Decode from Base64

 

Decode from Base64: In computer programming, Base64 is a group of binary-to-text encoding schemes that represent binary data (more specifically, a sequence of 8-bit bytes) in sequences of 24 bits that can be represented by four 6-bit Base64 digits. Common to all binary-to-text encoding schemes, Base64 is designed to carry data stored in binary formats across channels that only reliably support text content. Base64 is particularly prevalent on the World Wide Web[1] where one of its uses is the ability to embed image files or other binary assets inside textual assets such as HTML and CSS files. Base64 is also widely used for sending e-mail attachments. This is required because SMTP – in its original form – was designed to transport 7-bit ASCII characters only. This encoding causes an overhead of 33–37% (33% by the encoding itself; up to 4% more by the inserted line breaks).

Decode from Base64 design

The particular set of 64 characters chosen to represent the 64-digit values for the base varies between implementations. The general strategy is to choose 64 characters that are common to most encodings and that are also printable. This combination leaves the data unlikely to be modified in transit through information systems, such as email, that were traditionally not 8-bit clean.[3] For example, MIME’s Base64 implementation uses A–Z, a–z, and 0–9 for the first 62 values. Other variations share this property but differ in the symbols chosen for the last two values; an example is UTF-7.

Evolution of Encoding Methods:

In the early days of computer communication, encoding methods were devised to facilitate data exchange between systems running the same operating system. One of the earliest encoding schemes was uuencode for UNIX and BinHex for the TRS-80, which was later adapted for the Macintosh. These encoding methods, at that time, had the advantage of making certain assumptions about the safety of characters used in communication. For example, uuencode relied on uppercase letters, digits, and a wide range of punctuation characters, while entirely excluding lowercase letters. Base64 worked well within the constraints of the systems it was designed for, where compatibility was high, and communication primarily occurred between similar platforms.

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