# Constantine
# Copyright (c) 2018-2019    Status Research & Development GmbH
# Copyright (c) 2020-Present Mamy André-Ratsimbazafy
# Licensed and distributed under either of
#   * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
#   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.

import
  std/unittest,
  ../constantine/ciphers/chacha20

suite "[Cipher] Chacha20":
  test "Test vector 1 - RFC8439":
    let plaintext = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it."
    let ciphertext = [
      byte 0x6e, 0x2e, 0x35, 0x9a, 0x25, 0x68, 0xf9, 0x80, 0x41, 0xba, 0x07, 0x28, 0xdd, 0x0d, 0x69, 0x81,
           0xe9, 0x7e, 0x7a, 0xec, 0x1d, 0x43, 0x60, 0xc2, 0x0a, 0x27, 0xaf, 0xcc, 0xfd, 0x9f, 0xae, 0x0b,
           0xf9, 0x1b, 0x65, 0xc5, 0x52, 0x47, 0x33, 0xab, 0x8f, 0x59, 0x3d, 0xab, 0xcd, 0x62, 0xb3, 0x57,
           0x16, 0x39, 0xd6, 0x24, 0xe6, 0x51, 0x52, 0xab, 0x8f, 0x53, 0x0c, 0x35, 0x9f, 0x08, 0x61, 0xd8,
           0x07, 0xca, 0x0d, 0xbf, 0x50, 0x0d, 0x6a, 0x61, 0x56, 0xa3, 0x8e, 0x08, 0x8a, 0x22, 0xb6, 0x5e,
           0x52, 0xbc, 0x51, 0x4d, 0x16, 0xcc, 0xf8, 0x06, 0x81, 0x8c, 0xe9, 0x1a, 0xb7, 0x79, 0x37, 0x36,
           0x5a, 0xf9, 0x0b, 0xbf, 0x74, 0xa3, 0x5b, 0xe6, 0xb4, 0x0b, 0x8e, 0xed, 0xf2, 0x78, 0x5e, 0x42,
           0x87, 0x4d
    ]
    let key = [
      byte 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
           0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
           0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
           0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f
    ]
    let nonce = [byte 0, 0, 0, 0, 0, 0, 0, 0x4a, 0, 0, 0, 0]

    var data = newSeq[byte](plaintext.len)
    copyMem(data[0].addr, plaintext[0].unsafeAddr, plaintext.len)

    doAssert cast[seq[byte]](plaintext) != ciphertext

    discard chacha20_cipher(key, counter = 1, nonce, data)
    doAssert data == ciphertext

    discard chacha20_cipher(key, counter = 1, nonce, data)
    doAssert data == cast[seq[byte]](plaintext)