Format-preserving cryptographic systems
First Claim
1. A method for performing decryption at computing equipment in a data processing system that has a key server, the method comprising:
- at the computing equipment, obtaining ciphertext;
with the computing equipment, providing, to the key server, a key request that includes an identifier;
at the key server, selecting policy rules to apply to the key request based at least partly on whether the identifier includes a label indicating that the ciphertext is associated with a type of data used for payments;
at the key server, applying the selected policy rules to determine whether to fulfill the key request;
when the selected policy rules are satisfied, generating a key at the key server in fulfillment of the key request using a one-way function that accepts a root secret and the identifier as inputs;
at the key server, transmitting the key;
at the computing equipment, receiving the key; and
with a format-preserving decryption algorithm implemented on the computing equipment, decrypting the ciphertext using the key.
11 Assignments
0 Petitions
Accused Products
Abstract
Key requests in a data processing system may include identifiers such as user names, policy names, and application names. The identifiers may also include validity period information indicating when corresponding keys are valid. When fulfilling a key request, a key server may use identifier information from the key request in determining which key access policies to apply and may use the identifier in determining whether an applicable policy has been satisfied. When a key request is authorized, the key server may generate a key by applying a one-way function to a root secret and the identifier. Validity period information for use by a decryption engine may be embedded in data items that include redundant information. Application testing can be facilitated by populating a test database with data that has been encrypted using a format-preserving encryption algorithm. Parts of a data string may be selectively encrypted based on their sensitivity.
-
Citations
17 Claims
-
1. A method for performing decryption at computing equipment in a data processing system that has a key server, the method comprising:
-
at the computing equipment, obtaining ciphertext; with the computing equipment, providing, to the key server, a key request that includes an identifier; at the key server, selecting policy rules to apply to the key request based at least partly on whether the identifier includes a label indicating that the ciphertext is associated with a type of data used for payments; at the key server, applying the selected policy rules to determine whether to fulfill the key request; when the selected policy rules are satisfied, generating a key at the key server in fulfillment of the key request using a one-way function that accepts a root secret and the identifier as inputs; at the key server, transmitting the key; at the computing equipment, receiving the key; and with a format-preserving decryption algorithm implemented on the computing equipment, decrypting the ciphertext using the key. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method for performing decryption at computing equipment in a data processing system that has a key server, the method comprising:
-
at the computing equipment, obtaining ciphertext; with the computing equipment, providing, to the key server, a key request that includes an identifier; at the key server, selecting a first policy rule to apply to the key request when the identifier includes a label that identifies that the ciphertext includes a credit card number; at the key server, selecting a second policy rule, which is different from the first policy rule, to apply to the key request when the identifier does not include the label that identifies that the ciphertext includes the credit card number; at the key server, applying the first selected policy rule to determine whether to fulfill the key request when the identifier includes the label that identifies that the ciphertext includes the credit card number; at the key server, applying the second selected policy rule to determine whether to fulfill the key request when the identifier includes the label that identifies that the ciphertext includes the credit card number; when one of the first and second selected policy rules is satisfied, obtaining a key at the key server in fulfillment of the key request; at the key server, transmitting the key; at the computing equipment, receiving the key; and with a format-preserving decryption algorithm implemented on the computing equipment, decrypting the ciphertext using the key. - View Dependent Claims (16, 17)
-
Specification