1. [n. d.]. Cipher (Java SE 11 & JDK 11). https://docs.oracle.com/en/java/javase/11/docs/api/java.base/javax/crypto/Cipher.html
2. [n. d.]. gnu.crypto.cipher (GNU cryptographic primitives and tools version 2.0.0). https://www.gnu.org/software/gnu-crypto/manual/api/gnu/crypto/cipher/package-summary.html
3. [n. d.]. IBlockCipher (GNU cryptographic primitives and tools version 2.0.0). https://www.gnu.org/software/gnu-crypto/manual/api/gnu/crypto/cipher/IBlockCipher.html
4. [n. d.]. JCA (Java Cryptography Architecture) Usage Memo - Qiita (in Japanese). https://qiita.com/opengl-8080/items/2f0b3cf19b73c260d2ab
5. [n. d.]. "What is Java’s Map type? How to write initialization and loop processing & Summary of useful methods" - TRAINOCAMP (in Japanese). https://camp.trainocate.co.jp/magazine/java-map/