Squashed 'bip-0352/secp256k1lab/' content from commit 44dc4bd

git-subtree-dir: bip-0352/secp256k1lab
git-subtree-split: 44dc4bd893b8f03e621585e3bf255253e0e0fbfb

src/secp256k1lab/keys.py

@@ -0,0 +1,15 @@
+from .secp256k1 import GE, G
+from .util import int_from_bytes
+
+# The following function is based on the BIP 327 reference implementation
+# https://github.com/bitcoin/bips/blob/master/bip-0327/reference.py
+
+
+# Return the plain public key corresponding to a given secret key
+def pubkey_gen_plain(seckey: bytes) -> bytes:
+    d0 = int_from_bytes(seckey)
+    if not (1 <= d0 <= GE.ORDER - 1):
+        raise ValueError("The secret key must be an integer in the range 1..n-1.")
+    P = d0 * G
+    assert not P.infinity
+    return P.to_bytes_compressed()