diff --git a/7-SGX_Hands-on/src/enclave/enclave.c b/7-SGX_Hands-on/src/enclave/enclave.c
index 7ab26cb..db96ec4 100644
--- a/7-SGX_Hands-on/src/enclave/enclave.c
+++ b/7-SGX_Hands-on/src/enclave/enclave.c
@@ -80,7 +80,7 @@ int get_private_key_size() {
     return SK_SIZE;
 }
 
-sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *public, uint8_t **sealed, uint32_t sealed_size) {
+static sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *public, uint8_t **sealed, uint32_t sealed_size) {
     // invalid parameter handling
     if((private == NULL) || (public == NULL))
         return SGX_ERROR_INVALID_PARAMETER;
@@ -103,7 +103,7 @@ sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *pub
     return sgx_seal_data(PK_SIZE, (const uint8_t *)pk, SK_SIZE, (const uint8_t *)sk, size, (sgx_sealed_data_t *) *sealed);
 }
 
-sgx_status_t unseal_key_pair(const uint8_t *sealed, sgx_ec256_private_t *private, sgx_ec256_public_t *public) {
+static sgx_status_t unseal_key_pair(const uint8_t *sealed, sgx_ec256_private_t *private, sgx_ec256_public_t *public) {
     // invalid parameter handling
     if(sealed == NULL) {
         return SGX_ERROR_INVALID_PARAMETER;
@@ -161,15 +161,62 @@ sgx_status_t get_public_key(const uint8_t *sealed, uint32_t sealed_size, uint8_t
     return status;
 }
 
-sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sealed, uint32_t sealed_size, uint8_t *signature, uint32_t signature_size) {
+static sgx_status_t verify_signature(const uint8_t *data, const uint32_t data_size, const sgx_ec256_public_t *public, const sgx_ec256_signature_t* ecc_signature) {
+    // invalid parameter handling
+    if((data == NULL) || (data_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if(public == NULL) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if(ecc_signature == NULL) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // declare needed structure
+    sgx_ecc_state_handle_t ecc_handle;
+
+    // open ecc handle
+    sgx_status_t status;
+    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // verify signature
+    uint8_t result;
+    sgx_status_t verification_status = sgx_ecdsa_verify(data, data_size, public, ecc_signature, &result, ecc_handle);
+
+    // handle failed verification process
+    if(verification_status != SGX_SUCCESS) {
+        result = verification_status;
+    }
+
+    // close context and return valid signature
+    sgx_ecc256_close_context(ecc_handle);
+    return result;
+}
+
+sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sealed, uint32_t sealed_size, const uint8_t *public_key, uint32_t public_key_size, uint8_t *signature, uint32_t signature_size) {
     // invalid parameter handling
     if((data == NULL) || (data_size == 0)) {
         return SGX_ERROR_INVALID_PARAMETER;
     } else if((sealed == NULL) || (sealed_size == 0)) {
         return SGX_ERROR_INVALID_PARAMETER;
+    } else if((public_key == NULL) || (public_key_size != PK_SIZE)) {
+        return SGX_ERROR_INVALID_PARAMETER;
     }
+
+    // verify public key
+    for(size_t i = 0; i < sizeof(authorized)/sizeof(authorized[0]); i++) {
+        if(memcmp(public_key, authorized[i].gx, PK_SIZE) != 0) {
+            continue;
+        }
+        goto sign;
+    }
+    return SGX_ERROR_UNEXPECTED;
     
+    sign: ;
+
     // declare need structures
+    sgx_ec256_signature_t ecc_signature;
     sgx_ecc_state_handle_t ecc_handle;
     sgx_ec256_private_t private;
     sgx_ec256_public_t public;
@@ -180,6 +227,13 @@ sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sea
         return status;
     }
 
+    // verify request
+    /*
+    if((status = verify_signature(data, data_size, (const sgx_ec256_public_t *)public_key, (const sgx_ec256_signature_t *)signature)) != SGX_EC_VALID) {
+        sgx_ecc256_close_context(ecc_handle);
+        return status;
+    }*/
+
     // try unseal keypair
     sgx_status_t seal_status;
     if(seal_status = unseal_key_pair(sealed, &private, NULL) != SGX_SUCCESS) {
@@ -190,7 +244,6 @@ sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sea
     }
 
     // create signature
-    sgx_ec256_signature_t ecc_signature;
     if((status = sgx_ecdsa_sign(data, data_size, &private, &ecc_signature, ecc_handle)) != SGX_SUCCESS) {
         sgx_ecc256_close_context(ecc_handle);
         return status;
@@ -226,53 +279,36 @@ sgx_status_t verify_firmware(const uint8_t *data, uint32_t data_size, const uint
         return SGX_ERROR_INVALID_PARAMETER;
     }
 
-    // declare need structures
-    sgx_ec256_signature_t ecc_signature;
-    sgx_ecc_state_handle_t ecc_handle;
+    // declare needed structures
     sgx_ec256_public_t public;
+    sgx_status_t status;
 
     // invalid signature
     if(signature_size > SI_SIZE) {
         return SGX_ERROR_INVALID_PARAMETER;
     }
 
-    // open ecc handle
-    sgx_status_t status;
-    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
-        return status;
-    }
-
-    // copy signature into struct
-    memcpy(ecc_signature.x, signature, SI_SIZE);
-
     // verify signature from staff or enclave
     if(public_key != NULL) {
         // invalid public key
         if(public_key_size != PK_SIZE) {
-            sgx_ecc256_close_context(ecc_handle);
             return SGX_ERROR_INVALID_PARAMETER;
         }
 
+        // verification only with authorized public keys
+        for(size_t i = 0; i < sizeof(authorized)/sizeof(authorized[0]); i++) {
+
+        }
+
         // copy public key into struct
         memcpy(public.gx, public_key, PK_SIZE);
     } else {
         // unseal public key
-        if(unseal_key_pair(sealed, NULL, &public) != SGX_SUCCESS) {
-            sgx_ecc256_close_context(ecc_handle);
-            return SGX_ERROR_UNEXPECTED;
+        if((status = unseal_key_pair(sealed, NULL, &public)) != SGX_SUCCESS) {
+            return status;
         }
     }
 
-    // verify signature
-    uint8_t result;
-    sgx_status_t verification_status = sgx_ecdsa_verify(data, data_size, (const sgx_ec256_public_t *)&public, (const sgx_ec256_signature_t *)&ecc_signature, &result, ecc_handle);
-
-    // handle failed verification process
-    if(verification_status != SGX_SUCCESS) {
-        result = verification_status;
-    }
-
-    // close handle and return result
-    sgx_ecc256_close_context(ecc_handle);
-    return result;
-}
+    // verify signature and return result
+    return verify_signature(data, data_size, &public, (const sgx_ec256_signature_t *)signature);
+}
\ No newline at end of file
diff --git a/Assignment 7 - SGX Hands-on/src/enclave/enclave.c b/Assignment 7 - SGX Hands-on/src/enclave/enclave.c
deleted file mode 100644
index 06a6a36..0000000
--- a/Assignment 7 - SGX Hands-on/src/enclave/enclave.c	
+++ /dev/null
@@ -1,278 +0,0 @@
-/*
- * Copyright (C) 2011-2018 Intel Corporation. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- *   * Redistributions of source code must retain the above copyright
- *     notice, this list of conditions and the following disclaimer.
- *   * Redistributions in binary form must reproduce the above copyright
- *     notice, this list of conditions and the following disclaimer in
- *     the documentation and/or other materials provided with the
- *     distribution.
- *   * Neither the name of Intel Corporation nor the names of its
- *     contributors may be used to endorse or promote products derived
- *     from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-
-#include <stdarg.h>
-#include <stdio.h>      /* vsnprintf */
-#include <string.h>
-#include <stdlib.h>
-
-#include "Enclave.h"
-#include "Enclave_t.h"
-#include <sgx_tseal.h>
-#include <sgx_error.h>
-#include <sgx_tcrypto.h>
-
-#ifndef SK_SIZE
-#define SK_SIZE SGX_ECP256_KEY_SIZE
-#endif
-
-#ifndef PK_SIZE
-#define PK_SIZE 2*SK_SIZE
-#endif
-
-#ifndef SI_SIZE
-#define SI_SIZE 2*SK_SIZE
-#endif
-
-const sgx_ec256_public_t authorized[2] = {
-    {
-        0,
-        0
-    },
-    {
-        0,
-        0
-    }
-};
-
-int get_sealed_size() {
-    return sgx_calc_sealed_data_size(PK_SIZE, SK_SIZE);
-}
-
-int get_signature_size() {
-    return SI_SIZE;
-}
-
-int get_public_key_size() {
-    return PK_SIZE;
-}
-
-int get_private_key_size() {
-    return SK_SIZE;
-}
-
-static sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *public, uint8_t **sealed, uint32_t sealed_size) {
-    // invalid parameter handling
-    if((private == NULL) || (public == NULL))
-        return SGX_ERROR_INVALID_PARAMETER;
-
-    // allocate temporary buffers on stack
-    uint8_t pk[PK_SIZE] = {0};
-    uint8_t sk[SK_SIZE] = {0};
-
-    // copy key pair into buffers
-    memcpy(pk, public->gx, PK_SIZE);
-    memcpy(sk, private->r, SK_SIZE);
-
-    // calculate needed size
-    uint32_t size = get_sealed_size();
-    if(size > sealed_size) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    }
-
-    // seal keypair
-    return sgx_seal_data(PK_SIZE, (const uint8_t *)pk, SK_SIZE, (const uint8_t *)sk, size, (sgx_sealed_data_t *) *sealed);
-}
-
-static sgx_status_t unseal_key_pair(const uint8_t *sealed, sgx_ec256_private_t *private, sgx_ec256_public_t *public) {
-    // invalid parameter handling
-    if(sealed == NULL) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    }
-
-    // allocate temporary buffers on stack
-    uint8_t pk[PK_SIZE] = {0};
-    uint8_t sk[SK_SIZE] = {0};
-    
-    // calculate public_key size and return error for unexpected results
-    uint32_t pk_size = sgx_get_add_mac_txt_len((const sgx_sealed_data_t *)sealed);
-    uint32_t sk_size = sgx_get_encrypt_txt_len((const sgx_sealed_data_t *)sealed);
-    if ((pk_size != PK_SIZE) || (sk_size != SK_SIZE)) {
-        return SGX_ERROR_UNEXPECTED;
-    }
-
-    // unseal ecc key pair
-    sgx_status_t status = sgx_unseal_data((const sgx_sealed_data_t *)sealed, pk, &pk_size, sk, &sk_size);
-    if (status != SGX_SUCCESS) {
-        return status;
-    }
-
-    // copy buffers into key structs
-    if(public != NULL) {
-        memcpy(public->gx, pk, PK_SIZE);
-    }
-    if (private != NULL) {
-        memcpy(private->r, sk, SK_SIZE);
-    }
-
-    // return success
-    return status;
-}
-
-sgx_status_t get_public_key(const uint8_t *sealed, uint32_t sealed_size, uint8_t *gx, uint32_t gx_size, uint8_t *gy, uint32_t gy_size) {
-    // invalid parameter handling
-    if((sealed == NULL) || (sealed_size == 0)) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    }
-
-    // unseal public key
-    sgx_status_t status;
-    sgx_ec256_public_t public;
-    if((status = unseal_key_pair(sealed, NULL, &public)) != SGX_SUCCESS) {
-        return status;
-    }
-
-    // copy public key into return buffers
-    if((gx != NULL) && (gy != NULL)) {
-        memcpy(gx, public.gx, SK_SIZE);
-        memcpy(gy, public.gy, SK_SIZE);
-    }
-
-    // return success
-    return status;
-}
-
-sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sealed, uint32_t sealed_size, uint8_t *signature, uint32_t signature_size) {
-    // invalid parameter handling
-    if((data == NULL) || (data_size == 0)) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    } else if((sealed == NULL) || (sealed_size == 0)) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    }
-    
-    // declare need structures
-    sgx_ecc_state_handle_t ecc_handle;
-    sgx_ec256_private_t private;
-    sgx_ec256_public_t public;
-
-    // open ecc handle
-    sgx_status_t status;
-    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
-        return status;
-    }
-
-    // try unseal keypair
-    sgx_status_t seal_status;
-    if(seal_status = unseal_key_pair(sealed, &private, NULL) != SGX_SUCCESS) {
-        if((status = sgx_ecc256_create_key_pair(&private, &public, ecc_handle)) != SGX_SUCCESS) {
-            sgx_ecc256_close_context(ecc_handle);
-            return status;
-        }
-    }
-
-    // create signature
-    sgx_ec256_signature_t ecc_signature;
-    if((status = sgx_ecdsa_sign(data, data_size, &private, &ecc_signature, ecc_handle)) != SGX_SUCCESS) {
-        sgx_ecc256_close_context(ecc_handle);
-        return status;
-    }
-
-    // TODO: possible wrong endianess for other programms
-    // copy signature to return buffer
-    if((signature == NULL) || (signature_size == 0)) {
-        sgx_ecc256_close_context(ecc_handle);
-        return SGX_ERROR_INVALID_PARAMETER;
-    }
-    memcpy(signature, ecc_signature.x, SI_SIZE);
-
-    // seal the key
-    if((seal_status != SGX_SUCCESS) && (sealed != NULL)) {
-        seal_status = seal_key_pair(&private, &public, &sealed, sealed_size);
-    }
-
-    // close ecc handle and return success
-    sgx_ecc256_close_context(ecc_handle);
-    return seal_status;
-}
-
-sgx_status_t verify_firmware(const uint8_t *data, uint32_t data_size, const uint8_t *sealed, uint32_t sealed_size, const uint8_t *public_key, uint32_t public_key_size, const uint8_t *signature, uint32_t signature_size) {
-    // invalid parameter handling
-    if((data == NULL) || (data_size == 0)) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    } else if(((sealed == NULL) || (sealed_size == 0)) && ((public_key == NULL) || (public_key_size == 0))) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    } else if((sealed != NULL) && (public_key != NULL)) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    } else if((signature == NULL) || (signature_size == 0)) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    }
-
-    // declare need structures
-    sgx_ec256_signature_t ecc_signature;
-    sgx_ecc_state_handle_t ecc_handle;
-    sgx_ec256_public_t public;
-
-    // invalid signature
-    if(signature_size > SI_SIZE) {
-        return SGX_ERROR_INVALID_PARAMETER;
-    }
-
-    // open ecc handle
-    sgx_status_t status;
-    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
-        return status;
-    }
-
-    // copy signature into struct
-    memcpy(ecc_signature.x, signature, SI_SIZE);
-
-    // verify signature from staff or enclave
-    if(public_key != NULL) {
-        // invalid public key
-        if(public_key_size != PK_SIZE) {
-            sgx_ecc256_close_context(ecc_handle);
-            return SGX_ERROR_INVALID_PARAMETER;
-        }
-
-        // copy public key into struct
-        memcpy(public.gx, public_key, PK_SIZE);
-    } else {
-        // unseal public key
-        if(unseal_key_pair(sealed, NULL, &public) != SGX_SUCCESS) {
-            sgx_ecc256_close_context(ecc_handle);
-            return SGX_ERROR_UNEXPECTED;
-        }
-    }
-
-    // verify signature
-    uint8_t result;
-    sgx_status_t verification_status = sgx_ecdsa_verify(data, data_size, (const sgx_ec256_public_t *)&public, (const sgx_ec256_signature_t *)&ecc_signature, &result, ecc_handle);
-
-    // handle failed verification process
-    if(verification_status != SGX_SUCCESS) {
-        result = verification_status;
-    }
-
-    // close handle and return result
-    sgx_ecc256_close_context(ecc_handle);
-    return result;
-}
\ No newline at end of file