Filter
Top Products
CCA Release 2.54
The following is an example of calculating the current PIN encrypting key:
W
a
= X'4567 89AB CDE '
C
a
= X'11'
S
a
1
= X'1'
T
a
1
= X'4567 89AB CDF '
T
b
1
= X'6489 F5A3 1618 2AB'
T
c
1
= X'F9AC C638 1939 44BC'
K
a
2
= X'D842 BA3 C2D1 6417'
.
.
.
S
a
20
= X'1'
T
a
20
= X'4567 89AB CDF 1'
T
b
20
= X'9D25 339B F21 6416'
T
c
20
= X'BF49 836E AE2A 42A'
K
a
20
= X'67B 395E 6CFB 63D'
Current PIN encrypting key = X'67B 395E 6CFB 6C2'
Performing the Special Encryption and Special Decryption Processes
The special encryption process consists of the following steps:
1. Name the derived unique key for the current transaction K
u
.
2. Name the clear PIN-block that was built from the user-entered PIN P
c
.
3. Perform an XOR operation with the rightmost byte of K
u
and X'FF' to produce
a variant of the key; name the result K
u
v
.
4. Perform an XOR operation with K
u
v
and P
c
; store the result in T
1
.
5. Encrypt T
1
with K
u
v
; store the result in T
2
.
6. Perform an XOR operation with K
u
v
; store the result in P
e
.
The value in P
e
is the encrypted PIN-block that the POS terminal will send.
The special decryption process consists of these steps, in reverse.
The following is an example of the special encryption process:
Current encrypting key = K
u
= X'67B 395E 6CFB 63D'
User-entered PIN = 1234
User’s primary account-number = X'412 3456 789'
Clear PIN-block (unformatted) = X'412 34FF FFFF FFFF'
Primary account-number (formatted) = X' 412 3456 789'
Clear PIN-block (ANSI format) = P
c
= X'412 74ED CBA9 876F'
Variant of PIN encrypting key = K
u
v
= X'67B 395E 6CFB 6C2'
T
1
= X'6319 4DB3 A752 E7AD'
T
2
= X'5145 3CA3 E474 2148'
P
e
= X'364E 5FD 888F 418A'
Appendix E. Financial System Verbs Calculation Methods and Data Formats E-15