+
+static int pkey_ecd_digestsign(EVP_MD_CTX *ctx, unsigned char *sig,
+ size_t *siglen, const unsigned char *tbs,
+ size_t tbslen)
+{
+ const X25519_KEY *edkey = EVP_MD_CTX_pkey_ctx(ctx)->pkey->pkey.ptr;
+
+ if (sig == NULL) {
+ *siglen = ED25519_SIGSIZE;
+ return 1;
+ }
+ if (*siglen < ED25519_SIGSIZE) {
+ ECerr(EC_F_PKEY_ECD_DIGESTSIGN, EC_R_BUFFER_TOO_SMALL);
+ return 0;
+ }
+
+ if (ED25519_sign(sig, tbs, tbslen, edkey->pubkey, edkey->privkey) == 0)
+ return 0;
+ *siglen = ED25519_SIGSIZE;
+ return 1;
+}
+
+static int pkey_ecd_digestverify(EVP_MD_CTX *ctx, const unsigned char *sig,
+ size_t siglen, const unsigned char *tbs,
+ size_t tbslen)
+{
+ const X25519_KEY *edkey = EVP_MD_CTX_pkey_ctx(ctx)->pkey->pkey.ptr;
+
+ if (siglen != ED25519_SIGSIZE)
+ return 0;
+
+ return ED25519_verify(tbs, tbslen, sig, edkey->pubkey);
+}
+
+static int pkey_ecd_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
+{
+ switch (type) {
+ case EVP_PKEY_CTRL_MD:
+ /* Only NULL allowed as digest */
+ if (p2 == NULL)
+ return 1;
+ ECerr(EC_F_PKEY_ECD_CTRL, EC_R_INVALID_DIGEST_TYPE);
+ return 0;
+
+ case EVP_PKEY_CTRL_DIGESTINIT:
+ return 1;
+ }
+ return -2;
+}
+
+const EVP_PKEY_METHOD ed25519_pkey_meth = {
+ NID_ED25519, EVP_PKEY_FLAG_SIGCTX_CUSTOM,
+ 0, 0, 0, 0, 0, 0,
+ pkey_ecx_keygen,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ pkey_ecd_ctrl,
+ 0,
+ pkey_ecd_digestsign,
+ pkey_ecd_digestverify
+};