Skip to content

Instantly share code, notes, and snippets.

@yidas

yidas/public-key-fingerprint-formula.md

Last active August 22, 2019 08:54
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save yidas/32bdfb36ab8279497ae4a34d01e5e27b to your computer and use it in GitHub Desktop.
Save yidas/32bdfb36ab8279497ae4a34d01e5e27b to your computer and use it in GitHub Desktop.
Download ZIP
Public key's fingerprint formula
Raw
public-key-fingerprint-formula.md

Public key's fingerprint formula

The public key file (key.pub) contains the binary key that is packaged into a base64 string.

Formula

The public key's fingerprint formula:

# SHA256
Base64Encode( SHA256( Base64Decode( base64-key-string ) ) )

# MD5
MD5-HEX( Base64Decode( base64-key-string ) )

PHP sameple:

$publicKeyContent = "AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBPMYhoA2ICw6rVutJ9CaF63NCUwE3KCB06JjScoVIfOQilV7y/s6I7ty765jaVXo8Thj8ePVwy6whivI8NbZ8UY=";

$fingerPrint = base64_encode(hash('sha256', base64_decode($publicKeyContent), true));

// MD5
$fingerPrintMD5 = md5(base64_decode($publicKeyContent));

The $fingerPrint should same as the fingerprint in SSH connection: Server host key: ecdsa-sha2-nistp256 SHA256:AcrTsZ7KfsKzak2d68qCJKdXrZ+9TOhfr0/J3BMAa8U

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment