![]() ![]() It's also possible to use the base64 command to decode a string: base64 -d <<< a3J5cHRlZAo= So to then decode this string, we can use the following command: openssl enc -base64 -d <<< a3J5cHRlZAo= The <<< is a "here-string" that simulates text entry. In the above command, we used the enc verb with the -base64 option. We’ll use the openssl command to do this: openssl enc -base64 <<< krypted Let’s start with a quick example of encoding a string object into base64. Thus, time to bust out the old openssl and base64 commands. The machine was offline, so I couldn’t use one of the many online decoders to see what it was doing. ![]() One thing that jumped out at me was that the payload was a bunch of base64 encoded blobs. Like with a lot of phishing-types of emails, it was really just trying to get at a password (in this case it was a fake Office365 login). We have gone through all use cases of options available in the base64 command.I received a piece of malware today and as one will do, I of course opened it up on my test machine. It is used to Base64 encode or decode data provided as input. In this article, we explored a basic Linux command base64. You found the super secret base64 content. To remove this error we need to ignore non-alphabet characters as follows: $ echo -e `cat file2.txt` "\r\n" | base64 -d -i You can see that it gives errors while dealing with non-alphabet characters. $ echo -e `cat file2.txt` "\r\n" | base64 -d Now use this mixture of Base64 encoded text and non-alphabet characters and try to decode it with the help of the base64 -d command. WW91IGZvdW5kIHRoZSBzdXBlciBzZWNyZXQgYmFzZTY0IGNvbnRlbnQuIFNlZSB5b3UgaW4gdGhl IG5leHQgZXhhbXBsZQo= Let’s again use the Base64 encoded file from example 2 and add some non alphabet characters with the help of the echo command. Ignore non-alphabet characters provided in input. You can disable line wrapping by using COLS equal to 0. (Default COLS is 76) base64 -w COLS filename Line wrapping of Base64 encoded output of the base64 command. $ cat file2.txtĪgain use the standard output of cat command as standard input for base64 command. Let’s use the content of the file from example 2. Decode Base64 encoded text with the base64 command. ZXhhbXBsZTM6CnBpcGVzIGFyZSBhbWF6aW5nIGJlY2F1c2Ugd2UgY2FuIGRlY2lkZSB3aGVyZQoK $ echo -e "example3:\npipes are amazing because we can decide where\n\n input and output goes" | base64 Use | to use echo command’s output as input for base64. Pipes are amazing because we can decide where $ echo -e "example3:\npipes are amazing because we can decide where\n\n input and output goes" Let’s use the echo command’s output for this example. Base64 encodes the data provided through standard input with base64 command. Let’s run the base64 command with the -d option to decode the contents of the file provided as an argument. ![]() WW91IGZvdW5kIHRoZSBzdXBlciBzZWNyZXQgYmFzZTY0IGNvbnRlbnQuIFNlZSB5b3UgaW4gdGhl We have a file with some Base64 encoded text in it. Decode a file containing Base64 content and write the result to stdout: base64 -decode filename V2VsY29tZSB0byB0dXRvcmlhbHNwb2ludC5jb20KVGhpcyBpcyBhbiBhcnRpY2xlIGFib3V0IHRo Let’s run the base64 command with the file name as argument: $ base64 file1.txt This is an article about the base64 command. Here, we have a file named file1.txt: $ cat file1.txt Base64 encodes a file’s content provided as an argument and write the result to standard output: $ base64 filename Use 0 to disable line wrapping.Įxamples of base64 command: 1. Wrap encoded lines after the COLS character (default 76). When decoding, ignore non-alphabet characters provided as input. base64 command options -d, -decodeĭecode base64 data provided as input and print to standard output. Use -ignore-garbage to attempt to recover from any other non-alphabet bytes in the encoded stream. ![]() Mandatory arguments to long options are mandatory for short options too. When decoding, the input may contain newlines in addition to the bytes of the formal base64 alphabet. You can provide a file name as an argument, otherwise it will read standard input. Base64 is a collection of binary-to-text encoding techniques that can convert sequences of 8-bit bytes, which make up binary data, into sequences of 24 bits, which can be represented by four 6-bit Base64 digits. On Unix-like operating systems, the base64 command is used for the base64 encoding scheme the base64 command converts binary strings into text representations. ![]()
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