Hex encoding - Revision history

Jsummers at 13:14, 17 October 2015

2015-10-17T13:14:31Z

Dan Tobias at 01:17, 29 August 2014

2014-08-29T01:17:36Z

Jsummers at 00:58, 29 August 2014

2014-08-29T00:58:50Z

Jsummers at 00:53, 29 August 2014

2014-08-29T00:53:04Z

Jsummers: Created page with "{{FormatInfo |formattype=electronic |subcat=Transfer Encodings }} '''Hex encoding''' is a transfer encoding in which each byte is converted to the 2-digit base-16 encoding of ..."

2014-08-29T00:40:58Z

Created page with "{{FormatInfo |formattype=electronic |subcat=Transfer Encodings }} '''Hex encoding''' is a transfer encoding in which each byte is converted to the 2-digit base-16 encoding of ..."

New page

{{FormatInfo
|formattype=electronic
|subcat=Transfer Encodings
}}
'''Hex encoding''' is a transfer encoding in which each byte is converted to the 2-digit base-16 encoding of that byte (preserving leading zeroes), which is then usually encoded in [[ASCII]]. It is inefficient, but it is a simple, commonly-used way to represent binary data in plain text.

It is not a formal standard, so the term ''hex encoding'' may have other meanings, and the format described in the article may have other names.

Most hex encoders use uppercase letters ("A" through "F"), but lowercase ("a" through "f") is not uncommon, and hex decoders typically support both.

The most significant hex digit almost always comes first, but variants in which the least significant digit comes first do exist.

The distinction between hex encoding and ''base-16'' (hexadecimal) is not always clear. If you interpret a datastream as a single (probably huge) number, and write that number in base-16, it can, with suitable conventions, be equivalent to hex encoding. For example, consider the way that [[Encryption|cryptographic hashes]] are usually written.

== Examples ==
The hex encoding of the ASCII string "<code>hijkl</code>", followed by a newline character ("<code>\n</code>"), is "<code>68696A6B6C0A</code>".

A [[perl]] one-liner to do hex encoding:
perl -ne 'print uc(unpack("H*",$_))' original.bin > encoded.txt

And decoding:
perl -ne 'print pack("H*",$_)' encoded.txt > decoded.bin

== Links ==
* [http://tenminutetutor.com/hex-base16-encoding Ten Minute Tutor: Hex (Base16) encoding]
* [http://www.convertstring.com/EncodeDecode/HexEncode Online Hex Encoder]
* [http://www.convertstring.com/EncodeDecode/HexDecode Online Hex Decoder]
* RFC 4648: The Base16, Base32, and Base64 Data Encodings
* RFC 3548: The Base16, Base32, and Base64 Data Encodings (obsolete)

@@ Line 7: / Line 7: @@
 It is not a formal standard, so the term ''hex encoding'' may have other meanings, and the format described in the article may have other names.
-Most hex encoders use uppercase letters ("A" through "F"), but lowercase ("a" through "f") is not uncommon, and hex decoders typically support both. Whitespace characters may be allowed, and ignored.
+Both uppercase ("A" through "F") and lowercase ("a" through "f") letters are common, and hex decoders typically support both. Whitespace characters may be allowed, and ignored. Other characters that aren't hex digits might be used for special purposes.
 The most significant hex digit almost always [[Bit order|comes first]], but variants in which the least significant digit comes first do exist, for example [[ASCII Encoded HP 48 Object]].
-The distinction between hex encoding and ''base-16'' (hexadecimal) is not always clear. If you interpret a datastream as a single (probably huge) number, and write that number in base-16, it can, with suitable conventions, be equivalent to hex encoding. For example, consider the way that [[Encryption|cryptographic hashes]] are usually written.
+The distinction between ''hex encoding'' and ''base-16'' (hexadecimal) is not always clear. If you interpret a datastream as a single (probably huge) number, and write that number in base-16, it can, with suitable conventions, be equivalent to hex encoding. For example, consider the way that [[Encryption|cryptographic hashes]] are usually written.
 The earliest versions of [[BinHex]] used a form of hex encoding, but the program later evolved to a different encoding based on base 64 instead of base 16 (similar to [[Base64]] encoding but with a different set of characters).
 == Examples ==
-The hex encoding of the ASCII string "<code>hijkl</code>", followed by a newline character ("<code>\n</code>"), is "<code>68696A6B6C0A</code>".
+<code>xxd</code> is a widely-installed Unix utility that can do hex encoding and decoding.
-A [[perl]] one-liner to do hex encoding:
+  $ echo "Hex encoding test" | xxd -p
-  perl -ne 'print uc(unpack("H*",$_))' original.bin &gt; encoded.txt
+ 48657820656e636f64696e6720746573740a
-And decoding:
+  $ echo "48657820656e636f64696e6720746573740a" | xxd -r -p
-  perl -ne 'print pack("H*",$_)' encoded.txt &gt; decoded.bin
+ Hex encoding test
 == Links ==

← Older revision		Revision as of 01:17, 29 August 2014
Line 12:		Line 12:

	The distinction between hex encoding and ''base-16'' (hexadecimal) is not always clear. If you interpret a datastream as a single (probably huge) number, and write that number in base-16, it can, with suitable conventions, be equivalent to hex encoding. For example, consider the way that [[Encryption\|cryptographic hashes]] are usually written.		The distinction between hex encoding and ''base-16'' (hexadecimal) is not always clear. If you interpret a datastream as a single (probably huge) number, and write that number in base-16, it can, with suitable conventions, be equivalent to hex encoding. For example, consider the way that [[Encryption\|cryptographic hashes]] are usually written.
		+
		+	The earliest versions of [[BinHex]] used a form of hex encoding, but the program later evolved to a different encoding based on base 64 instead of base 16 (similar to [[Base64]] encoding but with a different set of characters).

	== Examples ==		== Examples ==

@@ Line 7: / Line 7: @@
 It is not a formal standard, so the term ''hex encoding'' may have other meanings, and the format described in the article may have other names.
-Most hex encoders use uppercase letters ("A" through "F"), but lowercase ("a" through "f") is not uncommon, and hex decoders typically support both.
+Most hex encoders use uppercase letters ("A" through "F"), but lowercase ("a" through "f") is not uncommon, and hex decoders typically support both. Whitespace characters may be allowed, and ignored.
-The most significant hex digit almost always [[Bit order|comes first]], but variants in which the least significant digit comes first do exist, such as [[ASCII Encoded HP 48 Object]].
+The most significant hex digit almost always [[Bit order|comes first]], but variants in which the least significant digit comes first do exist, for example [[ASCII Encoded HP 48 Object]].
 The distinction between hex encoding and ''base-16'' (hexadecimal) is not always clear. If you interpret a datastream as a single (probably huge) number, and write that number in base-16, it can, with suitable conventions, be equivalent to hex encoding. For example, consider the way that [[Encryption|cryptographic hashes]] are usually written.