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| author | Nikita Burnashev <nikita.burnashev@gmail.com> | 2023-04-16 12:46:55 +0300 |
|---|---|---|
| committer | Solomon Peachy <pizza@shaftnet.org> | 2023-05-17 13:19:31 -0400 |
| commit | e232f69214cfe0ad83e8a6051c58ef54754e59bb (patch) | |
| tree | dfe36ac87d182c2e3f8f4a99ea74ad3492a1f1dd /firmware/export | |
| parent | 72c0e49b41b0da4a43a4852771eed3767fc675ad (diff) | |
| download | rockbox-e232f69214cfe0ad83e8a6051c58ef54754e59bb.tar.gz rockbox-e232f69214cfe0ad83e8a6051c58ef54754e59bb.zip | |
atjboottool: gzipped fw files, option for big-endian fw, clarify ECIES in fwu
Added fw modifications required to unpack real world player dumps.
Documented more fwu header fields, magic numbers and finite field arithmetics (extended Euclidean for inverse, long division for reducing modulo field_poly).
v3 encryption used is standard RC4 with the key additionally ciphered by the Elliptic Curve Integrated Encryption Scheme.
Either sect233k1 (NIST K-233) or sect163r2 (NIST B-163) curves can be used, with the former overwhelmingly prevailing, being hardwired in SDK's maker.exe. Using a private/public key scheme is superfluous because both are stored in the firmware, with the added level of complexity likely serving the purpose of obfuscation. The private key is generated at random with each invokation.
None of KDF or MAC from ECIES are used, RC4 key is directly xored with the shared secret. The random number r used to calculate rG isn't stored, but that's unimportant since only krG == rkG is actually used in the encryption.
Change-Id: Ieacf8cc744bc90c7c5582dd724b2c10a41bfc191
Diffstat (limited to 'firmware/export')
0 files changed, 0 insertions, 0 deletions