# Elixir v1.10.3 Base View Source

This module provides data encoding and decoding functions according to RFC 4648.

This document defines the commonly used base 16, base 32, and base 64 encoding schemes.

## Base 16 alphabet

Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding
--- | --- | --- | --- | --- | --- | --- | ---
0 | 0 | 4 | 4 | 8 | 8 | 12 | C
1 | 1 | 5 | 5 | 9 | 9 | 13 | D
2 | 2 | 6 | 6 | 10 | A | 14 | E
3 | 3 | 7 | 7 | 11 | B | 15 | F

## Base 32 alphabet

Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding
--- | --- | --- | --- | --- | --- | --- | ---
0 | A | 9 | J | 18 | S | 27 | 3
1 | B | 10 | K | 19 | T | 28 | 4
2 | C | 11 | L | 20 | U | 29 | 5
3 | D | 12 | M | 21 | V | 30 | 6
4 | E | 13 | N | 22 | W | 31 | 7
5 | F | 14 | O | 23 | X |  |
6 | G | 15 | P | 24 | Y | (pad) | =
7 | H | 16 | Q | 25 | Z |  |
8 | I | 17 | R | 26 | 2 |  |

## Base 32 (extended hex) alphabet

Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding
--- | --- | --- | --- | --- | --- | --- | ---
0 | 0 | 9 | 9 | 18 | I | 27 | R
1 | 1 | 10 | A | 19 | J | 28 | S
2 | 2 | 11 | B | 20 | K | 29 | T
3 | 3 | 12 | C | 21 | L | 30 | U
4 | 4 | 13 | D | 22 | M | 31 | V
5 | 5 | 14 | E | 23 | N |  |
6 | 6 | 15 | F | 24 | O | (pad) | =
7 | 7 | 16 | G | 25 | P |  |
8 | 8 | 17 | H | 26 | Q |  |

## Base 64 alphabet

Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding
--- | --- | --- | --- | --- | --- | --- | ---
0 | A | 17 | R | 34 | i | 51 | z
1 | B | 18 | S | 35 | j | 52 | 0
2 | C | 19 | T | 36 | k | 53 | 1
3 | D | 20 | U | 37 | l | 54 | 2
4 | E | 21 | V | 38 | m | 55 | 3
5 | F | 22 | W | 39 | n | 56 | 4
6 | G | 23 | X | 40 | o | 57 | 5
7 | H | 24 | Y | 41 | p | 58 | 6
8 | I | 25 | Z | 42 | q | 59 | 7
9 | J | 26 | a | 43 | r | 60 | 8
10 | K | 27 | b | 44 | s | 61 | 9
11 | L | 28 | c | 45 | t | 62 | +
12 | M | 29 | d | 46 | u | 63 | /
13 | N | 30 | e | 47 | v |  |
14 | O | 31 | f | 48 | w | (pad) | =
15 | P | 32 | g | 49 | x |  |
16 | Q | 33 | h | 50 | y |  |

## Base 64 (URL and filename safe) alphabet

Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding
--- | --- | --- | --- | --- | --- | --- | ---
0 | A | 17 | R | 34 | i | 51 | z
1 | B | 18 | S | 35 | j | 52 | 0
2 | C | 19 | T | 36 | k | 53 | 1
3 | D | 20 | U | 37 | l | 54 | 2
4 | E | 21 | V | 38 | m | 55 | 3
5 | F | 22 | W | 39 | n | 56 | 4
6 | G | 23 | X | 40 | o | 57 | 5
7 | H | 24 | Y | 41 | p | 58 | 6
8 | I | 25 | Z | 42 | q | 59 | 7
9 | J | 26 | a | 43 | r | 60 | 8
10 | K | 27 | b | 44 | s | 61 | 9
11 | L | 28 | c | 45 | t | 62 | -
12 | M | 29 | d | 46 | u | 63 | _
13 | N | 30 | e | 47 | v |  |
14 | O | 31 | f | 48 | w | (pad) | =
15 | P | 32 | g | 49 | x |  |
16 | Q | 33 | h | 50 | y |  |

# Link to this section Summary

## Functions

decode16(string, opts \\ [])

Decodes a base 16 encoded string into a binary string.

decode16!(string, opts \\ [])

Decodes a base 16 encoded string into a binary string.

decode32(string, opts \\ [])

Decodes a base 32 encoded string into a binary string.

decode32!(string, opts \\ [])

Decodes a base 32 encoded string into a binary string.

decode64(string, opts \\ [])

Decodes a base 64 encoded string into a binary string.

decode64!(string, opts \\ [])

Decodes a base 64 encoded string into a binary string.

encode16(data, opts \\ [])

Encodes a binary string into a base 16 encoded string.

encode32(data, opts \\ [])

Encodes a binary string into a base 32 encoded string.

encode64(data, opts \\ [])

Encodes a binary string into a base 64 encoded string.

hex_decode32(string, opts \\ [])

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string.

hex_decode32!(string, opts \\ [])

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string.

hex_encode32(data, opts \\ [])

Encodes a binary string into a base 32 encoded string with an extended hexadecimal alphabet.

url_decode64(string, opts \\ [])

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string.

url_decode64!(string, opts \\ [])

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string.

url_encode64(data, opts \\ [])

Encodes a binary string into a base 64 encoded string with URL and filename safe alphabet.

# Link to this section Functions

Link to this function

# decode16(string, opts \\ [])

View Source

## Specs

    decode16(binary(), keyword()) :: {:ok, binary()} | :error

Decodes a base 16 encoded string into a binary string.

## Options

The accepted options are:

- `:case` - specifies the character case to accept when decoding

The values for `:case` can be:

- `:upper` - only allows upper case characters (default)
- `:lower` - only allows lower case characters
- `:mixed` - allows mixed case characters

## Examples

    iex> Base.decode16("666F6F626172")
    {:ok, "foobar"}

    iex> Base.decode16("666f6f626172", case: :lower)
    {:ok, "foobar"}

    iex> Base.decode16("666f6F626172", case: :mixed)
    {:ok, "foobar"}

Link to this function

# decode16!(string, opts \\ [])

View Source

## Specs

    decode16!(binary(), keyword()) :: binary()

Decodes a base 16 encoded string into a binary string.

## Options

The accepted options are:

- `:case` - specifies the character case to accept when decoding

The values for `:case` can be:

- `:upper` - only allows upper case characters (default)
- `:lower` - only allows lower case characters
- `:mixed` - allows mixed case characters

An `ArgumentError` exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

## Examples

    iex> Base.decode16!("666F6F626172")
    "foobar"

    iex> Base.decode16!("666f6f626172", case: :lower)
    "foobar"

    iex> Base.decode16!("666f6F626172", case: :mixed)
    "foobar"

Link to this function

# decode32(string, opts \\ [])

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## Specs

    decode32(binary(), keyword()) :: {:ok, binary()} | :error

Decodes a base 32 encoded string into a binary string.

## Options

The accepted options are:

- `:case` - specifies the character case to accept when decoding
- `:padding` - specifies whether to require padding

The values for `:case` can be:

- `:upper` - only allows upper case characters (default)
- `:lower` - only allows lower case characters
- `:mixed` - allows mixed case characters

The values for `:padding` can be:

- `true` - requires the input string to be padded to the nearest multiple of 8 (default)
- `false` - ignores padding from the input string

## Examples

    iex> Base.decode32("MZXW6YTBOI======")
    {:ok, "foobar"}

    iex> Base.decode32("mzxw6ytboi======", case: :lower)
    {:ok, "foobar"}

    iex> Base.decode32("mzXW6ytBOi======", case: :mixed)
    {:ok, "foobar"}

    iex> Base.decode32("MZXW6YTBOI", padding: false)
    {:ok, "foobar"}

Link to this function

# decode32!(string, opts \\ [])

View Source

## Specs

    decode32!(binary(), keyword()) :: binary()

Decodes a base 32 encoded string into a binary string.

An `ArgumentError` exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

## Options

The accepted options are:

- `:case` - specifies the character case to accept when decoding
- `:padding` - specifies whether to require padding

The values for `:case` can be:

- `:upper` - only allows upper case characters (default)
- `:lower` - only allows lower case characters
- `:mixed` - allows mixed case characters

The values for `:padding` can be:

- `true` - requires the input string to be padded to the nearest multiple of 8 (default)
- `false` - ignores padding from the input string

## Examples

    iex> Base.decode32!("MZXW6YTBOI======")
    "foobar"

    iex> Base.decode32!("mzxw6ytboi======", case: :lower)
    "foobar"

    iex> Base.decode32!("mzXW6ytBOi======", case: :mixed)
    "foobar"

    iex> Base.decode32!("MZXW6YTBOI", padding: false)
    "foobar"

Link to this function

# decode64(string, opts \\ [])

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## Specs

    decode64(binary(), keyword()) :: {:ok, binary()} | :error

Decodes a base 64 encoded string into a binary string.

Accepts `ignore: :whitespace` option which will ignore all the whitespace characters in the input string.

Accepts `padding: false` option which will ignore padding from the input string.

## Examples

    iex> Base.decode64("Zm9vYmFy")
    {:ok, "foobar"}

    iex> Base.decode64("Zm9vYmFy\n", ignore: :whitespace)
    {:ok, "foobar"}

    iex> Base.decode64("Zm9vYg==")
    {:ok, "foob"}

    iex> Base.decode64("Zm9vYg", padding: false)
    {:ok, "foob"}

Link to this function

# decode64!(string, opts \\ [])

View Source

## Specs

    decode64!(binary(), keyword()) :: binary()

Decodes a base 64 encoded string into a binary string.

Accepts `ignore: :whitespace` option which will ignore all the whitespace characters in the input string.

Accepts `padding: false` option which will ignore padding from the input string.

An `ArgumentError` exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

## Examples

    iex> Base.decode64!("Zm9vYmFy")
    "foobar"

    iex> Base.decode64!("Zm9vYmFy\n", ignore: :whitespace)
    "foobar"

    iex> Base.decode64!("Zm9vYg==")
    "foob"

    iex> Base.decode64!("Zm9vYg", padding: false)
    "foob"

Link to this function

# encode16(data, opts \\ [])

View Source

## Specs

    encode16(binary(), keyword()) :: binary()

Encodes a binary string into a base 16 encoded string.

## Options

The accepted options are:

- `:case` - specifies the character case to use when encoding

The values for `:case` can be:

- `:upper` - uses upper case characters (default)
- `:lower` - uses lower case characters

## Examples

    iex> Base.encode16("foobar")
    "666F6F626172"

    iex> Base.encode16("foobar", case: :lower)
    "666f6f626172"

Link to this function

# encode32(data, opts \\ [])

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## Specs

    encode32(binary(), keyword()) :: binary()

Encodes a binary string into a base 32 encoded string.

## Options

The accepted options are:

- `:case` - specifies the character case to use when encoding
- `:padding` - specifies whether to apply padding

The values for `:case` can be:

- `:upper` - uses upper case characters (default)
- `:lower` - uses lower case characters

The values for `:padding` can be:

- `true` - pad the output string to the nearest multiple of 8 (default)
- `false` - omit padding from the output string

## Examples

    iex> Base.encode32("foobar")
    "MZXW6YTBOI======"

    iex> Base.encode32("foobar", case: :lower)
    "mzxw6ytboi======"

    iex> Base.encode32("foobar", padding: false)
    "MZXW6YTBOI"

Link to this function

# encode64(data, opts \\ [])

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## Specs

    encode64(binary(), keyword()) :: binary()

Encodes a binary string into a base 64 encoded string.

Accepts `padding: false` option which will omit padding from the output string.

## Examples

    iex> Base.encode64("foobar")
    "Zm9vYmFy"

    iex> Base.encode64("foob")
    "Zm9vYg=="

    iex> Base.encode64("foob", padding: false)
    "Zm9vYg"

Link to this function

# hex_decode32(string, opts \\ [])

View Source

## Specs

    hex_decode32(binary(), keyword()) :: {:ok, binary()} | :error

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string.

## Options

The accepted options are:

- `:case` - specifies the character case to accept when decoding
- `:padding` - specifies whether to require padding

The values for `:case` can be:

- `:upper` - only allows upper case characters (default)
- `:lower` - only allows lower case characters
- `:mixed` - allows mixed case characters

The values for `:padding` can be:

- `true` - requires the input string to be padded to the nearest multiple of 8 (default)
- `false` - ignores padding from the input string

## Examples

    iex> Base.hex_decode32("CPNMUOJ1E8======")
    {:ok, "foobar"}

    iex> Base.hex_decode32("cpnmuoj1e8======", case: :lower)
    {:ok, "foobar"}

    iex> Base.hex_decode32("cpnMuOJ1E8======", case: :mixed)
    {:ok, "foobar"}

    iex> Base.hex_decode32("CPNMUOJ1E8", padding: false)
    {:ok, "foobar"}

Link to this function

# hex_decode32!(string, opts \\ [])

View Source

## Specs

    hex_decode32!(binary(), keyword()) :: binary()

Decodes a base 32 encoded string with extended hexadecimal alphabet into a binary string.

An `ArgumentError` exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

## Options

The accepted options are:

- `:case` - specifies the character case to accept when decoding
- `:padding` - specifies whether to require padding

The values for `:case` can be:

- `:upper` - only allows upper case characters (default)
- `:lower` - only allows lower case characters
- `:mixed` - allows mixed case characters

The values for `:padding` can be:

- `true` - requires the input string to be padded to the nearest multiple of 8 (default)
- `false` - ignores padding from the input string

## Examples

    iex> Base.hex_decode32!("CPNMUOJ1E8======")
    "foobar"

    iex> Base.hex_decode32!("cpnmuoj1e8======", case: :lower)
    "foobar"

    iex> Base.hex_decode32!("cpnMuOJ1E8======", case: :mixed)
    "foobar"

    iex> Base.hex_decode32!("CPNMUOJ1E8", padding: false)
    "foobar"

Link to this function

# hex_encode32(data, opts \\ [])

View Source

## Specs

    hex_encode32(binary(), keyword()) :: binary()

Encodes a binary string into a base 32 encoded string with an extended hexadecimal alphabet.

## Options

The accepted options are:

- `:case` - specifies the character case to use when encoding
- `:padding` - specifies whether to apply padding

The values for `:case` can be:

- `:upper` - uses upper case characters (default)
- `:lower` - uses lower case characters

The values for `:padding` can be:

- `true` - pad the output string to the nearest multiple of 8 (default)
- `false` - omit padding from the output string

## Examples

    iex> Base.hex_encode32("foobar")
    "CPNMUOJ1E8======"

    iex> Base.hex_encode32("foobar", case: :lower)
    "cpnmuoj1e8======"

    iex> Base.hex_encode32("foobar", padding: false)
    "CPNMUOJ1E8"

Link to this function

# url_decode64(string, opts \\ [])

View Source

## Specs

    url_decode64(binary(), keyword()) :: {:ok, binary()} | :error

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string.

Accepts `ignore: :whitespace` option which will ignore all the whitespace characters in the input string.

Accepts `padding: false` option which will ignore padding from the input string.

## Examples

    iex> Base.url_decode64("_3_-_A==")
    {:ok, <<255, 127, 254, 252>>}

    iex> Base.url_decode64("_3_-_A==\n", ignore: :whitespace)
    {:ok, <<255, 127, 254, 252>>}

    iex> Base.url_decode64("_3_-_A", padding: false)
    {:ok, <<255, 127, 254, 252>>}

Link to this function

# url_decode64!(string, opts \\ [])

View Source

## Specs

    url_decode64!(binary(), keyword()) :: binary()

Decodes a base 64 encoded string with URL and filename safe alphabet into a binary string.

Accepts `ignore: :whitespace` option which will ignore all the whitespace characters in the input string.

Accepts `padding: false` option which will ignore padding from the input string.

An `ArgumentError` exception is raised if the padding is incorrect or a non-alphabet character is present in the string.

## Examples

    iex> Base.url_decode64!("_3_-_A==")
    <<255, 127, 254, 252>>

    iex> Base.url_decode64!("_3_-_A==\n", ignore: :whitespace)
    <<255, 127, 254, 252>>

    iex> Base.url_decode64!("_3_-_A", padding: false)
    <<255, 127, 254, 252>>

Link to this function

# url_encode64(data, opts \\ [])

View Source

## Specs

    url_encode64(binary(), keyword()) :: binary()

Encodes a binary string into a base 64 encoded string with URL and filename safe alphabet.

Accepts `padding: false` option which will omit padding from the output string.

## Examples

    iex> Base.url_encode64(<<255, 127, 254, 252>>)
    "_3_-_A=="

    iex> Base.url_encode64(<<255, 127, 254, 252>>, padding: false)
    "_3_-_A"