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akwizgran created page: BSP

akwizgran
2015-03-23 17:19:45 +00:00
parent 13cd2f6dc4
commit ffeb822a95
1 changed files with 3 additions and 3 deletions
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BTP.markdown

@@ -12,12 +12,12 @@ We use || to denote concatenation, double quotes to denote an ASCII string, int(
BTP uses the following cryptographic primitives:
* A pseudo-random function, MAC(k, m)
* A message authentication code, MAC(k, m)
* An authenticated cipher, ENC(k, n, m) and DEC(k, n, m), where n is a nonce
All keys are key_len bytes and all nonces are nonce_len bytes. The output of MAC(k, m) is mac_len bytes, and the output of ENC(k, n, m) is auth_len bytes longer than m. For simplicity we require that mac_len == key_len.
> Implementation note: The current version of BTP uses HMAC-SHA-256 as the pseudo-random function and AES-256-GCM as the authenticated cipher. The next version will use BLAKE2s as the pseudo-random function and XSalsa20-Poly1305 as the authenticated cipher. In both cases, key_len == 32, mac_len == 32, nonce_len == 24, and auth_len == 16.
> Implementation note: The current version of BTP uses HMAC-SHA-256 as the message authentication code and AES-256-GCM as the authenticated cipher. The next version will use BLAKE2s as the message authentication code and XSalsa20-Poly1305 as the authenticated cipher. In both cases, key_len == 32, mac_len == 32, nonce_len == 24, and auth_len == 16.
### Initial state
@@ -36,7 +36,7 @@ The devices must also agree which of them will play the role of Alice and which
### Key derivation
BTP's key derivation function is based on a pseudo-random function:
BTP's key derivation function is based on a message authentication code:
KDF(k, x_1, ..., x_n) == MAC(k, pack(x_1) || ... || pack(x_n))