pcp/TODO

key++: normalize id and lc()

allow signing using an alternate secret key, like in pcpdecrypt()

malloc() new pointers in functions only if not NULL, e.g. pcp_gennonce()

generalize file i/0, open+close only in src/, print msg if using stdin or stdout
  - sign + crypt done. key exports und imports to follow

check pub key count in pcp.c before calling verify signature, croak if count==0

Update pod key format spec.

-l show keysig, if any

vault checksum: add keysigs as well

enable formats for secret key exports as well

Unitttests:
  - sometimes "no matching pub key in vault, while it's there
    Cause:
      echo HALLO | ../src/pcp1 -V vcl -e -O testencrypted -i 0xA907B927849B39F9
        ok 28 - check-crypto-unencrypted-secret-message
      public key exported.  <=== ???

  - sometimes secret key is empty

  Possible causes: the unittest segfaults and unittest.pl doesn't
  catch it, esp. if the prepare call segfaults. Or, there's some bug
  in unittest.pl, however the issue started as I switched to the
  pcpstream api.


Python binding, e.g.:
py % cdll.LoadLibrary("libsodium.so.8")
<CDLL 'libsodium.so.8', handle 800776c00 at 80192a3d0>
py % nacl = CDLL("libsodium.so.8")
py % hash = create_string_buffer('\000' * 64)
py % hash
<ctypes.c_char_Array_65 object at 0x80182c560>
py % hash.raw
'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x...
py % key = create_string_buffer('a' * 32)
py % nacl.crypto_hash_sha256(pointer(hash), pointer(key), 32)
0
py % hash.raw
';\xa3\xf5\xf4;\x92`&\x83\xc1\x9a\xeeb\xa2\x03B\xb0\x84\...
py %