Convert single line RSA private ssh key to multi line

encryption ssh openssl rsa

15,353

Solution 1

Assuming a standard RSA private key that just had the newlines removed, a couple of sed replacements will get you back to the original format:

sed -e "s/-----BEGIN RSA PRIVATE KEY-----/&\n/"\
    -e "s/-----END RSA PRIVATE KEY-----/\n&/"\
    -e "s/\S\{64\}/&\n/g"\
    ~/.ssh/id_rsa

The standard key format requires the BEGIN and END statements to be on a separate line, and the base64-encoded key to be formatted at 64 columns. The above command will get you there.

Solution 2

@robby Thanks from your answer I adapted the following which worked for me.

sed -e "s/-----BEGIN RSA PRIVATE KEY-----/&\n/" -e "s/\S\{64\}/&\n/g" | sed "s/^\s//g" ~/.ssh/id_rsa

Solution 3

I adapted the solution to ed25519 algorithm to talk to Gitlab via SSH. Thanks @Robby!

RUN sed -i -e "s/-----BEGIN OPENSSH PRIVATE KEY-----/&\n/"\
    -e "s/-----END OPENSSH PRIVATE KEY-----/\n&/"\
    -e "s/\S\{70\}/&\n/g"\
    /root/.ssh/id_ed25519

Input

Output

15,353

Author by

Ikenna

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Updated on July 22, 2022

Comments

Ikenna almost 2 years

I have these private keys that have been converted to single line equivalent.

These keys are quite a lot.

So I decided to invest some time to write a script to convert.

This has not yielded to much.

-----BEGIN RSA PRIVATE KEY----pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4= pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4= pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4= pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4= pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4= -----END RSA PRIVATE KEY-----

I am using echo ~/.ssh/id_rsa | tr " " "\n"

This returns:

-----BEGIN 
RSA 
PRIVATE 
KEY----- 
pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=
pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=
pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=
pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=
pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=pEdInVAbH4d0PH4=
-----END
RSA
PRIVATE
KEY-----

I have been trying to figure out the best possible way to get this back to the right format.

roy over 4 years

I tried this on Ubuntu and worked. But not on MacBook
RubenLaguna almost 4 years

you need to install GNU sed in mac with for example brew install gnu-sed and then use gsed instead of sed
Robby Cornelissen almost 3 years

@WilliamRoss Best guess: you don't have the same begin stanza as the one in my code (-----BEGIN RSA PRIVATE KEY-----). Maybe yours has BEGIN EC PRIVATE KEY or BEGIN PRIVATE KEY. Or maybe you deleted a hyphen by accident at some point...
Robby Cornelissen almost 3 years

@WilliamRoss Is removing your comment your way of indicating that my guess was correct, and your issue is solved?