Determine if a character is one of the permissible characters for
PrintableString:
A-Z, a-z, 0-9, space, apostrophe (39), left and right parentheses,
plus sign, comma, hyphen, period, slash, colon, equals sign,
and question mark.
Characters that are *not* allowed in PrintableString include
exclamation point, quotation mark, number sign, dollar sign,
percent sign, ampersand, asterisk, semicolon, less than sign,
greater than sign, at sign, left and right square brackets,
backslash, circumflex (94), underscore, back quote (96),
left and right curly brackets, vertical line, tilde,
and the control codes (0-31 and 127).
Determine if a character is one of the permissible characters for PrintableString: A-Z, a-z, 0-9, space, apostrophe (39), left and right parentheses, plus sign, comma, hyphen, period, slash, colon, equals sign, and question mark.
Characters that are *not* allowed in PrintableString include exclamation point, quotation mark, number sign, dollar sign, percent sign, ampersand, asterisk, semicolon, less than sign, greater than sign, at sign, left and right square brackets, backslash, circumflex (94), underscore, back quote (96), left and right curly brackets, vertical line, tilde, and the control codes (0-31 and 127).
This list is based on X.680 (the ASN.1 spec).