Module stream 

Attachment AES-256-GCM over a file, a chunk at a time: the cipher of super::decrypt_data (16-byte nonce, 16-byte tag appended) without the file ever sitting whole in memory.

GCM is CTR encryption plus a GHASH over the ciphertext, and both run incrementally. The catch is that the tag only speaks at the end, so plaintext is written to a file the caller keeps out of sight until this returns Ok.

Structs

StreamedFile

What one pass over a downloaded file learned.

Constants

CANCELLED

What a pass stopped by its caller returns.

Functions

decrypt_file

Decrypt src (ciphertext || tag) into dst, hashing both sides on the way. dst holds unauthenticated plaintext until this returns: on any error it is removed, and a tag mismatch is reported as a decryption failure.

decrypt_file_with_progress

decrypt_file, telling progress each new whole percentage of the file opened. progress answering false stops the pass, as for encrypt_file_with_progress.

encrypt_file

Encrypt src into dst (ciphertext || tag), the counterpart of decrypt_file. Returns the SHA-256 and length of what was written: the blob a server will hold.

encrypt_file_with_progress

encrypt_file, telling progress each new whole percentage of the file sealed. progress answering false stops the pass: nothing is written and the error says it was cancelled.

hash_file

SHA-256 of a file, read a chunk at a time.

place_download

Put a verified download into the download directory under name: an identical file already there (same name, size and hash) is reused and src dropped; otherwise src moves to a free spelling of the name. Returns where it landed.