# Reference vectors¶

In addition to the policy of keeping any code path in PyNaCl covered by unit tests, the output from cryptographic primitives and constructions must be verified as being conformant to the reference implementations or standards.

## Imported reference vectors¶

Wherever possible it is the PyNaCl project’s policy to use existing reference vectors for primitives or constructions. These vectors should ideally be in their original format, but it is acceptable to make minimal changes to ease parsing at our discretion.

### Box construction¶

The reference vector for testing the nacl.public.Box implementation come from libsodium’s test/default/box.c and test/default/box2.c and the corresponding expected outputs in test/default/box.exp and test/default/box2.exp

### SecretBox construction¶

The reference vector for testing the nacl.secret.SecretBox implementation come from libsodium’s test/default/secretbox.c and the corresponding expected outputs in test/default/secretbox.exp

### chacha20poly1305¶

The reference vectors for both the legacy draft-agl-tls-chacha20poly1305 and the IETF ratified rfc7539 chacha20poly1305 constructions are taken from libressl version 2.5.5 tests/aeadtests.txt, excluding the shortened authentication tag vectors, since libsodium only supports full sized tags.

### xchacha20poly1305¶

The reference vector for the xchacha20poly1305 construction is taken from the first test in libsodium’s test/default/aead_xchacha20poly1305.c, which defines the parameters, and the corresponding expected output from aead_xchacha20poly1305.exp.

### siphash24 and siphashx24¶

The reference vectors for both the original and the 128 bit variants of the siphash-2-4 construction are taken from the reference code sources. In particular, the original expected results come from siphash’s vectors.h, while the key and the input messages have been generated following the respective definitions in siphash’s test.c.

## Custom generated reference vectors¶

In cases where there are no standardized test vectors, or the available ones are not applicable to libsodium’s implementation, test vectors are custom generated.