Add ability to handle sse-c with add-header

[geraldhansen]

Hi there,

I like to use s3cmd for sse-c, for this I use the add-header parameter in this way:

secret="12345678901234567890123456789012" 
key=$(echo -n $secret | base64)
key_md5=$(echo -n $secret | openssl dgst -md5 -binary | openssl enc -base64)

s3cmd --add-header=x-amz-server-side-encryption-customer-algorithm:AES256 \
    --add-header=x-amz-server-side-encryption-customer-key:"${key}" \
    --add-header=x-amz-server-side-encryption-customer-key-MD5:"${key_md5}" \
    --remove-header=x-amz-server-side-encryption \
    put test.txt s3://aws-encryption-test/test_encrypted.txt
s3cmd --add-header=x-amz-server-side-encryption-customer-algorithm:AES256 \
    --add-header=x-amz-server-side-encryption-customer-key:"${key}" \
    --add-header=x-amz-server-side-encryption-customer-key-MD5:"${key_md5}" \
    --remove-header=x-amz-server-side-encryption \
    get s3://aws-encryption-test/test_encrypted.txt test_downloaded.txt

This commit will suppress md5-sum checks for sse-c uploaded and downloaded
files. And use extra-headers also for get requests to download
sse-c enrypted files again.

[PoplarYang]

I found a error:

secret="12345678901234567890123456789012" 
key=$(echo -n $secret | base64)
key_md5=$(echo -n $secret | openssl dgst -md5 -binary | openssl enc -base64)

s3cmd --add-header=x-amz-server-side-encryption-customer-algorithm:AES256 \
    --add-header=x-amz-server-side-encryption-customer-key:"${key}" \
    --add-header=x-amz-server-side-encryption-customer-key-MD5:"${key_md5}" \
    --remove-header=x-amz-server-side-encryption put --acl-public test.txt s3://test-src/test6.txt -vvvv
INFO: No cache file found, creating it.
INFO: Compiling list of local files...
INFO: Running stat() and reading/calculating MD5 values on 1 files, this may take some time...
INFO: Summary: 1 local files to upload
WARNING: test.txt: Owner username not known. Storing UID=501 instead.
upload: 'test.txt' -> 's3://test-src/test6.txt'  [1 of 1]
 12 of 12   100% in    0s   349.80 B/s  done
Public URL of the object is: http://ks3-bj.ksyun.com/test-src/test6.txt

s3cmd --add-header=x-amz-server-side-encryption-customer-algorithm:AES256 \
    --add-header=x-amz-server-side-encryption-customer-key:"${key}" \
    --add-header=x-amz-server-side-encryption-customer-key-MD5:"${key_md5}" \
    --remove-header=x-amz-server-side-encryption get s3://test-src/test6.txt .
download: 's3://test-src/test6.txt' -> './test6.txt'  [1 of 1]
ERROR: S3 error: 400 (MissingCustomerKey): The data is encrypted by customer key, but missing it in the request