diff --git a/client.cpp b/client.cpp
index 35a1050..d9fc88f 100644
--- a/client.cpp
+++ b/client.cpp
@@ -18,46 +18,6 @@
 
 #include "helper.h"
 
-// block cipher encryption function
-int block_encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key, unsigned char *iv, unsigned char *ciphertext)
-{
-    /* Declare cipher context */
-    EVP_CIPHER_CTX *ctx;
-
-    int len, ciphertext_len;
-
-    /* Create and initialise the context */
-    ctx = EVP_CIPHER_CTX_new();
-    if (!ctx)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Initialise the encryption operation. */
-    // choice for aes_256 ref: https://stackoverflow.com/questions/1220751/how-to-choose-an-aes-encryption-mode-cbc-ecb-ctr-ocb-cfb
-    if (EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv) != 1)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Provide the message to be encrypted, and obtain the encrypted output. EVP_EncryptUpdate can be called multiple times if necessary */
-    if (EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len) != 1)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Finalize the encryption. Further cipher text bytes may be written at this stage. */
-    if (EVP_EncryptFinal_ex(ctx, ciphertext + len, &ciphertext_len) != 1)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Clean up */
-    EVP_CIPHER_CTX_free(ctx);
-
-    return ciphertext_len + len;
-}
-
 int main(void)
 {
     load_env(".env");
diff --git a/latex/H3_CSE4303_ZheyuanWu.pdf b/latex/H3_CSE4303_ZheyuanWu.pdf
index 420d004..8e84fb7 100644
Binary files a/latex/H3_CSE4303_ZheyuanWu.pdf and b/latex/H3_CSE4303_ZheyuanWu.pdf differ
diff --git a/latex/H3_CSE4303_ZheyuanWu.tex b/latex/H3_CSE4303_ZheyuanWu.tex
index c5709a7..7a11434 100644
--- a/latex/H3_CSE4303_ZheyuanWu.tex
+++ b/latex/H3_CSE4303_ZheyuanWu.tex
@@ -489,46 +489,6 @@ int main(void)
 
 #include "helper.h"
 
-// block cipher encryption function
-int block_encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key, unsigned char *iv, unsigned char *ciphertext)
-{
-    /* Declare cipher context */
-    EVP_CIPHER_CTX *ctx;
-
-    int len, ciphertext_len;
-
-    /* Create and initialise the context */
-    ctx = EVP_CIPHER_CTX_new();
-    if (!ctx)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Initialise the encryption operation. */
-    // choice for aes_256 ref: https://stackoverflow.com/questions/1220751/how-to-choose-an-aes-encryption-mode-cbc-ecb-ctr-ocb-cfb
-    if (EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv) != 1)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Provide the message to be encrypted, and obtain the encrypted output. EVP_EncryptUpdate can be called multiple times if necessary */
-    if (EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len) != 1)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Finalize the encryption. Further cipher text bytes may be written at this stage. */
-    if (EVP_EncryptFinal_ex(ctx, ciphertext + len, &ciphertext_len) != 1)
-    {
-        ERR_print_errors_fp(stderr);
-    }
-
-    /* Clean up */
-    EVP_CIPHER_CTX_free(ctx);
-
-    return ciphertext_len + len;
-}
-
 int main(void)
 {
     load_env(".env");