# What is the key\_file's format

**URL:** <https://community.blockcerts.org/t/what-is-the-key-files-format/2241>\
**Category:** Support\
**Created:** [December 26, 2019, 5:47am UTC](https://community.blockcerts.org/t/what-is-the-key-files-format/2241 "2019-12-26T05:47:59Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![LuckyLQD](https://avatars.discourse-cdn.com/v4/letter/l/a6a055/32.png) [@LuckyLQD](https://community.blockcerts.org/u/LuckyLQD)\
**Post date:** [December 26, 2019, 5:47am UTC](https://community.blockcerts.org/t/what-is-the-key-files-format/2241/1 "2019-12-26T05:47:59Z")

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Hello, I have a question that, in the cert-issuer, the key\_file = .  
What is the format of the file? Should it contains “ecdsa-koblitz-pubkey:”? Could you give me an example? Thank you.

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**Author:** ![aronning](https://avatars.discourse-cdn.com/v4/letter/a/47e85d/32.png) [@aronning](https://community.blockcerts.org/u/aronning)\
**Post date:** [January 6, 2020, 3:11pm UTC](https://community.blockcerts.org/t/what-is-the-key-files-format/2241/2 "2020-01-06T15:11:33Z")

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Text file is fine, and no, it should just be the private key WIF as it is. No appending anything to it.

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**Author:** ![arycloud](https://avatars.discourse-cdn.com/v4/letter/a/85f322/32.png) [@arycloud](https://community.blockcerts.org/u/arycloud)\
**Post date:** [February 20, 2020, 9:13am UTC](https://community.blockcerts.org/t/what-is-the-key-files-format/2241/3 "2020-02-20T09:13:54Z")

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I have pasted the WIF private key in `key.txt` file but when I run the command as `cert-issuer -c conf.ini` I got an error as:  
`pycoin.encoding.EncodingError: unexpected first byte of WIF `  
help me, please!