Kem class¶

class crsyspqc.Kem¶

Key-Encapsulation Mechanism (KEM) functions.

class Alg¶

Key-Encapsulation Mechanism (KEM) algorithms.

static keygen(alg, params='')¶

Generate an encapsulation/decapsulation key pair (ek, dk).

Parameters:

alg (Kem.Alg) – Kem algorithm.
params (str) – Optional parameter to pass known test random material of exactly 64 bytes (d||z) encoded in hexadecimal [default=add fresh randomness].

Returns:

A key pair (ek, dk) both of type bytes.

static encaps(alg, encapkey, params='')¶

Carry out the ML-KEM encapsulation algorithm.

Parameters:

alg (Kem.Alg) – Kem algorithm.
encapkey (bytes) – Encapsulation key ek
params (str) – Optional parameter to pass known test random material of exactly 32 bytes (m) encoded in hexadecimal [default=add fresh randomness].

Returns:

A pair (ss, ct). Secret shared key ss and ciphertext ct both of type bytes.

static decaps(alg, ct, decapkey)¶

Carry out the ML-KEM decapsulation algorithm.

Parameters:

alg (Kem.Alg) – Kem algorithm.
ct (bytes) – Ciphertext ct
decapkey (bytes) – Decapsulation key dk (in expanded or 64-byte “seed” form)

Returns:

shared secret key, ss. On failure, ss will contain a pseudo-random value.

Return type:

bytes

static encapkey_size(alg)¶

Return length in bytes of encapsulation key (“public key”) for given algorithm.

static decapkey_size(alg)¶

Return length in bytes of expanded decapsulation key (“private key”) for given algorithm.

static ciphertext_size(alg)¶

Return length in bytes of ciphertext ct for given algorithm.

static sharedkey_size(alg)¶

Return length in bytes of shared secret key ss for given algorithm.

static alg_name(alg)¶

Get the algorithm name from its Alg code.

Example

>>> Kem.alg_name(Kem.Alg.ML_KEM_768)
'ML-KEM-768'