Tool to decrypt/encrypt with base 64. Base64 is a coding system using 64 characters, selected to be compatible with a majority of coding tables. It is used with emails for example.

Base64 Coding - dCode

Tag(s) : Character Encoding, Internet

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Tool to decrypt/encrypt with base 64. Base64 is a coding system using 64 characters, selected to be compatible with a majority of coding tables. It is used with emails for example.

**Base 64** encoding requires a binary input. For a text, the values depend on its coding (often ASCII or Unicode).

Example: To code DCODE that is written 01100100 01000011 01101111 01100100 01100101 in binary (ASCII code)

**Base 64** Coding starts by splitting the binary code in groups of 6 bits, filling it with 0 if needed.

Example: Split as 011001 000100 001101 101111 011001 000110 0101 (+00)

Each group of 6 bits has a base 10 value, it corresponds to a character in the **Base 64** alphabet (start at 0): ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/

0 | A | 1 | B | 2 | C | 3 | D | 4 | E | 5 | F | 6 | G | 7 | H |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|

8 | I | 9 | J | 10 | K | 11 | L | 12 | M | 13 | N | 14 | O | 15 | P |

16 | Q | 17 | R | 18 | S | 19 | T | 20 | U | 21 | V | 22 | W | 23 | X |

24 | Y | 25 | Z | 26 | a | 27 | b | 28 | c | 29 | d | 30 | e | 31 | f |

32 | g | 33 | h | 34 | i | 35 | j | 36 | k | 37 | l | 38 | m | 39 | n |

40 | o | 41 | p | 42 | q | 43 | r | 44 | s | 45 | t | 46 | u | 47 | v |

48 | w | 49 | x | 50 | y | 51 | z | 52 | 0 | 53 | 1 | 54 | 2 | 55 | 3 |

56 | 4 | 57 | 5 | 58 | 6 | 59 | 7 | 60 | 8 | 61 | 9 | 62 | + | 63 | / |

Example: The conversion from 011001 to base 10 is 25 and in the alphabet 25 is Z, 000100 is 4, etc. to obtain the characters numbered 25 4 13 47 25 6 20 or the coded message: ZENvZGU

**Base 64** only works with groups of 4 characters, if needed, fill with =.

Example: Finally ZENvZGU (that had 7 chars) becomes ZENvZGU= (8 chars, a multiple of 4) which is the final **base64** encoded message.

Decryption consists in finding back values of the letters in the **Base64** alphabet: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/ (equal sign = is ignored)

Example: A coded message is YjY0, corresponding values of Y,j,Y,0 in the alphabet are: 24,35,24,52

Values are converted to 6-bit binary.

Example: 24 is converted 011000, 35 = 100011, etc. the decoded binary message is 011000100011011000110100

**Base64** decoding is then complete. Binary message is then read using the desired coding system (ASCII, Unicode, etc.)

Example: In ASCII, 01100010,00110110,00110100 corresponds to the plain text b,6,4

The message is theoretically composed of a number of characters multiple of 4. To this end, the presence of characters = (equal) at the end of the message is a big clue.

The message has a maximum of 65 distinct characters (and possibly space or line break). By default it is: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=

**Base64** is typically used in emails for non-ASCII messages and attachments (via the MIME standard: Multipurpose Internet Mail Extensions)

The Usenet network used **Base64** to transfer files, any indication referring to it is a clue.

In **Base64**, 4 ASCII characters are used to code 3 bytes. Volume is increased by 33%.

Example: **Base64** (6 characters) is coded QmFzZTY0 (8 characters or +33%)

**base64** (no uppercase) is coded YmFzZTY0

The **base64** uses a sixty-four character alphabet to code any binary string (in base 2), so it is a mathematical convertion in **base 64**.

Characters 62 + and 63 / can cause problems with URL, they can be remplaced by respectively - and _. The equal = sign is deleted.

RFC 2045 norm officialising **Base64** is from 1996

dCode retains ownership of the source code of the script Base64 Coding online. Except explicit open source licence (indicated Creative Commons / free), any algorithm, applet, snippet, software (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any function (convert, solve, decrypt, encrypt, decipher, cipher, decode, code, translate) written in any informatic langauge (PHP, Java, C#, Python, Javascript, Matlab, etc.) which dCode owns rights will not be released for free. To download the online Base64 Coding script for offline use on PC, iPhone or Android, ask for price quote on contact page !

base,base64,64,mime,usenet,email,sixty,four,qmfzzty0,ymfzzty0,base64url,equal

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