I read some docs about md5, it said that its 128 bits, but why is it 32 characters? I can't compute the characters.
EDIT:
SHA-1 produces 160 bits, so how many characters are there?
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32 chars as hexdecimal representation, thats 2 chars per byte.
To be clear on the bits vs byte, vs characters.
2**8
possible combinations: 256 combinationsWhen you look at a hex character,
[0-9] + [a-f]
: the full range of 0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f
2**4
: that means one hex character can store 4 bits in a byte (half a byte).2**8
combinations.[0-9a-f][0-9a-f]
and that represents both halfs of a byte (we call a half-byte a nibble).When you look at a regular single-byte character, (we're totally going to skip multi-byte and wide-characters here)
2**8
range.md5()
could store all that, you'd see all the lowercase letters, all the uppercase letters, all the punctuation and things like ¡°ÀÐàð
, whitespace like (newlines, and tabs), and control characters (which you can't even see and many of which aren't in use).So they're clearly different and I hope that provides the best break down of the differences.
One hex digit = 1 nibble (four-bits)
Two hex digits = 1 byte (eight-bits)
MD5 = 32 hex digits
32 hex digits = 16 bytes ( 32 / 2)
16 bytes = 128 bits (16 * 8)
The same applies to SHA-1 except it's 40 hex digits long.
I hope this helps.
That's 32 hex characters - 1 hex character is 4 bits.
I wanted summerize some of the answers into one post.
First, don't think of the MD5 hash as a character string but as a hex number. Therefore, each digit is a hex digit (0-15 or 0-F) and represents four bits, not eight.
Taking that further, one byte or eight bits are represented by two hex digits, e.g. b'1111 1111
' = 0xFF
= 255
.
MD5 hashes are 128 bits in length and generally represented by 32 hex digits.
SHA-1 hashes are 160 bits in length and generally represented by 40 hex digits.
For the SHA-2 family, I think the hash length can be one of a pre-determined set. So SHA-512 can be represented by 128 hex digits.
Again, this post is just based on previous answers.
Those are hexidecimal digits, not characters. One digit = 4 bits.
They're not actually characters, they're hexadecimal digits.
MD5 yields hexadecimal digits (0-15 / 0-F), so they are four bits each. 128 / 4 = 32 characters.
SHA-1 yields hexadecimal digits too (0-15 / 0-F), so 160 / 4 = 40 characters.
(Since they're mathematical operations, most hashing functions' output is commonly represented as hex digits.)
You were probably thinking of ASCII text characters, which are 8 bits.
Source: Stackoverflow.com