Make empty byte arrays pass CheckSignatureEncoding()

Makes it possible to compactly provide a delibrately invalid signature
for use with CHECK(MULTI)SIG. For instance with BIP19 if m != n invalid
signatures need to be provided in the scriptSig; prior to this change
those invalid signatures would need to be large DER-encoded signatures.

Note that we may want to further expand on this change in the future by
saying that only OP_0 is a "valid" invalid signature; BIP19 even with
this change is inherently malleable as the invalid signatures can be any
validly encoded DER signature.

Rebased-From: 2fa9a8ec86033b809a1c48f0396c3482c0d5d33c
Github-Pull: #5627

0 files changed, 0 insertions, 0 deletions