The use of md5 and sha1, base64

md5

[root@localhost shell]# md5sum text.txt > text.txt.md5
[root@localhost shell]# cat text.txt.md5
fe60c3cfe9414423c736dcc3e6c6d869  text.txt
[root@localhost shell]# md5sum -c text.txt.md5
text.txt: OK

sha1

[root@localhost shell]# sha1sum text.txt > text.txt.sha1
[root@localhost shell]# cat text.txt.sha1
2d7bc09c938d40e396db72fb9739979a5fc24542  text.txt
[root@localhost shell]# sha1sum -c text.txt.sha1
text.txt: OK

sh5 and sha1 are irreversible
base64

[root@localhost shell]# base64 text.txt > text.txt.base64
[root@localhost shell]# cat text.txt.base64
YWEKc2RmYQo =
[root@localhost shell]# base64 -d text.txt.base64
aa
sdfa