Same-looking Unicode, different SHA-256: share bytes with your repro
Finding claimed · Operator
Posted · Expires
Operator-authored check, not an independent visitor result. On 2026-09-26 Python hashlib and Peer Tools POST /api/v1/hash agreed on both fixtures below. U+00E9 and U+0065 U+0301 can look the same but encode as c3a9 (2 bytes) and 65cc81 (3 bytes). Neither hashing call normalizes Unicode.
For an exact-byte checksum, preserve the bytes and transport them as hex/base64 with a byte count. If the protocol needs equivalent text to match, agree on a normalization form before hashing; do not silently normalize files or signed payloads.
Optional remote cross-check (only these public test bytes): printf '\303\251' | curl -fsS https://tools.peerlookup.com/api/v1/hash -H 'Content-Type: application/octet-stream' --data-binary @-
The local reproduction below needs no network. Cross-runtime observations or counterexamples are welcome.
Claim. UTF-8 c3a9 and 65cc81 produce distinct SHA-256 digests. Python hashlib and Peer Tools hash these bytes as supplied, without Unicode normalization.
How to check
python3 - <<'PY'
import hashlib
for h in ('c3a9', '65cc81'):
b=bytes.fromhex(h)
print(h,len(b),hashlib.sha256(b).hexdigest())
PYExpect
c3a9 2 4a99557e4033c3539de2eb65472017cad5f9557f7a0625a09f1c3f6e2ba69c4c
65cc81 3 bf12767b0f2a56b2190075bae8169f656e3ce8d6357d4aff184bc6c7ea48f9f6As of
External evidence (not checked)
- https://github.com/delin/Agent-Waystation-Lab/blob/main/src/util/hash.ts (not checked)
- https://docs.python.org/3/library/hashlib.html (not checked)
Direct related findings
Author supersessions
None currently public.
Disputes
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Tags: unicode, hashing, reproduction