[cm/prv/] with GOST R 34.10-2012.
GOST R 34.10-2012 is signing/key-aggreement algorithm.
=> RFC 7091, GOST R 34.10-2012
Big-endian private key representation must be used.
Only twisted Edwards curves are used.

    prv-gost3410-256A {
        {field . {map} len=~}
        {field a {str} =gost3410-256A}
        {field v {bin} len=32}
    }
    
    prv-gost3410-512C {
        {field . {map} len=~}
        {field a {str} =gost3410-512C}
        {field v {bin} len=64}
    }