feat: 전화번호 저장 시 암호화하여 저장

[maark1106]

📌 관련 이슈

사용자 전화번호 암호화하여 데이터베이스에 저장 [#220]

🛠️ 작업 내용

• 사용자 전화번호 저장 시 데이터베이스 암호화
  
  
  

🎯 리뷰 포인트

📎 커밋 범위 링크

[Copilot]

Pull Request Overview

This PR introduces phone number encryption when storing user data, ensuring that sensitive data is encrypted before being persisted in the database.

• Updated the Student entity to use an encrypted converter and increased the column length for the phone number.
• Added a new endpoint and service method to retrieve the decrypted phone number.
• Implemented an EncryptionService and associated EncryptedConverter to perform AES encryption and decryption.

Reviewed Changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/main/java/com/team/buddyya/student/service/StudentService.java	Added a new service method to retrieve the user's phone number.
src/main/java/com/team/buddyya/student/domain/Student.java	Updated the phoneNumber field to use encryption with an increased column length.
src/main/java/com/team/buddyya/student/controller/UserController.java	Added an endpoint for fetching the phone number.
src/main/java/com/team/buddyya/common/service/EncryptionService.java	Introduced AES encryption and decryption functionality.
src/main/java/com/team/buddyya/common/service/EncryptedConverter.java	Created an AttributeConverter to integrate encryption with JPA.
src/main/java/com/team/buddyya/common/exception/CommonExceptionType.java	Added a specific exception type for encryption errors.
src/main/java/com/team/buddyya/common/config/ConverterConfig.java	Configured the EncryptedConverter with the EncryptionService dependency.

Files not reviewed (1)

• src/main/resources/db/migration/V11__increase_phone_number_length.sql: Language not supported

Comments suppressed due to low confidence (3)

src/main/java/com/team/buddyya/student/service/StudentService.java:177

• [nitpick] The name 'findStudentService' may imply a service layer role, which could be confusing if this field is responsible for repository operations. Consider renaming it to more clearly reflect its purpose.

Student student = findStudentService.findByStudentId(studentInfo.id());

src/main/java/com/team/buddyya/common/service/EncryptionService.java:23

• Consider explicitly specifying the encryption mode and padding (for example, 'AES/ECB/PKCS5Padding') rather than relying on defaults, to ensure consistent and secure encryption behavior.

Cipher cipher = Cipher.getInstance(ALGORITHM);

src/main/java/com/team/buddyya/student/domain/Student.java:34

• With the phone number field now storing an encrypted value and the column length increased to 128, please verify that any phone number validations and constraints elsewhere in the application have been updated accordingly.

@Convert(converter = EncryptedConverter.class)