Freescale's SEC block has built-in Data Encryption
Key(DEK) Blob Protocol which provides a method for
protecting a DEK for non-secure memory storage.
SEC block protects data in a data structure called
a Secret Key Blob, which provides both confidentiality
and integrity protection.
Every time the blob encapsulation is executed,
a AES-256 key is randomly generated to encrypt the DEK.
This key is encrypted with the OTP Secret key
from SoC. The resulting blob consists of the encrypted
AES-256 key, the encrypted DEK, and a 16-bit MAC.
During decapsulation, the reverse process is performed
to get back the original DEK. A caveat to the blob
decapsulation process, is that the DEK is decrypted
in secure-memory and can only be read by FSL SEC HW.
The DEK is used to decrypt data during encrypted boot.
Commands added
--------------
dek_blob - encapsulating DEK as a cryptgraphic blob
Commands Syntax
---------------
dek_blob src dst len
Encapsulate and create blob of a len-bits DEK at
address src and store the result at address dst.
Signed-off-by: Raul Cardenas <Ulises.Cardenas@freescale.com>
Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
Signed-off-by: Ulises Cardenas <ulises.cardenas@freescale.com>
Signed-off-by: Ulises Cardenas-B45798 <Ulises.Cardenas@freescale.com>
This patch does the following:
1. The function names for encapsulation and decapsulation
were inconsitent in freescale's implementation and cmd_blob file.
This patch corrects the issues.
2. The function protopye is also modified to change the length parameter
from u8 to u32 to allow encapsulation and decapsulation of larger images.
3. Modified the description of km paramter in the command usage for better
readability.
Signed-off-by: Gaurav Rana <gaurav.rana@freescale.com>
Reviewed-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
Freescale's SEC block has built-in Blob Protocol which provides
a method for protecting user-defined data across system power
cycles. SEC block protects data in a data structure called a Blob,
which provides both confidentiality and integrity protection.
Encapsulating data as a blob
Each time that the Blob Protocol is used to protect data, a
different randomly generated key is used to encrypt the data.
This random key is itself encrypted using a key which is derived
from SoC's non volatile secret key and a 16 bit Key identifier.
The resulting encrypted key along with encrypted data is called a blob.
The non volatile secure key is available for use only during secure boot.
During decapsulation, the reverse process is performed to get back
the original data.
Commands added
--------------
blob enc - encapsulating data as a cryptgraphic blob
blob dec - decapsulating cryptgraphic blob to get the data
Commands Syntax
---------------
blob enc src dst len km
Encapsulate and create blob of data $len bytes long
at address $src and store the result at address $dst.
$km is the 16 byte key modifier is also required for
generation/use as key for cryptographic operation. Key
modifier should be 16 byte long.
blob dec src dst len km
Decapsulate the blob of data at address $src and
store result of $len byte at addr $dst.
$km is the 16 byte key modifier is also required for
generation/use as key for cryptographic operation. Key
modifier should be 16 byte long.
Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
Raul Cardenas
gaurav rana
Ruchika Gupta