Process Services PXI

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Process Services PXI "pxi:ps9"[edit]

Command Header (Pre 2.0) Command Header (Post 2.0) Available since system version Description
0x000100C6 0x000100C6 1.0.0-0 This crypts a raw message with RSA.
0x00020284 0x00020284 1.0.0-0 SignRsaSha256
0x00030284 0x00030284 1.0.0-0 VerifyRsaSha256
0x00040140 Removed 1.0.0-0, removed with 2.0.0-2 SetAesKey
0x000501C4 0x000401C4 1.0.0-0 EncryptDecryptAes
0x00060284 0x00050284 1.0.0-0 EncryptSignDecryptVerifyAesCcm
0x00070000 0x00060000 1.0.0-0 GetRomId. This reads 0x40-bytes from gamecard command 0xC6 (gamecard-uniqueID), and returns the first 0x10-bytes from that since the rest of the command reply is all 0xFF-bytes.
0x00080000 0x00070000 1.0.0-0 GetRomId2. The first u8 this returns is from GetRomMakerCode, the following 0x10-bytes are from encrypting the 0x10-bytes which GetRomId also returns. This is encrypted with AES-CBC, the regular normal-key and IV set by Process9 for this are loaded from the Process9 .rodata section.
0x00090000 0x00080000 1.0.0-0 GetCTRCardAutoStartupBit
0x000A0000 0x00090000 1.0.0-0 GetRomMakerCode
0x000B0000 0x000A0000 1.0.0-0 GetLocalFriendCodeSeed
0x000C0000 0x000B0000 1.0.0-0 GetDeviceId
0x000D0042 0x000C0042 1.0.0-0 SeedRNG
0x000E0042 0x000D0042 1.0.0-0 GenerateRandomBytes
0x04010084 0x04010084 8.1.0-0_New3DS GenerateAmiiboHMAC. New_3DS-only. cmd[1] = insize, cmd[2] = outsize, cmd[3] = (insize<<8) | 0x4, cmd[4] = inbufptr, cmd[5] = (outsize<<8) | 0x14, and cmd[6] = outbufptr.
0x04020082 0x04020082 8.1.0-0_New3DS GenerateAmiiboKeyData. New_3DS-only. cmd[1] = insize, cmd[2] = u8 flag, cmd[3] = (insize<<8) | 0x4, cmd[4] = inbufptr.
0x04030044 0x04030044 8.1.0-0_New3DS AmiiboEncryptDecrypt. New_3DS-only.
0x04040044 0x04040044 8.1.0-0_New3DS AmiiboEncryptDecryptDev. New_3DS-only.

These RSA commands are an interface for using the RSA engine. The system will hang when it attempts to use a >RSA-2048 RSA bit-size with the RSA engine, since the RSA engine does not support >RSA-2048. These RSA commands have an input field specifying what RSA bit-size to use, but the RSA padding code is hard-coded to use RSA-2048.

The New3DS 0x040X commands(used for Amiibo crypto) were removed with 9.3.0-21, the code for that was moved into NFC-module.

Command 0x04010084[edit]

The input buffer size must be <=0x1E0-bytes, and the out buffer size must be >0 and <=0x20-bytes. This calculates a SHA256-HMAC over the input buffer using the current already-generated Amiibo HMAC key(generated_amiibodata+0x20), the output hash is then written to the out buffer.

Command 0x04020082[edit]

This is used for Amiibo key generation. 0x30-bytes are generated. The input buffer size must be 0x40-bytes.

The input u8 must be either zero or non-zero, the used value varies depending on what crypto(AES/HMAC) operation is done after the crypto init.

Structure of the input buffer:

Offset Size Description
0x0 0x2 This is the raw Amiibo-write counter u16 from page[4] byte1.
0x2 0xE All-zero.
0x10 0x8 This is the first 8-bytes of the NFC tag serial-number(page0-1).
0x18 0x8 Same 8-bytes as above.
0x20 0x20 This is the plaintext hash from NFC tag page[0x18], which is the hash listed under the page 0x15 section here.

Command 0x04030044[edit]

This is used for the actual Amiibo AES crypto, max input buffer size is same as command 0x04010084. AES-CTR is used here. Normal-key = generated_amiibodata+0x0, CTR = generated_amiibodata+0x10(see command 0x04010084 regarding generated_amiibodata).

Command 0x04040044[edit]

Similar to 0x04030044, except this is devunit-only with dev-only keys.

RSA Context[edit]

Offset Size Description
0x0 0x100 Modulo
0x100 0x100 Exponent
0x200 0x4 RSA bit-size.
0x204 0x1 Exponent Type. 0 = Short Exponent, 1 = Long Exponent. See notes below.
0x205 0x3 Padding

This context structure is fixed to 0x208-bytes.

Notes on exponents:

  • When the type is a short exponent, the exponent field is used as an u32 field with little endianness.
    • An example use of this type is to load the common public exponent, 0x10001.
  • When a long exponent is set, the exponent field is a buffer of a big endian number instead.