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Project Notes

php md5

Are you still using MD5 in PHP!?

Notes

MD5 is a cryptographically broken but still used for hashing.

PHP has an md5 string function

Example

See to_md5.php - a simple wrapper for the md5 function:

$ php to_md5.php QNKCDZO QNKCDZO as md5: 0e830400451993494058024219903391

MD5 Comparisons

Always use triple equals ===. Why? …

$ php example.php
240610708 as md5: 0e462097431906509019562988736854
QNKCDZO as md5: 0e830400451993494058024219903391
md5(240610708) == md5(QNKCDZO) : true (!!!)
  -> This comparison is true because both md5() hashes start '0e' so PHP type juggling understands these strings to be scientific notation.  By definition, zero raised to any power is zero.
md5(240610708) === md5(QNKCDZO) : false
  -> always use the triple equals === for comparing stirng values to avoid all the quirks and pitfalls.

Credits and References

  • MD5 wikipedia
  • md5 - PHP function reference
About LCK#237 php
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