Recognize encryption from UDIF

Question

I have created a savings bundle and encrypted it with the standard SHA 2 algorithm with the usual hard disk utility.

Can I see the encryption anywhere?

They cannot be found in the disk utility or with hdiutil imageinfo.

Answer 1

From what I gather, you're saying that you have created an encrypted .dmg image file using Disk Utility.

You write that it is encrypted "standard SHA 2 algorithm", but this doesn't really make sense as SHA-2 is not an encryption algorithm, but rather a hash function. I assume you mean that you have used the standard 128-bit AES encryption that Disk Utility offers by default.

You can verify that the image file is encrypted by running:

hdiutil info

In the output it will state:

image-encrypted : TRUE

only if the image file is encrypted.

If you want more specific details about the encryption used, you can run this command:

hdiutil imageinfo myimage.dmg

This requires that you know the password to decrypt the image.

For an encrypted image it will show the following under "Properties":

Encrypted: true

And under "Backing Store Information" it will list the type of encryption:

Encryption: AES-128

UPDATE: In the comments you have indicated that you really wanted to know this information specifically for "sparse bundles" (not savings bundles). In that case, you can still use the above mentioned commands to find out if the files are encrypted, however it does not display the encryption algorithm used.

This information is available in a header placed in the token file in the root of the sparse bundle. You can use third party software such as this to decode that information.