//  blnk.h
//  2019-02-23  Markku-Juhani O. Saarinen <mjos@pqshield.com>
//  Copyright (C) 2019, PQShield Ltd. Please see LICENSE.

//  The BLNK2 "core" state manipulation functions.

#ifndef _BLNK_H_
#define _BLNK_H_

#include <stdint.h>
#include <stddef.h>

//  Get instantiation
#include "sneik_param.h"

//  Internal errors indicate a line in the code
#define BLNK_ERR   (-(__LINE__))

//  Padding identifiers
#define BLNK_LAST   0x01                    // Last (padded) block of domain
#define BLNK_FULL   0x02                    // Full state input (0: RATE input)
#define BLNK_A2B    0x04                    // Alice -> Bob
#define BLNK_B2A    0x08                    // Bob -> Alice
#define BLNK_AD     0x10                    // Authenticated data (in)
#define BLNK_ADF    (BLNK_AD | BLNK_FULL)   // Full-state assoc. data (in)
#define BLNK_KEY    0x20                    // Secret key (in)
#define BLNK_KEYF   (BLNK_KEY | BLNK_FULL)  // Secret key/nonce block (in)
#define BLNK_HASH   0x40                    // Hash/Authentication tag (out)
#define BLNK_PTCT   0x70                    // Plaintext or Ciphertext (in/out)
#define BLNK_BIT7   0x80                    // Reserved

// Domain indicator
typedef uint8_t blnk_dom_t;

//  State
typedef struct {
    union {
        uint8_t  u8[BLNK_BLOCK];            // permutation state
        uint32_t u32[(BLNK_BLOCK + 3) / 4]; // for alignment
    } st;
    uint8_t pos, rate;                      // data position and rate
    uint8_t rounds;                         // number of rounds
} blnk_t;

//  Initialize with given rate and number of rounds
void blnk_clr(blnk_t *st, size_t rate, uint8_t rounds);

//  End a data element (compulsory between different types)
void blnk_fin(blnk_t *st, blnk_dom_t dom);

//  Absorb data
void blnk_put(blnk_t *st, blnk_dom_t dom, const void *in, size_t len);

//  Squeeze data
void blnk_get(blnk_t *st, blnk_dom_t dom, void *out, size_t len);

//  Encrypt data
void blnk_enc(blnk_t *st, blnk_dom_t dom,
    void *out, const void *in, size_t len);

//  Decrypt data
void blnk_dec(blnk_t *st, blnk_dom_t dom,
    void *out, const void *in, size_t len);

//  Compare to output (0 == equal)
int blnk_cmp(blnk_t *st, blnk_dom_t dom, const void *in, size_t len);

//  Ratchet for forward security
void blnk_ratchet(blnk_t *ctx);

#endif  /* _BLNK_H_ */