The Salesforce crypto class documentation specifies that a private key should be stored as a protected custom setting.
"A PKCS8 formatted private key in base64 decoded form is required. This private key should not be hardcoded in the Apex script but should be stored in a protected custom setting or a encrypted fields in a custom table"
https://developer.salesforce.com/page/Apex_Crypto_Class
How do I do this because it seems that custom setting field values are limited to 255 characters?
Thanks