Bitmaps & Data Element Presence Quiz

Test your understanding of ISO8583 bitmap structure, bit numbering, secondary bitmaps, and bitmap manipulation.

Get every question correct to pass this checkpoint. You can review feedback, revise your answers, and submit again.

1. In an ISO8583 primary bitmap, which bit indicates that a secondary bitmap follows?

Select one answer.

Bit 64 Bit 1 Bit 65 Bit 0

2. You see a primary bitmap starting with byte `0x72`. Which fields from 1-8 are present?

Select one answer.

Fields 1, 2, 7 Fields 2, 3, 6, 7 Fields 2, 3, 4, 7 Fields 1, 3, 4, 7

3. What is Field 1 (DE1) in ISO8583?

Select one answer.

Reserved for future use The message length header The secondary bitmap (when present) The primary bitmap

4. To check if field 11 is present, you calculate byteIndex = (11-1)/8 = 1 and bitPosition = 7 - ((11-1)%8) = 5. What does this mean?

Select one answer.

Check bit 11 of byte 1 Check bit 5 of byte 1 Check bit 5 of byte 0 Check bit 1 of byte 5

5. A binary-bitmap profile supports fields through 128. A message includes fields 2,3,4,70. What bitmap is required?

Select one answer.

Three bitmaps because 70 is above 64 One 8-byte bitmap with no extension bit Exactly 16 ASCII characters Two 8-byte bitmaps with the primary extension bit set

6. A bitmap shows the hex bytes `80 00 00 00 00 00 00 00`. Which field is present?

Select one answer.

No fields are present Field 1 (secondary bitmap indicator) Field 0 Field 8

7. What's the difference between binary and hex-ASCII bitmap encoding?

Select one answer.

Binary uses 16 bytes, hex-ASCII uses 8 bytes Binary is for 1987 spec, hex-ASCII is for 2003 spec Binary uses 8 raw bytes, hex-ASCII uses 16 ASCII characters representing the hex They are the same thing

8. You're debugging a parser that shows field 64 when it should show field 65. What's the likely bug?

Select one answer.

Off-by-one error: using 0-based instead of 1-based field numbering Endianness issue with the bitmap bytes The secondary bitmap is missing The bitmap is hex-ASCII encoded

9. In the formula `bitPosition = 7 - ((field - 1) % 8)`, why do we subtract from 7?

Select one answer.

To account for the secondary bitmap indicator Because ISO8583 uses MSB-first bit ordering within each byte Because there are 7 bytes in a bitmap Because field numbers max out at 7

10. A binary-bitmap parser reads primary byte 0x40 followed by seven zero bytes. What should it do next?

Select one answer.

Read a secondary bitmap because DE2 is present Parse DE2; do not consume a secondary bitmap Assume field 65 is set Treat all remaining bytes as bitmap

11. In a zero-indexed byte array with MSB-first field numbering, how is field 37 set?

Select one answer.

bitmap[5] |= 0x08 bitmap[4] |= 0x10 bitmap[3] |= 0x04 bitmap[4] |= 0x08

12. The partner specifies hex-ASCII bitmap encoding. The first eight wire bytes are 37 32 33 41 34 34 38 31. What representation is being received?

Select one answer.

The partner is using 2003 spec with tertiary bitmap The partner is sending hex-ASCII encoded bitmaps The bitmap is corrupted The byte order is reversed

13. A configured profile explicitly supports a third bitmap. What additional field range can it represent?

Select one answer.

129 through 192 Every field without any upper bound 65 through 128 1 through 64 only

14. A message fails with 'unexpected end of message'. The bitmap indicated 15 fields but only 14 were found. What likely happened?

Select one answer.

The parser has a bug in field counting A field was omitted from the data without clearing its bitmap bit The bitmap has a bit set that shouldn't be Any of the above could cause this error

15. Which pair necessarily needs secondary-bitmap positions in a two-bitmap profile?

Select one answer.

DE90 and DE128 DE48 and DE63 DE2 and DE64 DE11 and DE37

Auto-advance on pass

Join Discord