http://www.rfc-editor.org/rfc/rfc5915.txt
RFC 5915: Elliptic Curve Private Key Structure, S. Turner, D. Brown2010-06-01T23:00:00-00:00This document specifies the syntax and semantics for conveying Elliptic Curve (EC) private key information. The syntax and semantics defined herein are based on similar syntax and semantics defined by the Standards for Efficient Cryptography Group (SECG). This document is not an Internet Standards Track specification; it is published for informational purposes.