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参数资料
| 型号： | DS2703UT |
| 英文描述： | SHA-1 Battery Pack Authentication IC |
| 中文描述： | SHA - 1的电池组认证IC |
| 文件页数： | 7/20页 |
| 文件大小： | 238K |
| 代理商： | DS2703UT |
DS2703 SHA-1 Battery Pack Authentication IC
7 of 20
SHA Computation
The variables A, B, C, D, E and constants H0, H1, H2, H3, and H4 are initialized as follows:
A
:=
67452301h
H0
B
:=
EFCDAB89h
H1
C
:=
98BADCFEh
H2
D
:=
10325476h
H3
E
:=
C3D2E1F0h
H4
The final values of variables A, B, C, D, and E are generated by looping through the following set of computations
for t = 0 to 79 (discarding any carry-out). Finally, the H0-H4 constants are added to the A-E variables respectively,
which are then concatenated to form the 160-bit MAC, ABCDE.
for ( t = 0 to 79 )
{
TMP
:=
S
5
(A) + F
t
(B,C,D) + W
t
+ K
t
+ E
E
:=
D
D
:=
C
C
:=
S
30
(B)
B
:=
A
A
:=
TMP
}
160-bit MAC := (A+H0) | (B+H1) | (C+H2) | (D+H3) | (E+H4)
DS2703 AUTHENTICATION COMMANDS
WRITE CHALLENGE [0Ch].
This command writes 64 bits in the message block. The LSB of the 64-bit data can
begin immediately after the MSB of the command has been completed. If more than 8 bytes are written, the final
value in the challenge register will be indeterminate. The Compute MAC and Compute Next Secret (with or without
ROM ID) function commands clear the challenge value. Therefore the Write Challenge command
must be issued
prior to every
Compute MAC or Compute Next Secret command for reliable results.
COMPUTE MAC WITHOUT ROM ID [36h].
This command initiates a SHA-1 computation on the 512 bit block
comprised of words W0 - W15. The 64-bit secret and the 64-bit challenge are loaded in the message block. The
DS2703 takes up to 100us after receiving this command to begin computing the MAC. This gives the host ample
time to connect the DQ pin to a low impedance node prior to the high current demand computation. The DQ pin
must not fall below V
PULLUP_MIN
during the computation period, t
COMP
. The host must release the DQ pin for 1-Wire
data communications (i.e. terminate the low source impedance mode). After the DQ pin has returned to normal
impedance, the host must write eight write zero time slots and then issue 160 read time slots to get the MAC. The
32-bit registers A, B, C, D, and E are used during every cycle of the hash algorithm and their final values at
calculation cycle t=79 are added to the values H0-H4 and stored in registers A-E. The new word ABCDE is now the
MAC. After issuing the command and waiting a minimum of t
COMP
, the host reads the 20-byte MAC
.
This command
allows the use of a master secret and message digest response independent of the ROM ID.
COMPUTE MAC WITH ROM ID [35h]
This command is structured the same as the Compute MAC without ROM ID, except that the ROM ID is loaded to
the message block. Including the ROM ID unique to each DS2703 in the MAC computation allows the use of a
unique secret in each token and a master secret in the host device. See application note “White Paper 4”, available
at
http://www.maxim-ic.com
, for more information.
:=
:=
:=
:=
:=
67452301h
EFCDAB89h
98BADCFEh
10325476h
C3D2E1F0h
SHA-1 related commands used while authenticating a battery or peripheral device are summarized in Table for
convenience. Four additional commands for clearing, computing and locking of the Secret are described in detail in
the following section.
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PDF描述 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS2704 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:1280-Bit EEPROM with SHA-1 Authentication |
| DS2704-500-WAFER | 功能描述:电可擦除可编程只读存储器 RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 |
| DS2704E+ | 制造商:Maxim Integrated Products 功能描述:1024 BIT MEM W/SHA-1 AUTH L/F - Rail/Tube |
| DS2704G+ | 功能描述:电可擦除可编程只读存储器 1280-Bit 电可擦除可编程只读存储器 w/SHA-1 Authent RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 |
| DS2704G+T&R | 制造商:Maxim Integrated Products 功能描述:EEPROM SERL-1WIRE 1.25KBIT 5PAGES X 32 3.3V/5V 6TDFN EP - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC EEPROM 1.25KBIT 6TDFN 制造商:Maxim Integrated Products 功能描述:EEPROM 1280-Bit EEPROM w/SHA-1 Authent |
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