diff --git a/src/main/java/com/kert/controller/PostController.java b/src/main/java/com/kert/controller/PostController.java
index 65d9796..f3787cc 100644
--- a/src/main/java/com/kert/controller/PostController.java
+++ b/src/main/java/com/kert/controller/PostController.java
@@ -2,7 +2,7 @@
 
 import com.kert.model.Post;
 import com.kert.service.PostService;
-import org.springframework.beans.factory.annotation.Autowired;
+import lombok.RequiredArgsConstructor;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
@@ -10,10 +10,10 @@
 
 @RestController
 @RequestMapping("/posts")
+@RequiredArgsConstructor
 public class PostController {
 
-    @Autowired
-    private PostService postService;
+    private final PostService postService;
 
     @PostMapping
     public ResponseEntity<Post> createPost(@RequestBody Post post) {
diff --git a/src/main/java/com/kert/dto/LoginDTO.java b/src/main/java/com/kert/dto/LoginDTO.java
index c5792a5..aac6555 100644
--- a/src/main/java/com/kert/dto/LoginDTO.java
+++ b/src/main/java/com/kert/dto/LoginDTO.java
@@ -1,6 +1,9 @@
 package com.kert.dto;
 
 import lombok.*;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Positive;
 
 @Data
 @AllArgsConstructor
@@ -8,6 +11,10 @@
 @Getter
 @Setter
 public class LoginDTO {
+    @NotNull
+    @Positive
     private Long studentId;
+
+    @NotBlank
     private String password;
 }
diff --git a/src/main/java/com/kert/dto/PasswordDTO.java b/src/main/java/com/kert/dto/PasswordDTO.java
index 79a56b0..5741819 100644
--- a/src/main/java/com/kert/dto/PasswordDTO.java
+++ b/src/main/java/com/kert/dto/PasswordDTO.java
@@ -5,6 +5,7 @@
 import lombok.NoArgsConstructor;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.Size;
+import jakarta.validation.constraints.Pattern;
 
 @Data
 @NoArgsConstructor
@@ -14,6 +15,12 @@ public class PasswordDTO {
 
     @NotBlank(message = "비밀번호는 필수 항목입니다.")
     @Size(min = 8, message = "비밀번호는 8자 이상이어야 합니다.")
+    @Pattern(regexp = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[@$!%*?&])[A-Za-z\\d@$!%*?&]{8,}$",
+            message = "비밀번호는 최소 8자 이상, 하나 이상의 대문자, 소문자, 숫자 및 특수문자가 포함되어야 합니다.")
+    @Pattern(regexp = "^[^'\";#-]*$", message = "비밀번호에 SQL Injection에 사용될 수 있는 문자를 포함할 수 없습니다.")
     private String password;
+
+    @NotBlank(message = "이전 비밀번호는 필수 항목입니다.")
+    @Pattern(regexp = "^[^'\";#-]*$", message = "이전 비밀번호에 SQL Injection에 사용될 수 있는 문자를 포함할 수 없습니다.")
     private String oldPassword;
-}
\ No newline at end of file
+}
diff --git a/src/main/java/com/kert/dto/RefreshTokenRequest.java b/src/main/java/com/kert/dto/RefreshTokenRequest.java
index 7ac908c..9d8ff74 100644
--- a/src/main/java/com/kert/dto/RefreshTokenRequest.java
+++ b/src/main/java/com/kert/dto/RefreshTokenRequest.java
@@ -3,12 +3,12 @@
 import lombok.Data;
 import lombok.AllArgsConstructor;
 import lombok.NoArgsConstructor;
-import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.NotBlank;
 
 @Data
 @NoArgsConstructor
 @AllArgsConstructor
 public class RefreshTokenRequest {
-    @NotNull
+    @NotBlank
     private String refreshToken;
 }
diff --git a/src/main/java/com/kert/dto/SignUpDTO.java b/src/main/java/com/kert/dto/SignUpDTO.java
index af25d7f..2afac37 100644
--- a/src/main/java/com/kert/dto/SignUpDTO.java
+++ b/src/main/java/com/kert/dto/SignUpDTO.java
@@ -1,6 +1,10 @@
 package com.kert.dto;
 
 import lombok.*;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Pattern;
+import jakarta.validation.constraints.Email;
+import jakarta.validation.constraints.Size;
 
 @Data
 @AllArgsConstructor
@@ -9,11 +13,28 @@
 @Setter
 public class SignUpDTO {
     private Long studentId;
+
+    @NotBlank(message = "이름은 필수 항목입니다.")
+    @Pattern(regexp = "^[a-zA-Z0-9가-힣]*$", message = "이름에는 특수문자를 포함할 수 없습니다.")
     private String name;
+
+    @NotBlank(message = "비밀번호는 필수 항목입니다.")
+    @Size(min = 8, message = "비밀번호는 8자 이상이어야 합니다.")
+    @Pattern(regexp = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[@$!%*?&])[A-Za-z\\d@$!%*?&]{8,}$",
+            message = "비밀번호는 최소 8자 이상, 하나 이상의 대문자, 소문자, 숫자 및 특수문자가 포함되어야 합니다.")
+    @Pattern(regexp = "^[^'\";#-]*$", message = "사용할 수 없는 특수문자 입니다.")
     private String password;
+
+    @NotBlank(message = "이메일은 필수 항목입니다.")
+    @Email(message = "유효한 이메일 주소를 입력하세요.")
+    @Pattern(regexp = "^[^'\";#-]*$", message = "사용할 수 없는 특수문자 입니다.")
     private String email;
+
     private String profilePicture;
+
+    @NotBlank(message = "기수는 필수 항목입니다.")
     private String generation;
-    private String major;
 
+    @NotBlank(message = "전공은 필수 항목입니다.")
+    private String major;
 }
diff --git a/src/main/java/com/kert/dto/TokenResponse.java b/src/main/java/com/kert/dto/TokenResponse.java
index 242298c..0fdbdce 100644
--- a/src/main/java/com/kert/dto/TokenResponse.java
+++ b/src/main/java/com/kert/dto/TokenResponse.java
@@ -3,11 +3,15 @@
 import lombok.Data;
 import lombok.AllArgsConstructor;
 import lombok.NoArgsConstructor;
+import jakarta.validation.constraints.NotBlank;
 
 @Data
 @NoArgsConstructor
 @AllArgsConstructor
 public class TokenResponse {
+    @NotBlank
     private String accessToken;
+
+    @NotBlank
     private String refreshToken;
-}
+}
\ No newline at end of file
diff --git a/src/main/java/com/kert/service/PostService.java b/src/main/java/com/kert/service/PostService.java
index 7def30d..441fa3d 100644
--- a/src/main/java/com/kert/service/PostService.java
+++ b/src/main/java/com/kert/service/PostService.java
@@ -2,17 +2,17 @@
 
 import com.kert.model.Post;
 import com.kert.repository.PostRepository;
-import org.springframework.beans.factory.annotation.Autowired;
+import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
 import org.springframework.transaction.annotation.Transactional;
 import java.util.List;
 
 @Service
+@RequiredArgsConstructor
 public class PostService {
 
-    @Autowired
-    private PostRepository postRepository;
+    private final PostRepository postRepository;
 
     public Post createPost(Post post) {
         return postRepository.save(post);