diff --git a/src/chat.h b/src/chat.h
deleted file mode 100644
index 4dedced..0000000
--- a/src/chat.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-#include "tlibc/errors.h"
-
-Result(void) client_run();
-Result(void) server_run(cstr server_endpoint_str);
diff --git a/src/client.c b/src/client.c
deleted file mode 100644
index c144c94..0000000
--- a/src/client.c
+++ /dev/null
@@ -1,209 +0,0 @@
-#include "chat.h"
-#include <readline/readline.h>
-#include <readline/history.h>
-#include "term.h"
-#include "network/socket.h"
-#include "cryptography/cryptography.h"
-#include "tlibc/string/StringBuilder.h"
-
-static const str greeting_art = STR(
-    "   ^,,^                           ╱|\n"
-    "  ( •·•)   Meum!                (o.o`7\n"
-    "  / ` |                 Meum...  |`˜ \\\n"
-    "\\(_,J J                          L l`,)/\n"
-);
-    
-static const str farewell_art = STR(
-    "   ^,,^                           ╱|\n"
-    "  ( -.-)                        (>,<`7\n"
-    "  / ` |        Goodbye!          |`˜ \\\n"
-    "\\(_,J J                          L l`,)/\n"
-);
-
-static Result(void) commandExec(str command, bool* stop);
-
-typedef struct ClientCredential {
-    str username;
-    u8 passhash_lvl2[password_hash_size];
-    EncryptorAES aes_enc;
-    DecryptorAES aes_dec;
-    EncryptorRSA rsa_enc;
-    DecryptorRSA rsa_dec;
-} ClientCredential;
-
-typedef struct ServerConnection {
-    EndpointIPv4 server_end;
-    Socket system_socket;
-    Socket content_socket;
-    EncryptorRSA rsa_enc;
-    EncryptorAES session_aes_enc;
-    DecryptorAES session_aes_dec;
-} ServerConnection;
-
-Result(ServerConnection*) connectToServer(EndpointIPv4 server_end, str server_key);
-
-Result(void) client_run() {
-    Deferral(32);
-    if(!term_init()){
-        Return RESULT_ERROR("can't init terminal", false);
-    }
-    using_history();
-
-    fputs(greeting_art.data, stdout);
-
-    char* command_input_prev = NULL;
-    char* command_input_raw = NULL;
-    Defer(rl_free(command_input_prev));
-    str command_input = str_null;
-    bool stop = false;
-    while((command_input_raw = readline("> ")) && !stop){
-        rl_free(command_input_prev);
-        command_input_prev = command_input_raw;
-        command_input = str_from_cstr(command_input_raw);
-        str_trim(&command_input, true);
-        if(command_input.size == 0)
-            continue;
-        
-        add_history(command_input.data);
-        Result(void) com_result = commandExec(command_input, &stop);
-        if(com_result.error){
-            str e_str = Error_toStr(com_result.error);
-            printfe("%s\n", e_str.data);
-            free(e_str.data);
-            Error_free(com_result.error);
-        }
-    }
-
-    Return RESULT_VOID;
-}
-
-#define is_alias(LITERAL) str_equals(command, STR(LITERAL))
-
-static ClientCredential* client_credential = NULL;
-
-static Result(void) commandExec(str command, bool* stop){
-    Deferral(64);
-    char answer_buf[512];
-    const u32 answer_buf_size = sizeof(answer_buf);
-    if(is_alias("q") || is_alias("quit") || is_alias("exit")){
-        fputs(farewell_art.data, stdout);
-        *stop = true;
-    }
-    else if(is_alias("clear")){
-        term_clear();
-    }
-    else if(is_alias("h") || is_alias("help")){
-        puts(
-            "COMMANDS:\n"
-            "q, quit, exit                  Close the program.\n"
-            "clear                          Clear the screen.\n"
-            "j, join                        Join a server.\n"
-            "c, connect                     Connect to a server you joined.\n"
-        );
-    }
-    else if (is_alias("j") || is_alias("join")){
-        puts("Enter server address (ip:port): ");
-        fgets(answer_buf, answer_buf_size, stdin);
-        EndpointIPv4 new_server_end;
-        try_void(EndpointIPv4_parse(answer_buf, &new_server_end));
-        puts("Enter server key (): ");
-        fgets(answer_buf, answer_buf_size, stdin);
-        str new_server_key = str_from_cstr(answer_buf);
-        try(ServerConnection* conn, p, connectToServer(new_server_end, new_server_key));
-    }
-    else if(is_alias("c") || is_alias("connect")){
-        // TODO: read saved servers from database
-    }
-    else {
-        Return RESULT_ERROR_FMT("unknown kommand: '%s'\n"
-            "Use 'h' to see list of avaliable commands\n",
-            command.data);
-    }
-
-    Return RESULT_VOID;
-}
-
-void ClientCredential_free(ClientCredential* cred){
-    if(cred == NULL)
-        return;
-    free(cred->username.data);
-    free(cred);
-}
-
-#define __passhash_lvl_iter 1e5
-
-Result(ClientCredential*) ClientCredential_create(str username, str password){
-    Deferral(32);
-    ClientCredential* cred = (ClientCredential*)malloc(sizeof(ClientCredential));
-    memset(cred, 0, sizeof(ClientCredential));
-    bool success = false;
-    Defer(
-        if(!success)
-            ClientCredential_free(cred);
-    );
-
-    cred->username = str_copy(username);
-    
-    // concat password and username
-    StringBuilder sb = StringBuilder_alloc(username.size + password.size + 1);
-    Defer(StringBuilder_destroy(&sb));
-    StringBuilder_append_str(&sb, password);
-    StringBuilder_append_str(&sb, username);
-
-    // lvl 1 hash - is being used to generate rsa keys
-    u8 passhash_lvl1[password_hash_size];
-    hash_password(StringBuilder_getStr(&sb), passhash_lvl1, __passhash_lvl_iter);
-    // lvl 2 hash - is being used to authorize client on server
-    str _passhash_lvl1_str = str_construct((void*)passhash_lvl1, password_hash_size, false);
-    hash_password(_passhash_lvl1_str, cred->passhash_lvl2, __passhash_lvl_iter);
-    
-        
-    success = true;
-    return RESULT_VALUE(p, cred);
-} 
-
-void ServerConnection_close(ServerConnection* conn){
-    if(conn == NULL)
-        return;
-    socket_close(conn->system_socket);
-    socket_close(conn->content_socket);
-    free(conn);
-}
-
-Result(ServerConnection*) connectToServer(EndpointIPv4 server_end, str server_key){
-    Deferral(64);
-    if(client_credential == NULL){
-
-    }
-
-    str end_str = EndpointIPv4_toStr(server_end);
-    Defer(free(end_str.data));
-    if(EndpointIPv4_is_invalid(server_end)){
-        Return RESULT_ERROR_FMT("endpoint is invalid: %s", end_str.data);
-    }
-    
-    ServerConnection* conn = (ServerConnection*)malloc(sizeof(ServerConnection));
-    memset(conn, 0, sizeof(ServerConnection));
-    bool success = false;
-    Defer(
-        if(!success)
-            ServerConnection_close(conn);
-    );
-    
-    printf("connecting to server %s\n", end_str.data);
-    try(conn->system_socket, i, socket_open_TCP());
-    try_void(socket_connect(conn->system_socket, server_end));
-
-    // ask user name and password
-    // calculate key pair from password hash
-    // send client public key to server
-    // request server info
-    // show server info
-    // save server info to user's db
-    // hash password more times
-    // request log in
-    // if not registered, request registration and then log in
-
-    success = true;
-    Return RESULT_VALUE(p, conn);
-}
diff --git a/src/client/ClientCredential.c b/src/client/ClientCredential.c
new file mode 100644
index 0000000..8cb7330
--- /dev/null
+++ b/src/client/ClientCredential.c
@@ -0,0 +1,74 @@
+#include "client.h"
+#include "tlibc/string/StringBuilder.h"
+
+void ClientCredential_free(ClientCredential* cred){
+    if(cred == NULL)
+        return;
+    free(cred->username.data);
+    free(cred->aes_key.data);
+    free(cred->token.data);
+    RSA_destroyPrivateKey(&cred->sk);
+    RSA_destroyPublicKey(&cred->pk);
+    free(cred);
+}
+
+#define __passhash_lvl_iter 1e5
+
+Result(ClientCredential*) ClientCredential_create(str username, str password){
+    Deferral(32);
+    ClientCredential* cred = (ClientCredential*)malloc(sizeof(ClientCredential));
+    memset(cred, 0, sizeof(ClientCredential));
+    bool success = false;
+    Defer(
+        if(!success)
+            free(cred);
+    );
+
+    cred->username = str_copy(username);
+    Defer(
+        if(!success)
+            free(cred->username.data);
+    );
+
+    // concat password and username
+    StringBuilder sb = StringBuilder_alloc(username.size + password.size + 1);
+    Defer(StringBuilder_destroy(&sb));
+    StringBuilder_append_str(&sb, password);
+    StringBuilder_append_str(&sb, username);
+    Array(u8) password_and_username = str_castTo_Array(StringBuilder_getStr(&sb));
+    // lvl 1 hash - is used to generate RSA keys
+    Array(u8) passhash_lvl1 = Array_alloc(u8, password_hash_size);
+    cred->aes_key = Array_alloc(u8, password_hash_size);
+    cred->token = Array_alloc(u8, password_hash_size);
+    Defer(
+        free(passhash_lvl1.data);
+        if(!success){
+            free(cred->aes_key.data);
+            free(cred->token.data);
+        }
+    );
+    hash_password(password_and_username, passhash_lvl1.data, __passhash_lvl_iter);
+    // lvl 2 hash - is used as AES key
+    hash_password(passhash_lvl1, cred->aes_key.data, __passhash_lvl_iter);
+    // lvl 3 hash - is used to authorize client on server
+    hash_password(cred->aes_key, cred->token.data, __passhash_lvl_iter);
+    
+    // generate client rsa keys from password hash
+    br_hmac_drbg_context passhash_based_rng = { .vtable = &br_hmac_drbg_vtable };
+    br_hmac_drbg_init(&passhash_based_rng, &br_sha256_vtable, passhash_lvl1.data, password_hash_size);
+    try_void(RSA_generateKeyPair(4096, &cred->sk, &cred->pk, &passhash_based_rng.vtable));
+    Defer(
+        if(!success){
+            RSA_destroyPrivateKey(&cred->sk);
+            RSA_destroyPublicKey(&cred->pk);
+        }
+    );
+
+    DecryptorRSA_construct(&cred->rsa_dec, &cred->sk);
+    EncryptorRSA_construct(&cred->rsa_enc, &cred->pk);
+    DecryptorAES_construct(&cred->aes_dec, cred->aes_key);
+    EncryptorAES_construct(&cred->aes_enc, cred->aes_key);
+
+    success = true;
+    Return RESULT_VALUE(p, cred);
+}
diff --git a/src/client/ServerConnection.c b/src/client/ServerConnection.c
new file mode 100644
index 0000000..c592671
--- /dev/null
+++ b/src/client/ServerConnection.c
@@ -0,0 +1,44 @@
+#include "client.h"
+
+void ServerConnection_close(ServerConnection* conn){
+    if(conn == NULL)
+        return;
+    socket_close(conn->system_socket);
+    socket_close(conn->content_socket);
+    free(conn);
+}
+
+Result(ServerConnection*) ServerConnection_open(ClientCredential* client_credential, EndpointIPv4 server_end, str server_key){
+    Deferral(64);
+
+    str end_str = EndpointIPv4_toStr(server_end);
+    Defer(free(end_str.data));
+    if(EndpointIPv4_is_invalid(server_end)){
+        Return RESULT_ERROR_FMT("endpoint is invalid: %s", end_str.data);
+    }
+    
+    ServerConnection* conn = (ServerConnection*)malloc(sizeof(ServerConnection));
+    memset(conn, 0, sizeof(ServerConnection));
+    bool success = false;
+    Defer(
+        if(!success)
+            ServerConnection_close(conn);
+    );
+    
+    printf("connecting to server %s\n", end_str.data);
+    try(conn->system_socket, i, socket_open_TCP());
+    try_void(socket_connect(conn->system_socket, server_end));
+
+    // ask user name and password
+    // calculate key pair from password hash
+    // send client public key to server
+    // request server info
+    // show server info
+    // save server info to user's db
+    // hash password more times
+    // request log in
+    // if not registered, request registration and then log in
+
+    success = true;
+    Return RESULT_VALUE(p, conn);
+}
diff --git a/src/client/client.c b/src/client/client.c
new file mode 100644
index 0000000..1c8edf3
--- /dev/null
+++ b/src/client/client.c
@@ -0,0 +1,118 @@
+// readline.h doesn't include stdio.h 
+// This bug is older than me)))
+#include "client.h"
+#include <stdio.h>
+#include <readline/readline.h>
+#include <readline/history.h>
+#include "term.h"
+
+static const str greeting_art = STR(
+    "   ^,,^                           ╱|\n"
+    "  ( •·•)   Meum!                (o.o`7\n"
+    "  / ` |                 Meum...  |`˜ \\\n"
+    "\\(_,J J                          L l`,)/\n"
+);
+    
+static const str farewell_art = STR(
+    "   ^,,^                           ╱|\n"
+    "  ( -.-)                        (>,<`7\n"
+    "  / ` |        Goodbye!          |`˜ \\\n"
+    "\\(_,J J                          L l`,)/\n"
+);
+
+static ClientCredential* client_credential = NULL;
+
+static Result(void) commandExec(str command, bool* stop);
+
+static Result(void) askUserNameAndPassword(ClientCredential** cred){
+    Deferral(8);
+    char username[1024];
+    char password[1024];
+    scanf("username: %s", username);
+    scanf("password: %s", password);
+    try(*cred, p, ClientCredential_create(str_from_cstr(username), str_from_cstr(password)));
+    Return RESULT_VOID;
+}
+
+Result(void) client_run() {
+    Deferral(32);
+    if(!term_init()){
+        Return RESULT_ERROR("can't init terminal", false);
+    }
+    using_history();
+
+    fputs(greeting_art.data, stdout);
+    try_void(askUserNameAndPassword(&client_credential));
+
+    char* command_input_prev = NULL;
+    char* command_input_raw = NULL;
+    Defer(rl_free(command_input_prev));
+    str command_input = str_null;
+    bool stop = false;
+    while((command_input_raw = readline("> ")) && !stop){
+        rl_free(command_input_prev);
+        command_input_prev = command_input_raw;
+        command_input = str_from_cstr(command_input_raw);
+        str_trim(&command_input, true);
+        if(command_input.size == 0)
+            continue;
+        
+        add_history(command_input.data);
+        Result(void) com_result = commandExec(command_input, &stop);
+        if(com_result.error){
+            str e_str = Error_toStr(com_result.error);
+            printfe("%s\n", e_str.data);
+            free(e_str.data);
+            Error_free(com_result.error);
+        }
+    }
+
+    ClientCredential_free(client_credential);
+    Return RESULT_VOID;
+}
+
+#define is_alias(LITERAL) str_equals(command, STR(LITERAL))
+
+static Result(void) commandExec(str command, bool* stop){
+    Deferral(64);
+    char answer_buf[512];
+    const u32 answer_buf_size = sizeof(answer_buf);
+    if(is_alias("q") || is_alias("quit") || is_alias("exit")){
+        fputs(farewell_art.data, stdout);
+        *stop = true;
+    }
+    else if(is_alias("clear")){
+        term_clear();
+    }
+    else if(is_alias("h") || is_alias("help")){
+        puts(
+            "COMMANDS:\n"
+            "q, quit, exit                  Close the program.\n"
+            "clear                          Clear the screen.\n"
+            "j, join                        Join a server.\n"
+            "c, connect                     Connect to a server you joined.\n"
+        );
+    }
+    else if (is_alias("j") || is_alias("join")){
+        puts("Enter server address (ip:port): ");
+        fgets(answer_buf, answer_buf_size, stdin);
+        EndpointIPv4 new_server_end;
+        try_void(EndpointIPv4_parse(answer_buf, &new_server_end));
+        puts("Enter server key (): ");
+        fgets(answer_buf, answer_buf_size, stdin);
+        str new_server_key = str_from_cstr(answer_buf);
+        try(ServerConnection* conn, p, ServerConnection_open(client_credential, new_server_end, new_server_key));
+        // TODO: close server connection somewhere
+    }
+    else if(is_alias("c") || is_alias("connect")){
+        // TODO: read saved servers from database
+    }
+    else {
+        Return RESULT_ERROR_FMT("unknown kommand: '%s'\n"
+            "Use 'h' to see list of avaliable commands\n",
+            command.data);
+    }
+
+    Return RESULT_VOID;
+}
+
diff --git a/src/client/client.h b/src/client/client.h
new file mode 100644
index 0000000..bd93a06
--- /dev/null
+++ b/src/client/client.h
@@ -0,0 +1,32 @@
+#pragma once
+#include "network/socket.h"
+#include "cryptography/cryptography.h"
+
+Result(void) client_run();
+
+typedef struct ClientCredential {
+    str username;
+    Array(u8) aes_key;
+    Array(u8) token;
+    br_rsa_private_key sk;
+    br_rsa_public_key pk;
+    EncryptorRSA rsa_enc;
+    DecryptorRSA rsa_dec;
+    EncryptorAES aes_enc;
+    DecryptorAES aes_dec;
+} ClientCredential;
+
+Result(ClientCredential*) ClientCredential_create(str username, str password);
+void ClientCredential_free(ClientCredential* cred);
+
+typedef struct ServerConnection {
+    EndpointIPv4 server_end;
+    Socket system_socket;
+    Socket content_socket;
+    EncryptorRSA rsa_enc;
+    EncryptorAES session_aes_enc;
+    DecryptorAES session_aes_dec;
+} ServerConnection;
+
+Result(ServerConnection*) ServerConnection_open(ClientCredential* client_credential, EndpointIPv4 server_end, str server_key);
+void ServerConnection_close(ServerConnection* conn);
\ No newline at end of file
diff --git a/src/cryptography/AES.c b/src/cryptography/AES.c
index c6b7195..9e17890 100755
--- a/src/cryptography/AES.c
+++ b/src/cryptography/AES.c
@@ -3,11 +3,12 @@
 
 //TODO: use AES CTR encryption instead of my own padding algorithm
 
-void EncryptorAES_init(EncryptorAES* ptr, Array(u8) key){
+void EncryptorAES_construct(EncryptorAES* ptr, Array(u8) key){
     assert(key.size == 16 || key.size == 24 || key.size == 32);
     
     br_aes_ct64_cbcenc_init(&ptr->enc_ctx, key.data, key.size);
-    rng_init_sha256_seedFromTime(&br_hmac_drbg_vtable, &ptr->rng_ctx.vtable);
+    ptr->rng_ctx.vtable = &br_hmac_drbg_vtable;
+    rng_init_sha256_seedFromTime(&ptr->rng_ctx.vtable);
 
     memset(ptr->buf, 0, __AES_BUFFER_SIZE);
     memset(ptr->iv, 0, sizeof(ptr->iv));
@@ -49,7 +50,7 @@ void EncryptorAES_encrypt(EncryptorAES* ptr, Array(u8) src, Array(u8) dst){
 }
 
 
-void DecryptorAES_init(DecryptorAES* ptr, Array(u8) key){
+void DecryptorAES_construct(DecryptorAES* ptr, Array(u8) key){
     assert(key.size == 16 || key.size == 24 || key.size == 32);
     
     br_aes_ct64_cbcdec_init(&ptr->dec_ctx, key.data, key.size);
diff --git a/src/cryptography/RSA.c b/src/cryptography/RSA.c
index dc92e9a..9ec72d7 100644
--- a/src/cryptography/RSA.c
+++ b/src/cryptography/RSA.c
@@ -6,14 +6,32 @@
 // https://crypto.stackexchange.com/questions/3110/impacts-of-not-using-rsa-exponent-of-65537
 #define DEFAULT_PUBLIC_EXPONENT 65537
 
-bool RSA_generateKeyPair(u32 key_size, br_rsa_private_key* sk, br_rsa_public_key* pk){
-    br_hmac_drbg_context rng_ctx;
-    const br_prng_class** rng_class_ptr = &rng_ctx.vtable;
-    rng_init_sha256_seedFromTime(&br_hmac_drbg_vtable, rng_class_ptr);
+Result(void) RSA_generateKeyPair(u32 key_size,
+    br_rsa_private_key* sk, br_rsa_public_key* pk,
+    const br_prng_class** rng_vtable_ptr)
+{
+    Deferral(16);
+    bool success = false;
+    rng_init_sha256_seedFromTime(rng_vtable_ptr);
+    
     void* sk_buf = malloc(BR_RSA_KBUF_PRIV_SIZE(key_size));
+    Defer(
+        if(!success)
+            free(sk_buf)
+    );
+    
     void* pk_buf = malloc(BR_RSA_KBUF_PUB_SIZE(key_size));
-    u32 r = br_rsa_i31_keygen(rng_class_ptr, sk, sk_buf, pk, pk_buf, key_size, DEFAULT_PUBLIC_EXPONENT);
-    return r;
+    Defer(
+        if(!success)
+            free(pk_buf)
+    );
+    
+    success = br_rsa_i31_keygen(rng_vtable_ptr, sk, sk_buf, pk, pk_buf, key_size, DEFAULT_PUBLIC_EXPONENT);
+    if(!success){
+        Return RESULT_ERROR("br_rsa_i31_keygen() failed", false);
+    }
+
+    Return RESULT_VOID;
 }
 
 Result(void) RSA_computePublicKey(const br_rsa_private_key* sk, br_rsa_public_key* pk){
@@ -162,7 +180,8 @@ Result(void) RSA_parsePrivateKey_DER(Array(u8) _src, br_rsa_private_key* sk){
 
 void EncryptorRSA_construct(EncryptorRSA* ptr, const br_rsa_public_key* pk){
     ptr->pk = pk;
-    rng_init_sha256_seedFromTime(&br_hmac_drbg_vtable, &ptr->rng.vtable);
+    ptr->rng.vtable = &br_hmac_drbg_vtable;
+    rng_init_sha256_seedFromTime(&ptr->rng.vtable);
 }
 
 void EncryptorRSA_encrypt(EncryptorRSA* ptr, Array(u8) src, Array(u8) dst, u32* encrypted_size){
diff --git a/src/cryptography/cryptography.h b/src/cryptography/cryptography.h
index 6068a34..9e53fd1 100755
--- a/src/cryptography/cryptography.h
+++ b/src/cryptography/cryptography.h
@@ -15,7 +15,7 @@
 /// @param password some byte array 
 /// @param out_buffer u8[password_hash_size]
 /// @param iterations number of iterations
-void hash_password(str password, u8* out_buffer, i32 iterations);
+void hash_password(Array(u8) password, u8* out_buffer, i32 iterations);
 #define password_hash_size 32
 
 
@@ -24,14 +24,13 @@ void hash_password(str password, u8* out_buffer, i32 iterations);
 //////////////////////////////////////////////////////////////////////////////
 
 /// @brief Initialize prng context with sha256 hashing algorithm and seed from CLOCK_REALTIME.
-/// @param rng_class pointer to static vtable variable
-/// @param rng_ctx pointer to vtable field in prng context
+/// @param rng_vtable_ptr pointer to vtable field in prng context. The field must be initialized.
 /// EXAMPLE:
 /// ```
-/// br_hmac_drbg_context rng_ctx;
-/// rng_init_sha256_seedFromTime(&br_hmac_drbg_vtable, &rng_ctx.vtable);
+/// br_hmac_drbg_context rng_ctx = { .vtable = &br_hmac_drbg_vtable };
+/// rng_init_sha256_seedFromTime(&rng_ctx.vtable);
 /// ```
-void rng_init_sha256_seedFromTime(const br_prng_class* rng_class, const br_prng_class** rng_ctx);
+void rng_init_sha256_seedFromTime(const br_prng_class** rng_vtable_ptr);
 
 
 //////////////////////////////////////////////////////////////////////////////
@@ -57,7 +56,7 @@ typedef struct EncryptorAES {
 } EncryptorAES;
 
 /// @param key Array<u8, 16 | 24 | 32>
-void EncryptorAES_init(EncryptorAES* ptr, Array(u8) key);
+void EncryptorAES_construct(EncryptorAES* ptr, Array(u8) key);
 
 /// @brief Encrypts `src` and writes output to `dst`.
 /// @param src array of any size
@@ -74,7 +73,7 @@ typedef struct DecryptorAES {
 } DecryptorAES;
 
 /// @param key Array<u8, 16 | 24 | 32>
-void DecryptorAES_init(DecryptorAES* ptr, Array(u8) key);
+void DecryptorAES_construct(DecryptorAES* ptr, Array(u8) key);
 
 /// @brief Decrypts `src` and writes output to `dst`.
 /// @param src array of any size
@@ -91,8 +90,10 @@ void DecryptorAES_decrypt(DecryptorAES* ptr, Array(u8) src, Array(u8) dst, u32*
 /// @param key_size size of public key in bits (2048/3072/4096)
 /// @param sk key for decryption
 /// @param pk key for encryption
-/// @return true on success
-bool RSA_generateKeyPair(u32 key_size, br_rsa_private_key* sk, br_rsa_public_key* pk);
+/// @param rng_vtable_ptr pointer to vtable field in prng context. The context must be initialized
+Result(void) RSA_generateKeyPair(u32 key_size, 
+    br_rsa_private_key* sk, br_rsa_public_key* pk,
+    const br_prng_class** rng_vtable_ptr);
 
 static inline void RSA_destroyPrivateKey(br_rsa_private_key* sk){
     free(sk->p);
diff --git a/src/cryptography/hash.c b/src/cryptography/hash.c
index ac69578..8ce6879 100755
--- a/src/cryptography/hash.c
+++ b/src/cryptography/hash.c
@@ -2,7 +2,7 @@
 #include "bearssl_hash.h"
 #include "assert.h"
 
-void hash_password(str password, u8* out_buffer, i32 iterations){
+void hash_password(Array(u8) password, u8* out_buffer, i32 iterations){
     assert(password_hash_size == br_sha256_SIZE);;
     memset(out_buffer, 0, br_sha256_SIZE);
     br_sha256_context sha256_ctx;
diff --git a/src/cryptography/rng.c b/src/cryptography/rng.c
index 1659c7e..7fe2031 100644
--- a/src/cryptography/rng.c
+++ b/src/cryptography/rng.c
@@ -1,7 +1,8 @@
 #include "cryptography.h"
 #include "tlibc/time.h"
 
-void rng_init_sha256_seedFromTime(const br_prng_class* rng_class, const br_prng_class** rng_ctx){
+void rng_init_sha256_seedFromTime(const br_prng_class** rng_vtable_ptr){
     nsec_t time_now = getTimeNsec();
-    rng_class->init(rng_ctx, &br_sha256_vtable, &time_now, sizeof(time_now));
+    const br_prng_class* rng_vtable = *rng_vtable_ptr;
+    rng_vtable->init(rng_vtable_ptr, &br_sha256_vtable, &time_now, sizeof(time_now));
 }
diff --git a/src/main.c b/src/main.c
index ccb8e75..7642b9d 100755
--- a/src/main.c
+++ b/src/main.c
@@ -1,6 +1,6 @@
 #include "network/network.h"
-#include "chat.h"
-#include "cryptography/cryptography.h"
+#include "client/client.h"
+#include "server/server.h"
 
 typedef enum ProgramMode {
     Client,
diff --git a/src/network/endpoint.h b/src/network/endpoint.h
index 075e2e4..8f2d243 100755
--- a/src/network/endpoint.h
+++ b/src/network/endpoint.h
@@ -1,6 +1,7 @@
 #pragma once
 #include "tlibc/std.h"
 #include "tlibc/string/str.h"
+#include "tlibc/errors.h"
 
 #define port_INVALID ((u16)~0)
 #define port_is_invalid(PORT) (PORT == port_INVALID)
diff --git a/src/server.c b/src/server/server.c
similarity index 95%
rename from src/server.c
rename to src/server/server.c
index 4b6f0d4..6e2ee9f 100644
--- a/src/server.c
+++ b/src/server/server.c
@@ -1,5 +1,4 @@
-#include "chat.h"
-#include "network/socket.h"
+#include "server.h"
 #include "db/idb.h"
 #include <pthread.h>
 
diff --git a/src/server/server.h b/src/server/server.h
new file mode 100644
index 0000000..2428a33
--- /dev/null
+++ b/src/server/server.h
@@ -0,0 +1,5 @@
+#pragma once
+#include "network/socket.h"
+#include "cryptography/cryptography.h"
+
+Result(void) server_run(cstr server_endpoint_str);