ref: 0b2093c4da7fa81dba536efd67ff53e6d02cfdb6
dir: /sys/src/cmd/auth/rsa2any.h/
DSApriv*getdsakey(int argc, char **argv, int needprivate, Attr **pa); RSApriv*getkey(int argc, char **argv, int needprivate, Attr **pa); uchar* put4(uchar *p, uint n); uchar* putmp2(uchar *p, mpint *b); uchar* putn(uchar *p, void *v, uint n); uchar* putstr(uchar *p, char *s);