Fire Emblem Awakening Growth Rate Cipher Documentation

[SciresM]

Hi there. 

As you may, or may not know, growth rates in Fire Emblem: Awakening are stored enciphered, so as to prevent easy datamining of growth rates.

As far as I can tell, the deciphering process has never been documented before.

Let's fix that, shall we? :)

As an example, I will be using Lissa's growth rates.

 

Unit Growth Rates

Growth rate data is stored, enciphered, as a sequence of 8 bytes, in the usual stat ordering (HP, Str, Mag, Skl, Spd, Lck, Def, Res).

Lissa's growth rates for example, are the highly inscrutable `20 BC AA D5 74 39 E8 BD`.

 

The conversion process is both simple, and fairly complex. To lookup the growth rate for the stat at index N (zero-indexing), we perform the calculation

INDEX = (ENCIPHERED[N]- (0x63 * ((CHARACTER_ID ^ 0xA7) - 0x21 * N) ^ 0xD9)) & 0xFF;

GROWTH_RATE = LOOKUP_TABLE[INDEX];

Where LOOKUP_TABLE is the following lookup table, found at 0x4001C in GameData.bin:

59 89 D2 D1 DE C6 47 21 BA DB C5 EC 35 BD 9F 9B 2D 7B B2 09 F7 53 99 8F C4 90 FA 34 F8 19 94 02 ED 56 40 6C F4 88 4F 2B B4 BB EB 74 B7 0D C2 A4 EE 93 CF 42 F1 17 BF F0 A5 BC 0F 6E 1B 73 8D A6 3B 50 33 E0 AF 9D DD FF FE AA CE 12 62 E2 FB C1 23 49 D6 CD 04 2F 41 15 1A 32 03 8A 14 58 0A A3 D0 71 7D D3 A0 52 BE D7 8B 48 37 13 A8 44 08 3C E3 63 F6 DF 16 7C 46 F3 07 CC 79 C3 6B 3F 81 00 20 28 AE EF 6D 8E 0E 1D 4B 95 A1 B6 D4 C7 3E E5 D8 5A 43 26 7A E4 4E 9C 30 4C C8 97 FD 54 68 C0 FC 36 1C 75 01 96 E9 1F 45 06 70 2C 29 67 2E F5 9E 92 60 3D E8 E7 66 2A 91 EA 57 A9 1E 5F 27 51 C9 65 18 AB 83 D5 85 61 0C 77 7E F9 7F 5E DC 84 5C 6A 39 4D 87 5B DA 69 E6 5D 11 82 10 55 D9 CB 8C 72 86 6F 64 80 CA A2 05 AC 4A B1 0B 38 E1 AD 31 B3 98 78 B8 22 76 9A 24 A7 25 B5 F2 B9 B0 3A

 

Okay, there's basically no chance that was clear. So let's do the calculations, to make it a bit clearer.

Suppose we want the HP growth rate. That's stat 0. Enciphered[0] is 0x20, and lissa's character ID is 4, so we calculate INDEX = (0x20 - (0x63 * ((4 ^ 0xA7) - 0x21 * 0) ^ 0xD9)) & 0xFF = 0x50. The value in the lookup table at index 0x50 is 0x23, or 35 -- Lissa's base HP growth rate.

Suppose we want the Lck growth rate. That's stat 5. Enciphered[5] is 0x39, and lissa's character ID is 4, so we calculate INDEX = (0x39 - (0x63 * ((4 ^ 0xA7) - 0x21 * 5) ^ 0xD9)) & 0xFF = 0x56. The value in the lookup table at index 0x56 is 0x41, or 65 -- Lissa's base Lck growth rate.

 

Class Growth Rates

As with unit growth rate data, class growth rate data is stored, again enciphered as a sequence of 8 bytes in the usual ordering.

Lissa's base class is Cleric, which has enciphered growth rate `11 A6 E5 D2 CF 01 67 A6`.

 

The conversion process for class growth rates proceeds much like the unit growth rate -- the formula is just different. We perform the calculation:

INDEX = (ENCIPHERED[N]- (0x23 * ((CLASS_ID ^ 0x46) - 0xF1 * N) ^ 0x78)) & 0xFF;

GROWTH_RATE = LOOKUP_TABLE[INDEX];

Where LOOKUP_TABLE is the same as it was for unit growth rates.

 

Again, walking through the calculations for Cleric:

Suppose we want the HP growth rate. That's stat 0. Enciphered[0] is 0x11, and cleric's class ID is 0x35, so we calculate INDEX = (0x11 - (0x23 * ((0x35 ^ 0x46) - 0xF1 * 0) ^ 0x78)) & 0xFF = 0x50. The value in the lookup table at index 0x50 is 0x23, or 35 -- Cleric's base HP growth rate.

Suppose we want the Lck growth rate. That's stat 5. Enciphered[5] is 0x01, and cleric's class ID is 0x35, so we calculate INDEX = (0x01 - (0x23 * ((0x35 ^ 0x46) - 0xF1 * 5) ^ 0x78)) & 0xFF = 0x7F. The value in the lookup table at index 0x7F is 0x00, or 0 -- Cleric's base Lck growth rate.

 

Hope this is clear, feel free to ask any clarifying questions, and have fun playing around with growth rates!

Edited March 16, 2017 by SciresM