Man page - sntrup761(3)

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Package: libntruprime-dev
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libntruprime-dev

Manual

sntrup

NAME
SYNOPSIS
DESCRIPTION
KEY GENERATION
ENCAPSULATION
DECAPSULATION
SEE ALSO

NAME

sntrup - C API for the libntruprime implementation of the Streamlined NTRU Prime cryptosystem

SYNOPSIS

Using libntruprime:

#include <ntruprime.h>

Link with -lntruprime .

Key generation (for, e.g., sntrup1277 ):

unsigned char pk[sntrup1277_PUBLICKEYBYTES];
unsigned char sk[sntrup1277_SECRETKEYBYTES];

sntrup1277_keypair(pk,sk);

Encapsulation (for, e.g., sntrup1277 ):

unsigned char ct[sntrup1277_CIPHERTEXTBYTES];
unsigned char k[sntrup1277_BYTES];
const unsigned char pk[sntrup1277_PUBLICKEYBYTES];

sntrup1277_enc(ct,k,pk);

Decapsulation (for, e.g., sntrup1277 ):

unsigned char k[sntrup1277_BYTES];
const unsigned char ct[sntrup1277_CIPHERTEXTBYTES];
const unsigned char sk[sntrup1277_SECRETKEYBYTES];

sntrup1277_dec(k,ct,sk);

DESCRIPTION

libntruprime is an implementation of the Streamlined NTRU Prime (https://ntruprime.cr.yp.to) cryptosystem. The C API for libntruprime provides the following functions:

sntrup{653,761,857,953,1013,1277}_keypair
sntrup{653,761,857,953,1013,1277}_enc
sntrup{653,761,857,953,1013,1277}_dec

All of these functions follow the SUPERCOP API for KEMs (https://bench.cr.yp.to/call-kem.html) except that

	•		the function names are libntruprime-specific instead of `crypto_kem_*` ,
	•		message lengths are `long long` instead of `unsigned long long` , and
	•		the functions return `void` instead of `int` .

The details below use sntrup1277 as an example.

KEY GENERATION

The sntrup1277_keypair function randomly generates Alice’s secret key sk[0] , sk[1] , ..., sk[sntrup1277_SECRETKEYBYTES-1] and Alice’s corresponding public key pk[0] , pk[1] , ..., pk[sntrup1277_PUBLICKEYBYTES-1] .

ENCAPSULATION

The sntrup1277_enc function randomly generates a ciphertext ct[0] , ct[1] , ..., ct[sntrup1277_CIPHERTEXTBYTES-1] and the corresponding session key k[0] , k[1] , ..., k[sntrup1277_BYTES-1] given Alice’s public key pk[0] , pk[1] , ..., pk[sntrup1277_PUBLICKEYBYTES-1] .

DECAPSULATION

The sntrup1277_dec function, given Alice’s secret key sk[0] , sk[1] , ..., sk[sntrup1277_SECRETKEYBYTES-1] , computes the session key k[0] , k[1] , ..., k[sntrup1277_BYTES-1] corresponding to a ciphertext ct[0] , ct[1] , ..., ct[sntrup1277_CIPHERTEXTBYTES-1] that was encapsulated to Alice.