MD5 is 128 bits but why is it 32 characters

Question

I read some docs about md5  it said that its 128 bits  but why is it 32 characters  I can t compute the characters    1 byte is 8 bits if 1 character is 1 byte then 128 bits is 128 8   16 bytes right    EDIT   SHA-1 produces 160 bits  so how many characters are there

User · Accepted Answer

32 chars as hexdecimal representation  thats 2 chars per byte

User · Answer

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

User · Answer

They re not actually characters  they re hexadecimal digits

User · Answer

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

User · Answer

Those are hexidecimal digits  not characters  One digit   4 bits

User · Answer

A hex  character   nibble  is different from a  character   To be clear on the bits vs byte  vs characters    1 byte is 8 bits  for our purposes  8 bits provides 2  8 possible combinations  256 combinations   When you look at a hex character    16 combinations of  0-9     a-f   the full range of 0 1 2 3 4 5 6 7 8 9 a b c d e f 16 is less than 256  so one one hex character does not store a byte  16 is 2  4  that means one hex character can store 4 bits in a byte  half a byte   Therefore  two hex characters  can store 8 bits  2  8 combinations  A byte represented as a hex character is  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    It can store far more than 16 combinations  The capabilities of the character are determined by the encoding  For instance  the ISO 8859-1 that stores an entire byte  stores all this stuff All that stuff takes the entire 2  8 range  If a hex-character in an md5   could store all that  you d see all the lowercase letters  all the uppercase letters  all the punctuation and things like               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

User · Answer

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

User · Answer

That s 32 hex characters - 1 hex character is 4 bits

[hash] MD5 is 128 bits but why is it 32 characters?

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