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BIP151: Clarifications on AAD and sequence numbers.

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Christopher Jeffrey 2016-07-26 23:26:46 -07:00
parent 2ac0b472da
commit f388fef2f6
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1 changed files with 4 additions and 2 deletions
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@ -123,12 +123,14 @@ After a successful <code>encinit</code>/<code>encack</code> interaction from bot
Encrypted messages do not have the 4byte network magic.
The ciphertext payload length must be included in the AEAD MAC as AAD.
The maximum message length needs to be chosen carefully. The 4 byte length field can lead to a required message buffer of 4 GiB.
Processing the message before the authentication succeeds must not be done.
The 4byte sha256 checksum is no longer required because the AEAD.
Both peers need to track the message number (int64) of sent messages to the remote peer for building a symmetric cipher IV. Padding might be required (96bit IVs).
Both peers need to track the message sequence number (uint32) of sent messages to the remote peer for building a 64 bit symmetric cipher IV. Sequence numbers are allowed to overflow to zero after 4294967295 (2^32-1).
The encrypted payload will result decrypted in one or many unencrypted messages:
@ -156,7 +158,7 @@ The Re-Keying must be done after every 1GB of data sent or received (recommended
=== Risks ===
The encryption does not include an identity authentication scheme. This BIP does not cover a proposal to avoid MITM attacks during the encryption initialization.
The encryption does not include an identity authentication scheme. This BIP does not cover a proposal to avoid MITM attacks during the encryption initialization.
Identity authentication will be covered in another BIP and will presume communication encryption after this BIP.