diff --git a/src/server.c b/src/server.c
index 5a8c1cc..da40ca3 100644
--- a/src/server.c
+++ b/src/server.c
@@ -68,7 +68,7 @@
 
 #define DEFAULT_NAME "Neat VNC"
 #define SECURITY_TYPES_MAX 3
-#define RSA_AES_SERVER_KEY_LENGTH 256
+#define APPLE_DH_SERVER_KEY_LENGTH 256
 
 #define UDIV_UP(a, b) (((a) + (b) - 1) / (b))
 
@@ -409,11 +409,11 @@ static int apple_dh_send_public_key(struct nvnc_client* client)
 		crypto_derive_public_key(client->apple_dh_secret);
 	assert(pub);
 
-	uint8_t mod[RSA_AES_SERVER_KEY_LENGTH] = {};
+	uint8_t mod[APPLE_DH_SERVER_KEY_LENGTH] = {};
 	int mod_len = crypto_key_p(pub, mod, sizeof(mod));
 	assert(mod_len == sizeof(mod));
 
-	uint8_t q[RSA_AES_SERVER_KEY_LENGTH] = {};
+	uint8_t q[APPLE_DH_SERVER_KEY_LENGTH] = {};
 	int q_len = crypto_key_q(pub, q, sizeof(q));
 	assert(q_len == sizeof(q));
 
@@ -437,7 +437,7 @@ static int on_apple_dh_response(struct nvnc_client* client)
 	struct rfb_apple_dh_client_msg* msg =
 	        (void*)(client->msg_buffer + client->buffer_index);
 
-	uint8_t p[RSA_AES_SERVER_KEY_LENGTH];
+	uint8_t p[APPLE_DH_SERVER_KEY_LENGTH];
 	int key_len = crypto_key_p(client->apple_dh_secret, p, sizeof(p));
 	assert(key_len == sizeof(p));
 
@@ -454,7 +454,7 @@ static int on_apple_dh_response(struct nvnc_client* client)
 		crypto_derive_shared_secret(client->apple_dh_secret, remote_key);
 	assert(shared_secret);
 
-	uint8_t shared_buf[RSA_AES_SERVER_KEY_LENGTH];
+	uint8_t shared_buf[APPLE_DH_SERVER_KEY_LENGTH];
 	crypto_key_q(shared_secret, shared_buf, sizeof(shared_buf));
 	crypto_key_del(shared_secret);
 
@@ -504,22 +504,22 @@ static int rsa_aes_send_public_key(struct nvnc_client* client)
 	}
 	assert(server->rsa_pub && server->rsa_priv);
 
-	char buffer[sizeof(struct rfb_rsa_aes_pub_key_msg) +
-		RSA_AES_SERVER_KEY_LENGTH * 2] = {};
+	size_t key_len = crypto_rsa_pub_key_length(server->rsa_pub);
+	size_t buf_len = sizeof(struct rfb_rsa_aes_pub_key_msg) + key_len * 2;
+
+	char* buffer = calloc(1, buf_len);
+	assert(buffer);
 	struct rfb_rsa_aes_pub_key_msg* msg =
 		(struct rfb_rsa_aes_pub_key_msg*)buffer;
 
 	uint8_t* modulus = msg->modulus_and_exponent;
-	uint8_t* exponent = msg->modulus_and_exponent +
-		RSA_AES_SERVER_KEY_LENGTH;
+	uint8_t* exponent = msg->modulus_and_exponent + key_len;
 
-	msg->length = htonl(RSA_AES_SERVER_KEY_LENGTH * 8);
-	crypto_rsa_pub_key_modulus(server->rsa_pub, modulus,
-			RSA_AES_SERVER_KEY_LENGTH);
-	crypto_rsa_pub_key_exponent(server->rsa_pub, exponent,
-			RSA_AES_SERVER_KEY_LENGTH);
+	msg->length = htonl(key_len * 8);
+	crypto_rsa_pub_key_modulus(server->rsa_pub, modulus, key_len);
+	crypto_rsa_pub_key_exponent(server->rsa_pub, exponent, key_len);
 
-	stream_write(client->net_stream, buffer, sizeof(buffer), NULL, NULL);
+	stream_send(client->net_stream, rcbuf_new(buffer, buf_len), NULL, NULL);
 	return 0;
 }
 
@@ -533,8 +533,8 @@ static int rsa_aes_send_challenge(struct nvnc_client* client,
 		(struct rfb_rsa_aes_challenge_msg*)buffer;
 
 	ssize_t len = crypto_rsa_encrypt(pub, msg->challenge,
-			RSA_AES_SERVER_KEY_LENGTH, client->rsa.challenge,
-			client->rsa.challenge_len);
+			crypto_rsa_pub_key_length(client->rsa.pub),
+			client->rsa.challenge, client->rsa.challenge_len);
 	msg->length = htons(len);
 
 	nvnc_trace("Challenge length is %zd", len);
@@ -638,12 +638,14 @@ static int on_rsa_aes_challenge(struct nvnc_client* client)
 	stream_upgrade_to_rsa_eas(client->net_stream, client->rsa.cipher_type,
 			server_session_key, client_session_key);
 
-	uint8_t server_modulus[RSA_AES_SERVER_KEY_LENGTH];
-	uint8_t server_exponent[RSA_AES_SERVER_KEY_LENGTH];
+	size_t server_key_len = crypto_rsa_pub_key_length(server->rsa_pub);
+	uint8_t* server_modulus = malloc(server_key_len * 2);
+	uint8_t* server_exponent = server_modulus + server_key_len;
+
 	crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus,
-			RSA_AES_SERVER_KEY_LENGTH);
+			server_key_len);
 	crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent,
-			RSA_AES_SERVER_KEY_LENGTH);
+			server_key_len);
 
 	size_t client_key_len = crypto_rsa_pub_key_length(client->rsa.pub);
 	uint8_t* client_modulus = malloc(client_key_len * 2);
@@ -654,21 +656,22 @@ static int on_rsa_aes_challenge(struct nvnc_client* client)
 	crypto_rsa_pub_key_exponent(client->rsa.pub, client_exponent,
 			client_key_len);
 
-	uint32_t server_key_len_be = htonl(RSA_AES_SERVER_KEY_LENGTH * 8);
+	uint32_t server_key_len_be = htonl(server_key_len * 8);
 	uint32_t client_key_len_be = htonl(client_key_len * 8);
 
 	uint8_t server_hash[32] = {};
 	crypto_hash_many(server_hash, client_rsa_aes_hash_len(client),
 			client->rsa.hash_type, (const struct crypto_data_entry[]) {
 		{ (uint8_t*)&server_key_len_be, 4 },
-		{ server_modulus, RSA_AES_SERVER_KEY_LENGTH },
-		{ server_exponent, RSA_AES_SERVER_KEY_LENGTH },
+		{ server_modulus, server_key_len },
+		{ server_exponent, server_key_len },
 		{ (uint8_t*)&client_key_len_be, 4 },
 		{ client_modulus, client_key_len },
 		{ client_exponent, client_key_len },
 		{}
 	});
 
+	free(server_modulus);
 	free(client_modulus);
 
 	stream_write(client->net_stream, server_hash,
@@ -688,12 +691,13 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client)
 
 	struct nvnc* server = client->server;
 
-	uint8_t server_modulus[RSA_AES_SERVER_KEY_LENGTH];
-	uint8_t server_exponent[RSA_AES_SERVER_KEY_LENGTH];
+	size_t server_key_len = crypto_rsa_pub_key_length(server->rsa_pub);
+	uint8_t* server_modulus = malloc(server_key_len * 2);
+	uint8_t* server_exponent = server_modulus + server_key_len;
 	crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus,
-			RSA_AES_SERVER_KEY_LENGTH);
+			server_key_len);
 	crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent,
-			RSA_AES_SERVER_KEY_LENGTH);
+			server_key_len);
 
 	size_t client_key_len = crypto_rsa_pub_key_length(client->rsa.pub);
 	uint8_t* client_modulus = malloc(client_key_len * 2);
@@ -704,7 +708,7 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client)
 	crypto_rsa_pub_key_exponent(client->rsa.pub, client_exponent,
 			client_key_len);
 
-	uint32_t server_key_len_be = htonl(RSA_AES_SERVER_KEY_LENGTH * 8);
+	uint32_t server_key_len_be = htonl(server_key_len * 8);
 	uint32_t client_key_len_be = htonl(client_key_len * 8);
 
 	uint8_t client_hash[32] = {};
@@ -714,12 +718,13 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client)
 		{ client_modulus, client_key_len },
 		{ client_exponent, client_key_len },
 		{ (uint8_t*)&server_key_len_be, 4 },
-		{ server_modulus, RSA_AES_SERVER_KEY_LENGTH },
-		{ server_exponent, RSA_AES_SERVER_KEY_LENGTH },
+		{ server_modulus, server_key_len },
+		{ server_exponent, server_key_len },
 		{}
 	});
 
 	free(client_modulus);
+	free(server_modulus);
 
 	if (memcmp(msg, client_hash, client_rsa_aes_hash_len(client)) != 0) {
 		nvnc_log(NVNC_LOG_INFO, "Client hash mismatch");