-NULL on entry, it will not
170 // be written to. Rather, a fresh |ECDSA_SIG| is allocated and the previous one
171 // is freed. On successful exit, |*inp| is advanced past the DER structure. It
172 // returns the result or NULL on error.
173 OPENSSL_EXPORT ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **out, const uint8_t **inp,
174                                         long len);
175 
176 // i2d_ECDSA_SIG marshals a signature from |sig| to an ASN.1, DER
177 // structure. If |outp| is not NULL then the result is written to |*outp| and
178 // |*outp| is advanced just past the output. It returns the number of bytes in
179 // the result, whether written or not, or a negative value on error.
180 OPENSSL_EXPORT int i2d_ECDSA_SIG(const ECDSA_SIG *sig, uint8_t **outp);
181 
182 
183 #if defined(__cplusplus)
184 }  // extern C
185 
186 extern "C++" {
187 
188 BSSL_NAMESPACE_BEGIN
189 
190 BORINGSSL_MAKE_DELETER(ECDSA_SIG, ECDSA_SIG_free)
191 
192 BSSL_NAMESPACE_END
193 
194 }  // extern C++
195 
196 #endif
197 
198 #define ECDSA_R_BAD_SIGNATURE 100
199 #define ECDSA_R_MISSING_PARAMETERS 101
200 #define ECDSA_R_NEED_NEW_SETUP_VALUES 102
201 #define ECDSA_R_NOT_IMPLEMENTED 103
202 #define ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED 104
203 #define ECDSA_R_ENCODE_ERROR 105
204 
205 #endif  // OPENSSL_HEADER_ECDSA_H
206