Hex Encode & Decode

A: Hex and Base64 are both text representations of binary data, but have different characteristics. Hex: 1) Uses 16 characters (0-9, A-F). 2) Encoded size is 200% of original data. 3) More readable, suitable for debugging. Base64: 1) Uses 64 characters (A-Z, a-z, 0-9, +, /). 2) Encoded size is approximately 133% of original data. 3) More compact, suitable for transmission. Selection Advice: 1) Need readability and debugging: use Hex. 2) Need compact transmission: use Base64. 3) Encryption algorithm output: typically uses Hex (such as SHA-256).

A: Hash algorithms (such as SHA-256, MD5) output binary data, typically represented in Hex. Reasons: 1) Readability: Hex is more readable than binary, easy for manual comparison. 2) Fixed Length: SHA-256 outputs 32 bytes, represented as 64 Hex characters with fixed length. 3) Traditional Practice: Encryption and hashing fields traditionally use Hex. 4) Debugging-Friendly: Developers can easily copy, paste, and compare hash values. Example: SHA-256(“hello”) = 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824.

A: Hex color codes represent RGB colors using hexadecimal notation, formatted as #RRGGBB. Format: 1) #RRGGBB: 6-digit hexadecimal, each 2 digits represent a color channel (red, green, blue). 2) #RGB: 3-digit shorthand, each digit repeated once (e.g., #F00 = #FF0000). Examples: 1) #FF0000: Pure red (R=255, G=0, B=0). 2) #00FF00: Pure green (R=0, G=255, B=0). 3) #0000FF: Pure blue (R=0, G=0, B=255). 4) #FFFFFF: White. 5) #000000: Black. Conversion: Hex colors can be converted to RGB (e.g., rgb(255, 87, 51)) or HSL (e.g., hsl(14, 100%, 60%)).

A: MAC addresses (Media Access Control Address) are physical addresses of network devices, represented in Hex. Format: 6 bytes (48 bits), typically separated by colons or hyphens, such as 00:1A:2B:3C:4D:5E or 00-1A-2B-3C-4D-5E. Reasons: 1) Compact: 6 bytes represented by 12 hexadecimal characters, more compact than binary (48 bits) or decimal (14-digit number). 2) Readable: Hex is more readable than binary, easy for manual identification and input. 3) Standard: IEEE 802 standard specifies using Hex to represent MAC addresses. Example: 00:1A:2B:3C:4D:5E represents MAC address 0x001A2B3C4D5E.

A: JavaScript provides multiple methods for handling Hex encoding. String to Hex:
const str = 'Hello'; const hex = Array.from(str).map(c => c.charCodeAt(0).toString(16).padStart(2, '0')).join(''); // Result: '48656c6c6f'
Hex to String:
const hex = '48656c6c6f'; const str = hex.match(/.{1,2}/g).map(byte => String.fromCharCode(parseInt(byte, 16))).join(''); // Result: 'Hello'
Number to Hex: const hex = (255).toString(16); // 'ff'
Hex to Number: const num = parseInt('ff', 16); // 255

A: A Hex editor is a tool for viewing and editing binary files, displaying file contents in hexadecimal format. Features: 1) View Binary Files: Display each byte of a file in Hex format. 2) Edit Binary Files: Directly modify byte values in files. 3) Search and Replace: Search for specific byte sequences in binary files. 4) File Analysis: Analyze file structure, find file headers, identify file types. Use Cases: 1) Reverse engineering: Analyze executables, firmware. 2) Data recovery: Repair corrupted files. 3) Game modification: Modify game saves, configurations. 4) Security research: Analyze malware. Common Tools: HxD (Windows), Hex Fiend (macOS), xxd (Linux command line).