The pskc module implements a simple and efficient API for parsing PSKC files.
Importing data from a PSKC file can be done by instantiating a PSKC class:
from pskc import PSKC
pskc = PSKC('somefile.pskcxml')
The PSKC class is used as a wrapper to access information from a PSKC file. The whole file is parsed in one go. Instances of this class provide the following attributes:
A unique identifier for the container.
A list of pskc.key.Key instances that represent the keys within the PSKC file.
Instance of the pskc.encryption.Encryption class that handles PSKC file encryption.
Instance of the pskc.mac.MAC class that handles integrity checking.
The pskc.PSKC.keys attribute provides access to the keys contained in the PSKC file. Instances of the Key class provide access to a number of attributes that provide information on the transmitted keys:
pskc = PSKC('somefile.pskcxml')
first_key = pskc.keys[0]
Attribute values will be None if it the value is not present in the PSKC file.
A unique identifier for the key. If there are multiple interactions with the same key in multiple instances of PSKC files the id is supposed to remain the same.
A URI that identifies the PSKC algorithm profile. The algorithm profile associates specific semantics to the key. Some known profiles are:
The binary value of the transported secret key. If the key information is encrypted in the PSKC file it is transparently decrypted if possible.
The event counter for event-based OTP algorithms.
The time offset offset for time-based OTP algorithms. If time intervals are used it carries the number of time intervals passed from an algorithm-dependent start point.
The time interval in seconds for time-based OTP algorithms (usually 30 or 60).
For time-based OTP algorithms this contains the device clock drift in number of intervals.
The name of the party that issued the key. This may be different from the manufacturer of the device.
A reference to a pre-shared key profile agreed upon between the sending and receiving parties. The profile information itself is not transmitted within the container. See RFC6030.
A reference to an external key that is not contained within the PSKC file (e.g., a PKCS #11 key label). If this attribute is present, the secret attribute will generally be missing.
A human-readable name for the secret key.
The distinguished name of the user associated with the key. Also see device_userid.
The name of the manufacturer of the device to which the key is provisioned. RFC6030 prescribes that the value is of the form oath.prefix for OATH Manufacturer Prefixes or iana.organisation for IANA Private Enterprise Numbers however, it is generally just a string. The value may be different from the issuer of the key on the device.
The serial number of the device to which the key is provisioned. Together with manufacturer (and perhaps issue_no) this should uniquely identify the device.
A manufacturer specific description of the model of the device.
The issue number in case there are devices with the same serial number so that they can be distinguished by different issue numbers.
Reference to a device identifier (e.g. IMEI) that allows a provisioning server to ensure that the key is going to be loaded into a specific device.
datetime.datetime value that indicates that the device should only be used after this date.
datetime.datetime value that indicates that the device should only be used before this date. Systems should not rely upon the device to enforce key usage date restrictions, as some devices do not have an internal clock.
The distinguished name of the user associated with the device. Also see key_userid.
Implementation specific unique identifier of the cryptographic module on the device to which the keys have been (or will be) provisioned.
Additional algorithm specific characteristics. For example, in an HMAC-based algorithm it could designate the hash algorithm used (SHA1 or SHA256).
Encoding of the challenge accepted by the device for challenge-response authentication. One of:
The minimum size of the challenge accepted by the device.
The maximum size of the challenge accepted by the device.
Boolean that indicates whether the device will check an embedded Luhn check digit contained in the challenge.
Format of the response that is generated by the device. If must be one of the values as described under challenge_encoding.
The length of the response generated by the device.
Boolean that indicates whether the device will append a Luhn check digit to the response.
Instance of pskc.policy.Policy that provides key and PIN policy information. See Key usage policy.
Check if any MACs in the key data embedded in the PSKC file are valid. Will return a boolean or None if no MACs are defined for the key. See Integrity checking.