module Netauth:sig..end
Some primitives for authentication
val hmac : h:(string -> string) ->
b:int -> l:int -> k:string -> message:string -> stringThe HMAC algorithm of RFC 2104. The function h is the hash function.
b and l are properties of h (see the RFC or below). The string
k is the key, up to b bytes. The message is authenticated.
The key k should ideally have length l. If this cannot be ensured
by other means, one should pass k = h any_k.
Common values of b and l:
h=MD5: b=64, l=16h=SHA-1: b=64, l=20See also Netsys_digests.hmac for a better implementation.
typekey_type =[ `Kc | `Ke | `Ki ]
Key types:
`Kc is used for computing checksums`Ke is used for encrypting confidential messages`Ki is used for computing integrity checksums for encrypted
messagesval derive_key_rfc3961_simplified : encrypt:(string -> string) ->
random_to_key:(string -> string) ->
block_size:int -> k:int -> usage:int -> key_type:key_type -> stringDerives a special key from a base key, as described in RFC 3961.
encrypt: Encrypts the argument with the base key and the
initial cipher state.random_to_key: Converts a random string of size k to a keyblock_size: The block size of the cipher underlying encrypt.
It is ensured that encrypt is called with strings having exactly
this many bits. (The c parameter in the RFC text.) Minimum: 40.k: The input size for random_to_key in bits. Must be divisible
by 8.usage: The usage number (here restricted to 0-255, although the
RFC would allow 32 bits). Examples for usage numbers can be found
in RFC 4121 section 2.key_type: Which key type to deriveThe output is a key as produced by random_to_key.
val xor_s : string -> string -> stringPerforms the bitwise XOR of these strings (which must have the same length)
val add_1_complement : string -> string -> stringThe addition algorithm for 1's-complement numbers. The two numbers to add are given as bitstrings (big endian), and must have the same length
val rotate_right : int -> string -> stringRotate the (big-endian) bitstring to the right by n bits. This also works for negative n (left rotation), and for n whose absolute value is greater or equal than the bit length of the string.
val n_fold : int -> string -> stringBlumenthal's n-fold algorithm for an n that is divisible by 8. (RFC 3961, section 5.1)