Merge bitcoin#15826: Pure python EC

b679785 Add comments to Python ECDSA implementation (John Newbery)
8c7b932 Pure python EC (Pieter Wuille)

Pull request description:

  This removes the dependency on OpenSSL for the interaction tests, by providing a pure-Python
  toy implementation of secp256k1.

ACKs for commit b67978:
  jnewbery:
    utACK b679785

Tree-SHA512: 181445eb08b316c46937b80dc10aa50d103ab1fdddaf834896c0ea22204889f7b13fd33cbcbd00ddba15f7e4686fe0d9f8e8bb4c0ad0e9587490c90be83966dc

test/functional/feature_assumevalid.py

@@ -32,7 +32,7 @@
 import time
 
 from test_framework.blocktools import (create_block, create_coinbase)
-from test_framework.key import CECKey
+from test_framework.key import ECKey
 from test_framework.messages import (
     CBlockHeader,
     COutPoint,
@@ -104,9 +104,9 @@ def run_test(self):
         self.blocks = []
 
         # Get a pubkey for the coinbase TXO
-        coinbase_key = CECKey()
-        coinbase_key.set_secretbytes(b"horsebattery")
-        coinbase_pubkey = coinbase_key.get_pubkey()
+        coinbase_key = ECKey()
+        coinbase_key.generate()
+        coinbase_pubkey = coinbase_key.get_pubkey().get_bytes()
 
         # Create the first block with a coinbase output to our key
         height = 1

test/functional/feature_block.py

@@ -14,7 +14,7 @@
     get_legacy_sigopcount_block,
     MAX_BLOCK_SIGOPS,
 )
-from test_framework.key import CECKey
+from test_framework.key import ECKey
 from test_framework.messages import (
     CBlock,
     COIN,
@@ -86,9 +86,9 @@ def run_test(self):
         self.bootstrap_p2p()  # Add one p2p connection to the node
 
         self.block_heights = {}
-        self.coinbase_key = CECKey()
-        self.coinbase_key.set_secretbytes(b"horsebattery")
-        self.coinbase_pubkey = self.coinbase_key.get_pubkey()
+        self.coinbase_key = ECKey()
+        self.coinbase_key.generate()
+        self.coinbase_pubkey = self.coinbase_key.get_pubkey().get_bytes()
         self.tip = None
         self.blocks = {}
         self.genesis_hash = int(self.nodes[0].getbestblockhash(), 16)
@@ -528,7 +528,7 @@ def run_test(self):
             tx.vin.append(CTxIn(COutPoint(b39.vtx[i].sha256, 0), b''))
             # Note: must pass the redeem_script (not p2sh_script) to the signature hash function
             (sighash, err) = SignatureHash(redeem_script, tx, 1, SIGHASH_ALL)
-            sig = self.coinbase_key.sign(sighash) + bytes(bytearray([SIGHASH_ALL]))
+            sig = self.coinbase_key.sign_ecdsa(sighash) + bytes(bytearray([SIGHASH_ALL]))
             scriptSig = CScript([sig, redeem_script])
 
             tx.vin[1].scriptSig = scriptSig
@@ -1284,7 +1284,7 @@ def sign_tx(self, tx, spend_tx):
             tx.vin[0].scriptSig = CScript()
             return
         (sighash, err) = SignatureHash(spend_tx.vout[0].scriptPubKey, tx, 0, SIGHASH_ALL)
-        tx.vin[0].scriptSig = CScript([self.coinbase_key.sign(sighash) + bytes(bytearray([SIGHASH_ALL]))])
+        tx.vin[0].scriptSig = CScript([self.coinbase_key.sign_ecdsa(sighash) + bytes(bytearray([SIGHASH_ALL]))])
 
     def create_and_sign_transaction(self, spend_tx, value, script=CScript([OP_TRUE])):
         tx = self.create_tx(spend_tx, 0, value, script)

test/functional/p2p_segwit.py

@@ -9,7 +9,7 @@
 import time
 
 from test_framework.blocktools import create_block, create_coinbase, add_witness_commitment, get_witness_script, WITNESS_COMMITMENT_HEADER
-from test_framework.key import CECKey, CPubKey
+from test_framework.key import ECKey
 from test_framework.messages import (
     BIP125_SEQUENCE_NUMBER,
     CBlock,
@@ -100,7 +100,7 @@ def get_p2pkh_script(pubkeyhash):
 def sign_p2pk_witness_input(script, tx_to, in_idx, hashtype, value, key):
     """Add signature for a P2PK witness program."""
     tx_hash = SegwitVersion1SignatureHash(script, tx_to, in_idx, hashtype, value)
-    signature = key.sign(tx_hash) + chr(hashtype).encode('latin-1')
+    signature = key.sign_ecdsa(tx_hash) + chr(hashtype).encode('latin-1')
     tx_to.wit.vtxinwit[in_idx].scriptWitness.stack = [signature, script]
     tx_to.rehash()
 
@@ -1479,10 +1479,9 @@ def test_uncompressed_pubkey(self):
 
         # Segwit transactions using uncompressed pubkeys are not accepted
         # under default policy, but should still pass consensus.
-        key = CECKey()
-        key.set_secretbytes(b"9")
-        key.set_compressed(False)
-        pubkey = CPubKey(key.get_pubkey())
+        key = ECKey()
+        key.generate(False)
+        pubkey = key.get_pubkey().get_bytes()
         assert_equal(len(pubkey), 65)  # This should be an uncompressed pubkey
 
         utxo = self.utxo.pop(0)
@@ -1512,7 +1511,7 @@ def test_uncompressed_pubkey(self):
         tx2.vout.append(CTxOut(tx.vout[0].nValue - 1000, script_wsh))
         script = get_p2pkh_script(pubkeyhash)
         sig_hash = SegwitVersion1SignatureHash(script, tx2, 0, SIGHASH_ALL, tx.vout[0].nValue)
-        signature = key.sign(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
+        signature = key.sign_ecdsa(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
         tx2.wit.vtxinwit.append(CTxInWitness())
         tx2.wit.vtxinwit[0].scriptWitness.stack = [signature, pubkey]
         tx2.rehash()
@@ -1566,7 +1565,7 @@ def test_uncompressed_pubkey(self):
         tx5.vin.append(CTxIn(COutPoint(tx4.sha256, 0), b""))
         tx5.vout.append(CTxOut(tx4.vout[0].nValue - 1000, CScript([OP_TRUE])))
         (sig_hash, err) = SignatureHash(script_pubkey, tx5, 0, SIGHASH_ALL)
-        signature = key.sign(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
+        signature = key.sign_ecdsa(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
         tx5.vin[0].scriptSig = CScript([signature, pubkey])
         tx5.rehash()
         # Should pass policy and consensus.
@@ -1579,9 +1578,9 @@ def test_uncompressed_pubkey(self):
     @subtest
     def test_signature_version_1(self):
 
-        key = CECKey()
-        key.set_secretbytes(b"9")
-        pubkey = CPubKey(key.get_pubkey())
+        key = ECKey()
+        key.generate()
+        pubkey = key.get_pubkey().get_bytes()
 
         witness_program = CScript([pubkey, CScriptOp(OP_CHECKSIG)])
         witness_hash = sha256(witness_program)
@@ -1716,7 +1715,7 @@ def test_signature_version_1(self):
 
         script = get_p2pkh_script(pubkeyhash)
         sig_hash = SegwitVersion1SignatureHash(script, tx2, 0, SIGHASH_ALL, tx.vout[0].nValue)
-        signature = key.sign(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
+        signature = key.sign_ecdsa(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
 
         # Check that we can't have a scriptSig
         tx2.vin[0].scriptSig = CScript([signature, pubkey])