aws_encryption_sdk.internal.formatting.encryption_context¶

Components for handling serialization and deserialization of encryption context data in AWS Encryption SDK messages.

Functions

`assemble_content_aad`(message_id, …)	Assembles the Body AAD string for a message body structure.
`deserialize_encryption_context`(…)	Deserializes the contents of a byte string into a dictionary.
`read_short`(source, offset)	Reads a number from a byte array.
`read_string`(source, offset, length)	Reads a string from a byte string.
`serialize_encryption_context`(encryption_context)	Serializes the contents of a dictionary into a byte string.

aws_encryption_sdk.internal.formatting.encryption_context.assemble_content_aad(message_id, aad_content_string, seq_num, length)¶

Assembles the Body AAD string for a message body structure.

Parameters:	message_id (str) – Message ID aad_content_string (aws_encryption_sdk.identifiers.ContentAADString) – ContentAADString object for frame type seq_num (int) – Sequence number of frame length (int) – Content Length
Returns:	Properly formatted AAD bytes for message body structure.
Return type:	bytes
Raises:	SerializationError – if aad_content_string is not known

aws_encryption_sdk.internal.formatting.encryption_context.deserialize_encryption_context(serialized_encryption_context)¶

Deserializes the contents of a byte string into a dictionary.

Parameters:	serialized_encryption_context (bytes) – Source byte string containing serialized dictionary
Returns:	Deserialized encryption context
Return type:	dict
Raises:	SerializationError – if serialized encryption context is too large SerializationError – if duplicate key found in serialized encryption context SerializationError – if malformed data found in serialized encryption context

aws_encryption_sdk.internal.formatting.encryption_context.read_short(source, offset)¶

Reads a number from a byte array.

Parameters:	source (bytes) – Source byte string offset (int) – Point in byte string to start reading
Returns:	Read number and offset at point after read data
Return type:	tuple of ints
Raises:	SerializationError if unable to unpack

aws_encryption_sdk.internal.formatting.encryption_context.read_string(source, offset, length)¶

Reads a string from a byte string.

Parameters:	source (bytes) – Source byte string offset (int) – Point in byte string to start reading length (int) – Length of string to read
Returns:	Read string and offset at point after read data
Return type:	tuple of str and int
Raises:	SerializationError – if unable to unpack

aws_encryption_sdk.internal.formatting.encryption_context.serialize_encryption_context(encryption_context)¶

Serializes the contents of a dictionary into a byte string.

Parameters:	encryption_context (dict) – Dictionary of encrytion context keys/values.
Returns:	Serialized encryption context
Return type:	bytes