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git-subtree-dir: bip-0352/secp256k1lab git-subtree-split: 44dc4bd893b8f03e621585e3bf255253e0e0fbfb
25 lines
645 B
Python
25 lines
645 B
Python
import hashlib
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# This implementation can be sped up by storing the midstate after hashing
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# tag_hash instead of rehashing it all the time.
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def tagged_hash(tag: str, msg: bytes) -> bytes:
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tag_hash = hashlib.sha256(tag.encode()).digest()
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return hashlib.sha256(tag_hash + tag_hash + msg).digest()
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def bytes_from_int(x: int) -> bytes:
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return x.to_bytes(32, byteorder="big")
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def xor_bytes(b0: bytes, b1: bytes) -> bytes:
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return bytes(x ^ y for (x, y) in zip(b0, b1))
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def int_from_bytes(b: bytes) -> int:
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return int.from_bytes(b, byteorder="big")
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def hash_sha256(b: bytes) -> bytes:
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return hashlib.sha256(b).digest()
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