S3proxy can't download encrypted objects with .s3enc prefix

[MrKonoreyich]

aws s3 cp --endpoint-url http://localhost:81 myfile s3://bucketname/object works fine. In s3 panel it shows with .s3enc prefix

When I'm trying to download this object, aws s3 cp stucking at:

2026-01-19 09:23:51,417 - ThreadPoolExecutor-1_0 - s3transfer.futures - DEBUG - Submitting task GetObjectTask(transfer_id=0, {'bucket': 'bucketname', 'key': 'test_6gb.bin', 'extra_args': {'Range': 'bytes=7038042112-', 'IfMatch': '"bb54bdbf2d9a858bd2cb80d8ffe63930-840"'}}) to executor <s3transfer.futures.BoundedExecutor object at 0x7c885f189160> for transfer request: 0.
2026-01-19 09:23:51,417 - ThreadPoolExecutor-1_0 - s3transfer.utils - DEBUG - Acquiring 0
2026-01-19 09:23:51,417 - ThreadPoolExecutor-1_0 - s3transfer.utils - DEBUG - Releasing acquire 0/None

But if I use aws s3 cp --endpoint-url http://localhost:81 s3://bucketname/file.s3enc file it downloads normally, but without decryption.

docker-compose.yml:

services:
  s3proxy:
    image: andrewgaul/s3proxy:latest
    container_name: s3proxy
    ports:
      - "81:80"
    environment:
      - S3PROXY_AUTHORIZATION=aws-v2-or-v4
      - S3PROXY_IDENTITY=xxx
      - S3PROXY_CREDENTIAL=xxx
      
      - S3PROXY_ENCRYPTED_BLOBSTORE=true
      - S3PROXY_ENCRYPTED_BLOBSTORE_PASSWORD=my-encryption-password-123
      - S3PROXY_ENCRYPTED_BLOBSTORE_SALT=my-salt-456

      
      - JCLOUDS_PROVIDER=aws-s3-sdk
      - JCLOUDS_ENDPOINT=xxx
      - JCLOUDS_IDENTITY=xxx
      - JCLOUDS_CREDENTIAL=xxx
      - JCLOUDS_REGION=xxx


      - LOG_LEVEL=info
      - S3PROXY_CORS_ALLOW_ALL=true
     
    restart: unless-stopped

[MrKonoreyich]

After a short investigation, I found that it gets stuck at:

Decryption decryption =
                    new Decryption(secretKey, delegate(), meta, offset, length);

(EncryptedBlobStore.java)

The constructor takes ~1 minute to complete, after which it finally sends a response. However, by that time the AWS CLI client has already timed out and retries the request, leading to an infinite loop of retries and timeouts.