// open an encrypted box
func CryptoBoxOpen(box, nounce, sk, pk []byte) ([]byte, error) {
boxbuff := NewBuffer(box)
defer boxbuff.Free()
// check sizes
if len(pk) != int(C.crypto_box_publickeybytes()) {
err := errors.New("len(pk) != crypto_box_publickey_bytes")
return nil, err
}
if len(sk) != int(C.crypto_box_secretkeybytes()) {
err := errors.New("len(sk) != crypto_box_secretkey_bytes")
return nil, err
}
if len(nounce) != int(C.crypto_box_macbytes()) {
err := errors.New("len(nounce) != crypto_box_macbytes()")
return nil, err
}
pkbuff := NewBuffer(pk)
defer pkbuff.Free()
skbuff := NewBuffer(sk)
defer skbuff.Free()
nouncebuff := NewBuffer(nounce)
defer nouncebuff.Free()
resultbuff := malloc(boxbuff.size - nouncebuff.size)
defer resultbuff.Free()
// decrypt
res := C.crypto_box_open_easy(resultbuff.uchar(), boxbuff.uchar(), C.ulonglong(boxbuff.size), nouncebuff.uchar(), pkbuff.uchar(), skbuff.uchar())
if res != 0 {
return nil, errors.New("crypto_box_open_easy failed")
}
// return result
return resultbuff.Bytes(), nil
}
func BoxOpenEasy(messageOut []byte, cypherText []byte, nonce, pk, sk []byte) int {
checkSize(messageOut, BoxMacBytes()+len(cypherText), "message output")
checkSize(nonce, BoxNonceBytes(), "nonce")
checkSize(pk, BoxPublicKeyBytes(), "public key")
checkSize(sk, BoxSecretKeyBytes(), "secret key")
return int(C.crypto_box_open_easy(
(*C.uchar)(&messageOut[0]),
(*C.uchar)(&cypherText[0]), (C.ulonglong)(len(cypherText)),
(*C.uchar)(&nonce[0]),
(*C.uchar)(&pk[0]),
(*C.uchar)(&sk[0])))
}