diff --git a/include/picotls.h b/include/picotls.h
index ee3b941..fc605b7 100644
--- a/include/picotls.h
+++ b/include/picotls.h
@@ -124,6 +124,7 @@
 #define PTLS_SIGNATURE_RSA_PSS_RSAE_SHA256 0x0804
 #define PTLS_SIGNATURE_RSA_PSS_RSAE_SHA384 0x0805
 #define PTLS_SIGNATURE_RSA_PSS_RSAE_SHA512 0x0806
+#define PTLS_SIGNATURE_ED25519 0x0807
 
 /* ESNI */
 #define PTLS_ESNI_VERSION_DRAFT03 0xff02
diff --git a/lib/openssl.c b/lib/openssl.c
index 3221a7e..16f4f9e 100644
--- a/lib/openssl.c
+++ b/lib/openssl.c
@@ -624,38 +624,61 @@
         ret = PTLS_ERROR_NO_MEMORY;
         goto Exit;
     }
+
     if (EVP_DigestSignInit(ctx, &pkey_ctx, md, NULL, key) != 1) {
         ret = PTLS_ERROR_LIBRARY;
         goto Exit;
     }
-    if (EVP_PKEY_id(key) == EVP_PKEY_RSA) {
-        if (EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING) != 1) {
+
+#if defined EVP_PKEY_ED25519
+    if (EVP_PKEY_id(key) == EVP_PKEY_ED25519)
+    {
+        if (EVP_DigestSign(ctx, NULL, &siglen, input.base, input.len) != 1) {
             ret = PTLS_ERROR_LIBRARY;
             goto Exit;
         }
-        if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, -1) != 1) {
-            ret = PTLS_ERROR_LIBRARY;
+
+        if ((ret = ptls_buffer_reserve(outbuf, siglen)) != 0)
             goto Exit;
-        }
-        if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, EVP_sha256()) != 1) {
+        
+        if (EVP_DigestSign(ctx, outbuf->base + outbuf->off, &siglen, input.base, input.len) != 1) {
             ret = PTLS_ERROR_LIBRARY;
             goto Exit;
         }
     }
-    if (EVP_DigestSignUpdate(ctx, input.base, input.len) != 1) {
-        ret = PTLS_ERROR_LIBRARY;
-        goto Exit;
+    else 
+#endif
+    {
+        if (EVP_PKEY_id(key) == EVP_PKEY_RSA) {
+            if (EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING) != 1) {
+                ret = PTLS_ERROR_LIBRARY;
+                goto Exit;
+            }
+            if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, -1) != 1) {
+                ret = PTLS_ERROR_LIBRARY;
+                goto Exit;
+            }
+            if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, EVP_sha256()) != 1) {
+                ret = PTLS_ERROR_LIBRARY;
+                goto Exit;
+            }
+        }
+        if (EVP_DigestSignUpdate(ctx, input.base, input.len) != 1) {
+            ret = PTLS_ERROR_LIBRARY;
+            goto Exit;
+        }
+        if (EVP_DigestSignFinal(ctx, NULL, &siglen) != 1) {
+            ret = PTLS_ERROR_LIBRARY;
+            goto Exit;
+        }
+        if ((ret = ptls_buffer_reserve(outbuf, siglen)) != 0)
+            goto Exit;
+        if (EVP_DigestSignFinal(ctx, outbuf->base + outbuf->off, &siglen) != 1) {
+            ret = PTLS_ERROR_LIBRARY;
+            goto Exit;
+        }
     }
-    if (EVP_DigestSignFinal(ctx, NULL, &siglen) != 1) {
-        ret = PTLS_ERROR_LIBRARY;
-        goto Exit;
-    }
-    if ((ret = ptls_buffer_reserve(outbuf, siglen)) != 0)
-        goto Exit;
-    if (EVP_DigestSignFinal(ctx, outbuf->base + outbuf->off, &siglen) != 1) {
-        ret = PTLS_ERROR_LIBRARY;
-        goto Exit;
-    }
+
     outbuf->off += siglen;
 
     ret = 0;
@@ -964,7 +987,7 @@
     return d2i_X509(NULL, &p, (long)vec.len);
 }
 
-static int verify_sign(void *verify_ctx, ptls_iovec_t data, ptls_iovec_t signature)
+static int verify_sign(void *verify_ctx, ptls_iovec_t data, ptls_iovec_t signature, const EVP_MD *md)
 {
     EVP_PKEY *key = verify_ctx;
     EVP_MD_CTX *ctx = NULL;
@@ -978,32 +1001,46 @@
         ret = PTLS_ERROR_NO_MEMORY;
         goto Exit;
     }
-    if (EVP_DigestVerifyInit(ctx, &pkey_ctx, EVP_sha256(), NULL, key) != 1) {
+    if (EVP_DigestVerifyInit(ctx, &pkey_ctx, md, NULL, key) != 1) {
         ret = PTLS_ERROR_LIBRARY;
         goto Exit;
     }
-    if (EVP_PKEY_id(key) == EVP_PKEY_RSA) {
-        if (EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING) != 1) {
-            ret = PTLS_ERROR_LIBRARY;
-            goto Exit;
-        }
-        if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, -1) != 1) {
-            ret = PTLS_ERROR_LIBRARY;
-            goto Exit;
-        }
-        if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, EVP_sha256()) != 1) {
+
+#if defined EVP_PKEY_ED25519
+    if (EVP_PKEY_id(key) == EVP_PKEY_ED25519)
+    {
+        if (EVP_DigestVerify(ctx, signature.base, signature.len, data.base, data.len) != 1) {
             ret = PTLS_ERROR_LIBRARY;
             goto Exit;
         }
     }
-    if (EVP_DigestVerifyUpdate(ctx, data.base, data.len) != 1) {
-        ret = PTLS_ERROR_LIBRARY;
-        goto Exit;
+    else
+#endif
+    {
+        if (EVP_PKEY_id(key) == EVP_PKEY_RSA) {
+            if (EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING) != 1) {
+                ret = PTLS_ERROR_LIBRARY;
+                goto Exit;
+            }
+            if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, -1) != 1) {
+                ret = PTLS_ERROR_LIBRARY;
+                goto Exit;
+            }
+            if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, EVP_sha256()) != 1) {
+                ret = PTLS_ERROR_LIBRARY;
+                goto Exit;
+            }
+        }
+        if (EVP_DigestVerifyUpdate(ctx, data.base, data.len) != 1) {
+            ret = PTLS_ERROR_LIBRARY;
+            goto Exit;
+        }
+        if (EVP_DigestVerifyFinal(ctx, signature.base, signature.len) != 1) {
+            ret = PTLS_ALERT_DECRYPT_ERROR;
+            goto Exit;
+        }
     }
-    if (EVP_DigestVerifyFinal(ctx, signature.base, signature.len) != 1) {
-        ret = PTLS_ALERT_DECRYPT_ERROR;
-        goto Exit;
-    }
+
     ret = 0;
 
 Exit:
@@ -1052,6 +1089,11 @@
         }
         EC_KEY_free(eckey);
     } break;
+#if defined EVP_PKEY_ED25519
+    case EVP_PKEY_ED25519:
+        PUSH_SCHEME(PTLS_SIGNATURE_ED25519, EVP_sha512());
+        break;
+#endif
     default:
         return PTLS_ERROR_INCOMPATIBLE_KEY;
     }
@@ -1200,7 +1242,7 @@
     return ret;
 }
 
-static int verify_cert(ptls_verify_certificate_t *_self, ptls_t *tls, int (**verifier)(void *, ptls_iovec_t, ptls_iovec_t),
+static int verify_cert(ptls_verify_certificate_t *_self, ptls_t *tls, int (**verifier)(void *, ptls_iovec_t, ptls_iovec_t, const EVP_MD *),
                        void **verify_data, ptls_iovec_t *certs, size_t num_certs)
 {
     ptls_openssl_verify_certificate_t *self = (ptls_openssl_verify_certificate_t *)_self;
@@ -1286,7 +1328,7 @@
     return NULL;
 }
 
-static int verify_raw_cert(ptls_verify_certificate_t *_self, ptls_t *tls, int (**verifier)(void *, ptls_iovec_t, ptls_iovec_t),
+static int verify_raw_cert(ptls_verify_certificate_t *_self, ptls_t *tls, int (**verifier)(void *, ptls_iovec_t, ptls_iovec_t, const EVP_MD *),
                            void **verify_data, ptls_iovec_t *certs, size_t num_certs)
 {
     ptls_openssl_raw_pubkey_verify_certificate_t *self = (ptls_openssl_raw_pubkey_verify_certificate_t *)_self;
diff --git a/t/openssl.c b/t/openssl.c
index fb52775..f4d0be0 100644
--- a/t/openssl.c
+++ b/t/openssl.c
@@ -170,6 +170,31 @@
     EVP_PKEY_free(pkey);
 }
 
+static void test_ed25519_sign(void)
+{
+    EVP_PKEY *pkey = NULL;
+
+    { /* create pkey */
+        EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL);
+        EVP_PKEY_keygen_init(pctx);
+        EVP_PKEY_keygen(pctx, &pkey);
+        EVP_PKEY_CTX_free(pctx);
+    }
+
+    const char *message = "hello world";
+    ptls_buffer_t sigbuf;
+  
+    uint8_t sigbuf_small[1024];
+
+    ptls_buffer_init(&sigbuf, sigbuf_small, sizeof(sigbuf_small));
+    ok(do_sign(pkey, &sigbuf, ptls_iovec_init(message, strlen(message)), NULL) == 0);
+    EVP_PKEY_up_ref(pkey);
+    ok(verify_sign(pkey, ptls_iovec_init(message, strlen(message)), ptls_iovec_init(sigbuf.base, sigbuf.off), NULL) == 0);
+
+    ptls_buffer_dispose(&sigbuf);
+    EVP_PKEY_free(pkey);
+}
+
 static X509 *x509_from_pem(const char *pem)
 {
     BIO *bio = BIO_new_mem_buf((void *)pem, (int)strlen(pem));
@@ -308,6 +333,7 @@
 
     subtest("rsa-sign", test_rsa_sign);
     subtest("ecdsa-sign", test_ecdsa_sign);
+    subtest("ed25519-sign", test_ed25519_sign);
     subtest("cert-verify", test_cert_verify);
     subtest("picotls", test_picotls);
     test_picotls_esni(esni_private_keys);