Bounded asset digests¶

Use digest_asset to compute a SHA-256 digest without loading a PDF, image, DICOM object, audio file, or other binary asset into memory at once.

from openmed.multimodal.digest import digest_asset

with open("synthetic-scan.dcm", "rb") as stream:
    result = digest_asset(stream, max_bytes=2 * 1024**3)

print(result.sha256)
print(result.byte_count)

Streams are read from their current position in chunks no larger than 1 MiB. Seekable streams are restored to that position on success or failure, and the helper never closes a caller-owned stream. Non-seekable streams are consumed. Passing bytes hashes the existing in-memory value directly.

max_bytes is an optional hard limit. The helper reads at most one byte beyond the limit to detect overflow, then raises DigestLimitExceededError. Its error contains only the digest_size_limit category, maximum_bytes, and bytes_read; it never includes paths, filenames, or asset content. Other stream failures raise a value-free DigestStreamError.

The result contains the lowercase 64-character SHA-256 hex digest and the exact number of bytes hashed. This helper does not open paths, validate media, scan for malware, sign content, or provide content-addressed storage.