For validating the ChaCha20 encryption/decryption algorithm written in VB.NET, I am looking for more ChaCha20 test vectors that are based on the final spec for ChaCha20 that can be found here. See the test vector in sub-chapter 2.3.2. This test vector validates my code which provides the exact result specified in the test vector. (there is an almost identical vector later in on the document, two blocks with different counters, validates perfectly against that as well).
Test vectors that I found in draft ChaCha20 specifications do not give the exact same result as specified in these draft spec test vectors. They are using a different-size nonce compared to the final spec (draft 64 bits, final 96 bits) and the state of the counter is not specified (I assume it is 0).
Of course the question is if just one or two test vectors is enough to validate how an encryption algorithm is coded, my hunch is that more is very preferable but saying that as a true cryptography amateur.
It would be great to have more test vectors based on the final ChaCha20 spec to assure the code provides the exact results needed. Thank you!
2.3.2. Test Vector for the ChaCha20 Block Function For a test vector, we will use the following inputs to the ChaCha20 block function: o Key = 00:01:02:03:04:05:06:07:08:09:0a:0b:0c:0d:0e:0f:10:11:12:13: 14:15:16:17:18:19:1a:1b:1c:1d:1e:1f. The key is a sequence of octets with no particular structure before we copy it into the ChaCha state. o Nonce = (00:00:00:09:00:00:00:4a:00:00:00:00) o Block Count = 1. After setting up the ChaCha state, it looks like this: ChaCha state with the key setup. 61707865 3320646e 79622d32 6b206574 03020100 07060504 0b0a0908 0f0e0d0c 13121110 17161514 1b1a1918 1f1e1d1c 00000001 09000000 4a000000 00000000 After running 20 rounds (10 column rounds interleaved with 10 "diagonal rounds"), the ChaCha state looks like this: ChaCha state after 20 rounds 837778ab e238d763 a67ae21e 5950bb2f c4f2d0c7 fc62bb2f 8fa018fc 3f5ec7b7 335271c2 f29489f3 eabda8fc 82e46ebd d19c12b4 b04e16de 9e83d0cb 4e3c50a2 Finally, we add the original state to the result (simple vector or matrix addition), giving this: ChaCha state at the end of the ChaCha20 operation e4e7f110 15593bd1 1fdd0f50 c47120a3 c7f4d1c7 0368c033 9aaa2204 4e6cd4c3 466482d2 09aa9f07 05d7c214 a2028bd9 d19c12b5 b94e16de e883d0cb 4e3c50a2