Recovering an old Multibit wallet file (76 characters long) I have a wallet file from 2011 back when I used to play around with Bitcoin.
I used an old version of Multibit which has since long been unavailable.
My wallet looks like this:
# KEEP YOUR PRIVATE KEYS SAFE !
# Anyone who can read this file can spend your bitcoin.
#
# Format:
#   &lt;Base58 encoded private key&gt;[&lt;whitespace&gt;[&lt;key createdAt&gt;]]
#
#   The Base58 encoded private keys are the same format as
#   produced by the Satoshi client/ sipa dumpprivkey utility.
#
#   Key createdAt is in UTC format as specified by ISO 8601
#   e.g: 2011-12-31T16:42:00Z . The century, 'T' and 'Z' are mandatory
#
U2FsdGVXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXsnQhpZ6
 2013-10-30T20:52:01Z
# End of private keys

I managed to get a version of Multibit HD from the web archive but this doesn't support this wallet.
I also tried using OpenSSL with the following command:
openssl enc -d -p -aes-256-cbc -md md5 -a -in C:\key\wallet.key.txt -out c:\key\wallet-decrypted.key.txt

This output a file which wasn't correct and gave a bad decrypt error. I know the password for this file.
Does anyone know the correct method of decrypting this?
UPDATE: While I'm at it, I found a whole bunch more .key files. This one has a different format:
org.bitcoin.productionm!œ;€ò=°´zXXXXXXXXXXXXXXXXXÌñ9,o( 2D
ä¢¦]5+¡XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXE}Û@nŸé(2

ÐáXXXXR#
org.multibit.walletProtect.2 ZYour wallet description`
Does anyone know the correct method of decrypting this?

It doesn't seem to be encrypted. The comments at the start of the file don't mention any form of encryption. It only mentions a common form of encoding - Base58. Encoding is not encryption so no decryption is needed.


#   The Base58 encoded private keys are the same format as
#   produced by the Satoshi client/ sipa dumpprivkey utility.


That Base58 key ought to be able to be imported into several different modern wallet programs.
See

Private keys importing in format got by dumpprivkey
How to get the private key in hex from the output of dumpprivkey
https://btcinformation.org/en/developer-reference#dumpprivkey