2f11731a8e
* Refactor NpTicket parser and add NpTicket signature documentation * Update TickerBuilder chaining style * Fix SectionHeader position returning wrong value * Don't attempt to parse ticket if it is less than 8 bytes
2.7 KiB
PS3 Authentication Tickets
Authentication tickets, commonly referred to as NpTickets or X-I-5 tickets are binary blobs used by third-party game servers to identify and authenticate users.
For more information about the format of tickets see either the article written by the psdevwiki or the write-up done by the Skate 3 server team
PSN uses ECDSA for securely verifying that a ticket was indeed generated by PSN and hasn't been tampered with
The exact specifics of the system are unknown but it's believed that each game or in some instances groups of games (The LBP series for example) are given a single unique identifier such that any tickets with that identifier are guaranteed to be signed using the same private key. Therefore, with that identifier in hand you can determine what public key you should use to verify a ticket.
ECDSA specifics
The PSN implementation of ECDSA signing uses the secp192r1 curve also known as nistp192. The hashing algorithm used is SHA-1.
The message is the entire ticket sans the signature (the last 56 bytes).
The RPCN implementation of ECDSA signing uses the secp224k1 curve. The hashing algorithm used is SHA-224.
The message for RPCN is the body section of the ticket including the body header.
The public key for RPCN is available on the RPCN repo or in the known keys section.
Finding public keys
Without going into the specifics of ECDSA it's possible to derive the public key given that you have the original message and know the curve parameters and hashing algorithm.
A C# program has been written that can parse tickets and give the public keys that correspond to the private key used to sign the message.
The project is available on GitHub at https://github.com/Slendy/PubKeyFinder
While it's possible to find the public key given a single ticket, due to the way ECDSA works there are always 2 possible points that can validate a signature. If you have more than one ticket though then each ticket will have at least one matching point which can be used to identify the actual public key.
Known Public Keys
RPCN (All Games)
identifier: 5250434E (RPCN in ASCII)
x: b07bc0f0addb97657e9f389039e8d2b9c97dc2a31d3042e7d0479b93
y: d81c42b0abdf6c42191a31e31f93342f8f033bd529c2c57fdb5a0a7d
LittleBigPlanet Series (PSN)
identfier: 719F1D4A
x: 39c62d061d4ee35c5f3f7531de0af3cf918346526edac727
y: a5d578b55113e612bf1878d4cc939d61a41318403b5bdf86
Skate 3 (PSN)
identifier: 382DE58D
x: a93f2d73da8fe51c59872fad192b832f8b9dabde8587233
y: 93131936a54a0ea51117f74518e56aae95f6baff4b29f999