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| author | Peter Todd <pete@petertodd.org> | 2015-01-09 05:52:57 -0500 |
|---|---|---|
| committer | Peter Todd <pete@petertodd.org> | 2015-01-09 06:03:22 -0500 |
| commit | 2fa9a8ec86033b809a1c48f0396c3482c0d5d33c (patch) | |
| tree | 4cd6abf6979cf22bc9962accb7472083e6daa830 /src/script | |
| parent | d0c97bbe70a6876dadedfbf672387371c9c849d1 (diff) | |
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.
Diffstat (limited to 'src/script')
| -rw-r--r-- | src/script/interpreter.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index d0f75ab672..8a06f3d118 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -189,6 +189,11 @@ bool static IsDefinedHashtypeSignature(const valtype &vchSig) { } bool static CheckSignatureEncoding(const valtype &vchSig, unsigned int flags, ScriptError* serror) { + // Empty signature. Not strictly DER encoded, but allowed to provide a + // compact way to provide an invalid signature for use with CHECK(MULTI)SIG + if (vchSig.size() == 0) { + return true; + } if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsDERSignature(vchSig)) { return set_error(serror, SCRIPT_ERR_SIG_DER); } else if ((flags & SCRIPT_VERIFY_LOW_S) != 0 && !IsLowDERSignature(vchSig, serror)) { |