问题
I am quite confused as to why I am seeing different results for md5 hashing in PHP and in OpenSSL.
Here is the code that I am running:
php -r "echo md5('abc');"
Results in: 900150983cd24fb0d6963f7d28e17f72
While this:
echo abc | openssl md5
Results in: 0bee89b07a248e27c83fc3d5951213c1
Why?
回答1:
There is only one way to compute MD5.
A blind guess is that the second one also includes a newline inside the string being hashed.
Yeh, verified it. That's it.
回答2:
As everyone noted, the problem is that echo prints an extra newline.
However, the solution proposed (echo -n) is not completely correct. According to the POSIX standard, "Implementations shall not support any options." You'll make the world a bit better if you don't use it.
Use
printf %s abc | openssl md5
or simply
printf abc | openssl md5
回答3:
echo normally adds a new line character at the end of the string it outputs; that is the reason the MD5 values are different.
Try with echo -n abc | openssl md5.
回答4:
As jdehaan notes, if you tell echo not output a newline, you get the answer you expect
echo -n "abc" | openssl md5
900150983cd24fb0d6963f7d28e17f72
来源：https://stackoverflow.com/questions/3169605/why-phps-md5-is-different-from-openssls-md5