Texas Instruments CC3235 SimpleLink Series - DES3 DES - CFB Feedback Mode; DES Global Initialization; DES Algorithm Type Configuration

DES Module Programming Guide – Low-Level Programming Models www.ti.com
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SWRU543–January 2019
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Data Encryption Standard Accelerator (DES)
Figure 18-4. DES3DES – CFB Feedback Mode
18.4 DES Module Programming Guide – Low-Level Programming Models
18.4.1 Surrounding Modules Global Initialization
18.4.1.1 Main Sequence – DES Global Initialization
The steps listed in Table 18-2 initialize the DES
Table 18-2. DES Global Initialization
Step Register/Bit Field/Programming Model Value
Enable clock CRYPTOCLKEN [0] 0x1
Select the algorithm type (DES or 3DES). See the programming models.
Select the operating mode (ECB, CBC or
CFB).
DES_CTRL[5:4] MODE –
IF: ECB operating mode not selected DES_CTRL[5:4] MODE ≠ 0x0
Load the initialization vector LSW. DES_IV_L[31:0] IV_L –
Load the initialization vector MSW. DES_IV_H[31:0] IV_H –
Define the cryptographic data length. DES_LENGTH[31:0] LENGTH –
ENDIF
Select encryption or decryption DES_CTRL[2] DIRECTION –
18.4.1.2 Subsequence – Configure the DES Algorithm Type
The subsequence listed in Table 18-3 details the DES algorithm type settings.
Table 18-3. DES Algorithm Type Configuration
Step Register/Bit Field/Programming Model Value
Load key 1 LSW. DES_KEY1_L[31:0] KEY1_L –
Load key 1 MSW. DES_KEY1_H[31:0] KEY1_H –
Select DES algorithm. DES_CTRL[3] TDES 0x0