When searching file headers for JPEG formats in hex, which sequence indicates a JPEG header?

When searching file headers for JPEG formats in hex, which sequence indicates a JPEG header?

• A. FF D8 FF E0 00 10
• B. FF FF FF FF FF FF
• C. FF 00 FF 00 FF 00
• D. EF 00 EF 00 EF 00

Answer: (A)

JPEG files start with a Start of Image marker, followed by a marker for the application segment (usually APP0 for JFIF). The sequence begins with 0xFFD8 (SOI), then 0xFFE0 (APP0), then a two-byte length, commonly 0x0010, and the ASCII "JFIF". So the pattern FFD8 FF E0 00 10 matches this typical header, making it a reliable indicator of a JPEG header in hex data. The other sequences don’t form a valid JPEG header: a string of 0xFF bytes has no marker type; 0xFF 00 is not a marker sequence but a byte-stuffing pattern seen inside streams; 0xEF 00 EF 00 EF 00 isn’t a recognized JPEG marker pattern.

JPEG files start with a Start of Image marker, followed by a marker for the application segment (usually APP0 for JFIF). The sequence begins with 0xFFD8 (SOI), then 0xFFE0 (APP0), then a two-byte length, commonly 0x0010, and the ASCII "JFIF". So the pattern FFD8 FF E0 00 10 matches this typical header, making it a reliable indicator of a JPEG header in hex data.

The other sequences don’t form a valid JPEG header: a string of 0xFF bytes has no marker type; 0xFF 00 is not a marker sequence but a byte-stuffing pattern seen inside streams; 0xEF 00 EF 00 EF 00 isn’t a recognized JPEG marker pattern.