The decoding process does the opposite of the above encoding process. Finally a single pad (=) character is appended to the output. Each of the three 6-bit groups is converted to the corresponding Base64 alphabet. Input has 16 bits remaining at the end: Two zero bits are added to form three 6-bit groups.Base64 also uses the symbol as a padding character on the. After that two pad (=) characters are appended to the output. Base64 has 64 possible characters that the output can be encoded as a-z, A-Z, 0-9, +, and /. Each 6-bit group is converted to the resulting Base64 encoded character using the Base64 index table. Input has 8 bits remaining at the end: Four zero bits are added to form two 6-bit groups.Then, one or two pad (=) characters are output depending on the following cases. When the input has fewer than 24 bits at the end, zero bits are added (on the right) to form an integral number of 6-bit groups. Finally, each 6-bit group is converted to a single character in the Base64 alphabet by consulting the above Base64 alphabet table. These 24-bit groups are then treated as 4 concatenated 6-bit groups. It processes the input from left to right and organizes the input into 24-bit groups by concatenating three 8-bit bytes. The Base64 encoding process receives input in the form of of 8-bit bytes. If SourceExpression is of CHARACTER type, it is first converted to the UTF-8 code page before encoding as base64. Each alphabet is represented by a 6-bit sequence from 0 to 63. The following table displays the list of Base64 alphabets. The extra 65th character ( =) is used to pad the Base64 encoded output. These characters form the Base64 alphabet. The first 64 characters are represented using a 6-bit sequence ( 2 6 = 64). These characters are A-Z, a-z, 0-9, +, /, and =. The decoding process converts the encoded string back to binary data.īase64 encoding uses a subset of 65 characters from the US-ASCII charset. The encoding process converts binary data to a printable ASCII string format. To transfer non-ASCII or binary data over such communication channels, the binary data is encoded to the ASCII charset using Base64 encoding scheme. Many communication protocols like SMTP, NNTP were traditionally designed to work with plain text data represented by the 7-bit US-ASCII character set. Listed here are a few examples on how to embed Base64 resources within different web documents.ĭata:image/jpeg base64,/9j/4AAQSkZJRgABAQEAWgBaAAD/4gxYSUNDX1BST0ZJTEUAAQEAAAxITGlubwIQAAB.īackground-image: url('data:image/jpeg base64,/9j/4AAQSkZJRgABAQEAWgBaAAD/4gxYSUNDX1BST0ZJTEUAAQEAAAxITGlubwIQAAB.Base64 encoding is a binary-to-text encoding/decoding scheme.īase64 encoding is used when any binary data needs to be transmitted over a media that is designed to handle only textual data. How can I embed Base64 encoded resource directly into HTML, XML and CSS files? If the number of bytes are not in numbers of three, then padding is used = for 1 byte and = for 2 bytes.Ĭonsult wikipedia for more information. Those 6 bits form a number corresponding to the index in the character set supported by Base64 (A-Z, a-z, 0-9, + and /). The resulting buffer of 3 bytes is then broken in 4 packs of 6 bits each. How does Base64 encoding work?īytes forming the data are broken into buffers of 24 bits (3 bytes at a time). Concrete examples would be sending images in an XML file or in an email attachment. This is useful when binary data needs to be sent over media that are usually designed to handle textual data. Message Digester (MD5, SHA-256, SHA-512)īase64 is an encoding scheme used to represent binary data in an ASCII format.Credit Card Number Generator & Validator.
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