2017年5月追记：

（3月2日23时-3月3日2时）

# 一、声明

The Idolmaster Cinderella Girls Starlight Stage 软件和相关媒体的著作权为 Bandai Namco Entertainment Inc. 所有。本系列文章仅从兴趣出发，研究数据反向过程。在此不会给出完整的反向过程、反向结果和源代码，只给出思路和部分非关键数据。

# 四、vgmtoolbox 的拯救

A.D.X. supports a simple encryption scheme which XORs values from a linear congruential pseudorandom number generator with the block scale values. This method is computationally inexpensive to decrypt (in keeping with A.D.X.’s real-time decoding) yet renders the encrypted files unusable. The encryption is active when the “Flags” value in the header is 0x08. As XOR is symmetric the same method is used to decrypt as to encrypt. The encryption key is a set of three 16-bit values: the multiplier, increment, and start values for the linear congruential generator (the modulus is 0x8000 to keep the values in the 15-bit range of valid block scales). Typically all A.D.X. files from a single game will use the same key.