M3U8::Encryptable
Provides common functionality for constructing encryption key tags in HTTP Live Streaming (HLS).
According to RFC 8216, Section 4.3.2.4, the
EXT-X-KEY tag specifies the encryption parameters for Media Segments in an HLS playlist.
This tag includes several attributes:
#EXT-X-KEY:METHOD=AES-128,URI="http://test.key",IV=D512BBF,KEYFORMAT="identity",KEYFORMATVERSIONS="1/3"- METHOD (required): Specifies the encryption method (e.g. NONE, AES-128, SAMPLE-AES).
- URI (optional): The URI used to fetch the decryption key (optional if METHOD is NONE; required otherwise).
- IV (optional): The Initialization Vector, expressed as a hexadecimal sequence.
- KEYFORMAT (optional): A string that indicates the key format (defaults to "identity" if omitted).
- KEYFORMATVERSIONS (optional): Indicates the supported key format versions (defaults to 1 if omitted).
This module provides helper methods that convert parameter hashes into the correctly formatted
attribute string for inclusion in an EXT-X-KEY tag.
Constructors
Alternative constructor that accepts a NamedTuple with symbol keys.
Example:
options = {
method: "AES-128",
uri: "https://example.com/key",
iv: "0x1a2b3c",
key_format: "identity",
key_format_versions: "1",
}
class Something
include Encryptable
end
Something.new(options)
# => #<App::Something:0x78b71f3a9380
# @iv="0x1a2b3c",
# @key_format="identity",
# @key_format_versions="1",
# @method="AES-128",
# @uri="https://example.com/key">Initializes a new Encryptable instance with the given parameters.
Parameters:
method: The encryption method (required).uri: The URI for the key (optional).iv: The Initialization Vector IV (optional).key_format: The key format (optional).key_format_versions: The supported key format versions (optional).
class Something
include Encryptable
end
Something.new(method: "AES-128", uri: "https://example.com/key")
# => #<App::Something:0x7cae3cdbb2c0
# @iv=nil,
# @key_format=nil,
# @key_format_versions=nil,
# @method="AES-128",
# @uri="https://example.com/key">Class methods
Converts a hash of parameters (with keys in uppercase, as in a playlist) into a new hash with symbolized keys for internal use.
Expected keys are:
METHODURIIVKEYFORMATKEYFORMATVERSIONS.
Returns a NamedTuple.
Example:
options = {
"METHOD" => "AES-128",
"URI" => "http://test.key",
"IV" => "D512BBF",
"KEYFORMAT" => "identity",
"KEYFORMATVERSIONS" => "1/3",
}
Encryptable.convert_key(options)
# => {method: "AES-128",
# uri: "http://test.key",
# iv: "D512BBF",
# key_format: "identity",
# key_format_versions: "1/3"}Instance methods
Constructs a string representation of the encryption key attributes.
The output is a comma-separated list of attribute assignments,
suitable for inclusion in an EXT-X-KEY tag.
Example:
class Something
include Encryptable
end
Something.new(method: "AES-128", uri: "https://example.com/key").attributes_to_s
# => "METHOD=AES-128,URI=\"https://example.com/key\""The value is a hexadecimal-sequence that specifies a 128-bit unsigned integer Initialization Vector IV to be used with the key.
The value is a hexadecimal-sequence that specifies a 128-bit unsigned integer Initialization Vector IV to be used with the key.
The value is a string that specifies how the key is represented in the resource identified by the URI;
The value is a string that specifies how the key is represented in the resource identified by the URI;
The value is a string containing one or more positive
integers separated by the / character (for example, 1, 1/2, or 1/2/5).
The value is a string containing one or more positive
integers separated by the / character (for example, 1, 1/2, or 1/2/5).
The value is a string that specifies the encryption method.
The methods defined are: NONE, AES-128, and SAMPLE-AES.
An encryption method of NONE means that Media Segments are not encrypted.