Andrew Boyson / crypto

A simple library to support serving https.

Dependents:   oldheating gps motorhome heating

explanation.txt@2:82268409e83f, 2019-07-31 (annotated)

Committer:
andrewboyson
Date:
Wed Jul 31 15:12:34 2019 +0000
Revision:
2:82268409e83f
Parent:
0:be515c9019e3
Child:
6:819c17738dc2
A lot of tidying. Not working yet.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 0:be515c9019e3 1 SHA
andrewboyson 0:be515c9019e3 2 secure hash algorithm
andrewboyson 0:be515c9019e3 3 - it is deterministic, meaning that the same message always results in the same hash
andrewboyson 0:be515c9019e3 4 - it is quick to compute the hash value for any given message
andrewboyson 0:be515c9019e3 5 - it is infeasible to generate a message that yields a given hash value
andrewboyson 0:be515c9019e3 6 - it is infeasible to find two different messages with the same hash value
andrewboyson 0:be515c9019e3 7 - a small change to a message should change the hash value so extensively that
andrewboyson 0:be515c9019e3 8 the new hash value appears uncorrelated with the old hash value (avalanche effect)
andrewboyson 0:be515c9019e3 9
andrewboyson 0:be515c9019e3 10 HMAC
andrewboyson 0:be515c9019e3 11 keyed-hash message authentication code or hash-based message authentication code
andrewboyson 0:be515c9019e3 12 - it is a message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key.
andrewboyson 0:be515c9019e3 13 - it may be used to simultaneously verify both the data integrity and the authentication of a message
andrewboyson 2:82268409e83f 14 - used to sign a message with a symmetrical key
andrewboyson 2:82268409e83f 15
andrewboyson 2:82268409e83f 16 Full RSA handshake
andrewboyson 2:82268409e83f 17 ===================
andrewboyson 2:82268409e83f 18 ClientHello -->
andrewboyson 2:82268409e83f 19 <-- ServerHello
andrewboyson 2:82268409e83f 20 <-- Certificate
andrewboyson 2:82268409e83f 21 <-- ServerHelloDone
andrewboyson 2:82268409e83f 22 ClientKeyExchange -->
andrewboyson 2:82268409e83f 23 ChangeCipherSpec -->
andrewboyson 2:82268409e83f 24 Finished -->
andrewboyson 2:82268409e83f 25 <-- ChangeCipherSpec
andrewboyson 2:82268409e83f 26 <-- Finished
andrewboyson 2:82268409e83f 27
andrewboyson 2:82268409e83f 28
andrewboyson 2:82268409e83f 29 Short RSA handshake
andrewboyson 2:82268409e83f 30 ===================
andrewboyson 2:82268409e83f 31 ClientHello -->
andrewboyson 2:82268409e83f 32 <-- ServerHello
andrewboyson 2:82268409e83f 33 <-- ChangeCipherSpec
andrewboyson 2:82268409e83f 34 <-- Finished
andrewboyson 2:82268409e83f 35 ChangeCipherSpec -->
andrewboyson 2:82268409e83f 36 Finished -->
andrewboyson 2:82268409e83f 37