An MD5 is a type of Hash, also, a Checksum.<\/p>\n
An MD5 hash is a one way verification sum which can be used to verify a string or contents of a file. Once you have a file and an MD5 checksum, the recipient of the file can also perform an MD5 calculation to ensure that the file\u2019s contents are unchanged. They may have been changed maliciously such as in the case of a binary file, or simply by data corruption. An MD5 is NOT a type of encryption. It can not be reversed.
\nWe can use PHP to do the following:<\/p>\n
< ?php\n$string = \u201cteststring\u201d;\n$checksum = md5($string);\necho \u201cThe checksum is: \u201d . $checksum . \u201c\\n\u201d;\n?><\/p>\n
The output is:<\/p>\n
The checksum is: d67c5cbf5b01c9f91932e3b8def5e5f8<\/p>\n
We can use the \u2018md5sum\u2019 linux command and pipe input to it via STDIN.<\/p>\n
echo \u201cteststring\u201d|md5sum<\/p>\n
test:~# echo \u201cteststring\u201d|md5sum
\n50be80a7a199c13e2bb09e2e745ba233 –<\/p>\n
Why is the output of this md5sum different to that above? Well, \u2018echo\u2019 automatically adds a newline to the string to make it \u201cteststring\\n\u201d. We can surpress this with -n:<\/p>\n
test:~# echo -n \u201cteststring\u201d|md5sum
\nd67c5cbf5b01c9f91932e3b8def5e5f8 –<\/p>\n
We can also run the md5sum command against a file:<\/p>\n
test:~# md5sum \/bin\/bash
\nc8770eb0a3f2b6088914b4bc29301113 \/bin\/bash<\/p>\n","protected":false},"excerpt":{"rendered":"
An MD5 is a type of Hash, also, a Checksum. An MD5 hash is a one way verification sum which can be used to verify a string or contents of a file. Once you have a file and an MD5 checksum, the recipient of the file can also perform an MD5 calculation to ensure that… <\/p>\n