#Mathematica 170
Mathematica 170
r=RandomSample;f[i_]:=(FromCharacterCode/@Range@@i);
{t,A,a,n}=f/@{{33,126},{65,90},{97,122},{48,57}};
s=Complement[t,A,a,n];
""<>r[Join[RandomChoice/@{A,a,n,s},r[t,11]],15]
Examples
"<]}Pg3/e?3+Z~Oz"
"X/8jWe@f(_x5P:="
"2wz2VQhtJC?*R7^"