Disk Utility info shows encrypted disk is not encrypted!
The proper command to check if a dmg is encrypted or not is:
hdiutil isencrypted /../../encrypted.dmg
or more detailed with the encryption type:
hdiutil imageinfo /../../encrypted.dmg
Examples:
hdiutil isencrypted /Users/user/Desktop/Untitled.dmg
encrypted: YES
blocksize: 512
uuid: 24895029-49B1-469D-A154-B8344B7CD6EB
private-key-count: 0
passphrase-count: 1
max-key-count: 1
version: 2
and/or
hdiutil imageinfo /Users/user/Desktop/Untitled.dmg
<Enter disk's password>
Backing Store Information:
URL: file:///Users/user/Desktop/Untitled.dmg
Name: Untitled.dmg
Class Name: CEncryptedEncoding
Encryption: AES-256
Backing Store Information:
URL: file:///Users/user/Desktop/Untitled.dmg
Name: Untitled.dmg
Class Name: CBSDBackingStore
Class Name: CRawDiskImage
Checksum Type: none
Size Information:
Total Bytes: 100020736
Compressed Ratio: 1
Sector Count: 195353
Total Non-Empty Bytes: 100020736
Compressed Bytes: 100020736
Total Empty Bytes: 0
Format: UDRW
Format Description: raw read/write
Checksum Value:
Properties:
Encrypted: true
Kernel Compatible: false
Checksummed: false
Software License Agreement: false
Partitioned: false
Compressed: no
Segments:
0: /Users/user/Desktop/Untitled.dmg
partitions:
partition-scheme: GUID
block-size: 512
partitions:
0:
partition-name: Protective Master Boot Record
partition-start: 0
partition-synthesized: true
partition-length: 1
partition-hint: MBR
1:
partition-name: GPT Header
partition-start: 1
partition-synthesized: true
partition-length: 1
partition-hint: Primary GPT Header
2:
partition-name: GPT Partition Data
partition-start: 2
partition-synthesized: true
partition-length: 32
partition-hint: Primary GPT Table
3:
partition-name:
partition-start: 34
partition-synthesized: true
partition-length: 6
partition-hint: Apple_Free
4:
partition-UUID: 17698BE2-A406-43AA-9195-8D1F1AAECE6B
partition-name: disk image
partition-hint-UUID: 48465300-0000-11AA-AA11-00306543ECAC
partition-start: 40
partition-number: 1
partition-length: 195280
partition-hint: Apple_HFS
partition-filesystems:
HFS+:
5:
partition-name: GPT Partition Data
partition-start: 195320
partition-synthesized: true
partition-length: 32
partition-hint: Backup GPT Table
6:
partition-name: GPT Header
partition-start: 195352
partition-synthesized: true
partition-length: 1
partition-hint: Backup GPT Header
burnable: false
Resize limits (per hdiutil resize -limits):
min cur max
36072 195280 60572704
I can only guess why diskutil doesn't show that the image is encrypted. It's either a glitch or diskutil only rates FileVault as disk encryption.