EPIC Vigenere

// argv[1] is string key
// p is user entered string
for (int i = 0, j=0, l = strlen(p), kl=strlen(argv[1]); i < l; i++) printf("%c", isalpha(p[i])?((((((p[i]-1)&((char)~(7<<5)))+((argv[1][(j++)%kl]-1)&(char)~(7<<5)))%26)+1)|((p[i]>>5)<<5)):p[i]);