Add btcec compatibility tests

Tests our implementation against github.com/btcsuite/btcd/btcec/v2:

- TestKeyDerivationCompatibility: verify public keys match btcec
- TestOurSignatureVerifiesWithBtcec: our signatures verify with btcec
- TestBtcecSignatureVerifiesWithOurs: btcec signatures verify with ours
- TestCrossSignAndVerify: bidirectional sign/verify with same keys
- TestBIP340Vectors: official BIP-340 test vectors (14 total)
- TestTaggedHashFormat: verify tagged hash structure

All tests pass - our implementation is fully compatible with btcec
for BIP-340 Schnorr signatures.

1 files changed, 10 insertions, 0 deletions

diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..3f06a00
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,10 @@
+github.com/btcsuite/btcd/btcec/v2 v2.3.6 h1:IzlsEr9olcSRKB/n7c4351F3xHKxS2lma+1UFGCYd4E=
+github.com/btcsuite/btcd/btcec/v2 v2.3.6/go.mod h1:m22FrOAiuxl/tht9wIqAoGHcbnCCaPWyauO8y2LGGtQ=
+github.com/btcsuite/btcd/chaincfg/chainhash v1.0.1 h1:q0rUy8C/TYNBQS1+CGKw68tLOFYSNEs0TFnxxnS9+4U=
+github.com/btcsuite/btcd/chaincfg/chainhash v1.0.1/go.mod h1:7SFka0XMvUgj3hfZtydOrQY2mwhPclbT2snogU7SQQc=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/decred/dcrd/crypto/blake256 v1.0.0 h1:/8DMNYp9SGi5f0w7uCm6d6M4OU2rGFK09Y2A4Xv7EE0=
+github.com/decred/dcrd/crypto/blake256 v1.0.0/go.mod h1:sQl2p6Y26YV+ZOcSTP6thNdn47hh8kt6rqSlvmrXFAc=
+github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1 h1:YLtO71vCjJRCBcrPMtQ9nqBsqpA1m5sE92cU+pd5Mcc=
+github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1/go.mod h1:hyedUtir6IdtD/7lIxGeCxkaw7y45JueMRL4DIyJDKs=