Module metadata 

SD-PKE: metadata encryption

Spec pseudocode:

def KGen():
    (skS, pkS) = KEM_H.KGen()
    return (skS, pkS)

def Enc(pkR, m):
    c, cp = HPKE.SealBase(pkR=pkR, info=None, aad=None, pt=m)
    return (c, cp)

def Dec(skR, c, cp):
    m = HPKE.OpenBase(enc=c, skR=skR, info=None, aad=None, ct=cp)
    return m

Structs

MetadataCiphertext

SD-PKE ciphertext (c, c'): X-Wing encapsulation c together with HPKE ciphertext c'.

MetadataKeyPair

A (MetadataPrivateKey, MetadataPublicKey) SD-PKE keypair.

MetadataPrivateKey

The recipient’s metadata private key (sk_R^PKE in the spec).

MetadataPublicKey

The recipient’s metadata public key (pk_R^PKE in the spec).

Functions

decrypt

SD-PKE.Dec: decrypt (c, c') using recipient key sk_r, returning message m.

encrypt

SD-PKE.Enc: encrypt message m to recipient key pk_r, returning (c, c').

keygen

SD-PKE.KGen: generate a MetadataKeyPair.