Base64 encoding

Base64 encoding ensures that the output only contains characters from a specific, limited set of 64 characters, which are: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/

It is safe for most text-based systems because none of the potentially problematic characters (\, \0, \n, \r, \x1a, ', ") appear in the output. Note that \x1a is the hexadecimal representation of the ASCII control character SUB (substitute). It is a non-printable character with the decimal value 26 in the ASCII table. If included in a text string, \x1a is typically invisible and may disrupt processing, especially in legacy systems that interpret it as EOF.

Example:

Base64 encoding increases the size of the input data by approximately 33%. Specifically: For every 3 bytes of input, base64 adds 4 characters. For example if input JSON is {"customer_id":123,"email":"user@example.com","nonce":"d1a2b3c4d5e6f7g8h9i0j1k2l3m4n5o6"}, which is 94 characters, the output will be eyJjdXN0b21lcl9pZCI6IDEyMywgImVtYWlsIjogInVzZXJAZXhhbXBsZS5jb20iLCAibm9uY2UiOiAiZjVkMGMzZGY3ZTM3ODQ2NWQ0NjhkMTdjZTRhNGNlMzIifQ==, which is 128 characters. Note the "==" characters at the end. These are used for padding which ensures the length of the encoded string is a multiple of 4. If your database column to hold the token is VARCHAR(255), assuming a max customer_id of "999 999 999", max email size should not exceed 111 characters.

Email max lengths [RFC 5321, Simple Mail Transfer Protocol]:

• Local part (before the @): Up to 64 characters (octet = byte).
• Domain part (after the @): Up to 255 characters.

Total length: The maximum length of a valid email address is 320 characters, but this is extremely rare in practice.

Music: Barış Manço - Dönence