Why do these base64 encoding outputs differ, given the same input string?

Question

When getting a bas64 encoded string from the same input string I find that JavaScript, Groovy, and Go have the same result, but GNU base64 is slightly different. Why is that?

JavaScript (nodejs v0.10.33):

new Buffer('Laurence Tureaud is Mr. T').toString('base64');
TGF1cmVuY2UgVHVyZWF1ZCBpcyBNci4gVA==

Groovy (2.3.7 on Java 8):

'Laurence Tureaud is Mr. T'.bytes.encodeBase64().toString()
TGF1cmVuY2UgVHVyZWF1ZCBpcyBNci4gVA==

Go (1.4):

b64.StdEncoding.EncodeToString([]byte("Laurence Tureaud is Mr. T"))
TGF1cmVuY2UgVHVyZWF1ZCBpcyBNci4gVA==

GNU base64 (GNU coreutils 8.12.197-032bb with UTF-8 term charset):

echo 'Laurence Tureaud is Mr. T' | base64
TGF1cmVuY2UgVHVyZWF1ZCBpcyBNci4gVAo=

If you decode the results you'll see that the GNU base64 has a new line character at the end. (You get 'Laurence Tureaud is Mr. T\n' where \n is a new line. — Daniel Tung
– Daniel Tung, Commented May 7, 2015 at 13:32

Daniel Tung · Accepted Answer · 2015-05-07 13:40:25Z

8

echo 'Laurence Tureaud is Mr. T'

Echo adds a newline after the string.

Try the following to remove the newline:

echo -n 'Laurence Tureaud is Mr. T' | base64

And you get TGF1cmVuY2UgVHVyZWF1ZCBpcyBNci4gVA==

edited May 7, 2015 at 13:40

Daniel Tung

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answered May 7, 2015 at 13:31

Roger Gustavsson

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4 Comments

user605331 Over a year ago

Ah, yes, that was it indeed. The following matches: printf 'Laurence Tureaud is Mr. T' | base64

Daniel Tung Over a year ago

@user605331 If this worked for you, please mark this as the correct solution. Thanks! :)

user605331 Over a year ago

SO won't allow until 5 minutes has passed. I tried.

Daniel Tung Over a year ago

@user605331 Sorry, didn't mean to rush you. Just wanted to put a little reminder. I added a little more to this answer for future reference!

Uwe Plonus · Accepted Answer · 2015-05-07 13:32:33Z

4

All output is the same.

The only difference is that bash appends a newline (\n) to the end when using echo. Therefore the is an additional character appended to the output (the character = is only a padding in base64).

answered May 7, 2015 at 13:32

Uwe Plonus

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