Abstract: A time stamping protocol has two stages referred to as the ticketing stage and the certification stage. During the ticketing stage, the document or other identifying data is sent to the TSA. The TSA generates a “ticket” based on the document or other identifying data and a time indication derived from a trusted clock. The ticket, which serves as an unsigned time stamp receipt, is transmitted back to the document originator. During the certification stage, the holder of the ticket requests a certified time stamp receipt by presenting the ticket to the TSA. The TSA verifies the ticket and generates a signed time stamp receipt, called the ticket stub, which is then transmitted back to the document originator.

Abstract: A method for protecting data for access by a plurality of users. A server encrypts data using a master key and a symmetric encryption algorithm. For each authorized user, a key encryption key (KEK) is derived from a passphrase, and the master key is encrypted using the KEK. The server posts the encrypted data and an ancillary file that includes, for each user, a user identifier and the master key encrypted according to the user's KEK. To access the data, a user enters the passphrase into a client, which re-derives the user's KEK, and finds, in the ancillary file, the master key encrypted using the user's KEK. The client decrypts the master key and then decrypts the data. A KEK may be derived from a natural language passphrase by hashing the passphrase, concatenating the result and a predetermined text, hashing the concatenation, and truncating.

Abstract: Methods, systems and computer program products are provide for controlling access to software is provided by the software to be controlled being divided into a first encrypted portion and a second unencrypted portion. The second unencrypted portion has access to, and may even incorporate, a first secret value and a software identification associated with a copy of the software. The first encrypted portion is encrypted with a first key value which is based on the first secret value and a second secret value. The second secret value is obtained and the first key value generated from the obtained second secret value and the first secret value. The first encrypted portion of the software may then be decrypted with the first key value. The software may be installed on a data processing system utilizing the decrypted first encrypted portion of the software.

Abstract: Methods, systems and computer program products are provided for controlling access to digital data in a file by obtaining a passphrase from a user and generating a personal key based on the obtained passphrase. A file encryption key is generated and the digital data in the file encrypted with the file encryption key to provide an encrypted file. The file encryption key is encrypted with the personal key to provide an encrypted file encryption key. A file header containing the encrypted file encryption key and associated with the encrypted file. The encrypted file and the file header associated with the encrypted file may be stored at a file server.

Abstract: A method for time stamping a digital document is disclosed. The document originator creates a time stamp receipt by combining the document or other identifying data and a digital time indication. The time stamp receipt is submitted to a time stamping authority having a trusted clock. The time stamping authority optionally validates the time stamp receipt and then computes the age of the time stamp receipt. The time stamping authority creates an aged time stamp receipt by combining the identifying data and time indication contained in the submitted time stamp receipt with the computed age of the time stamp receipt. The time stamping authority cryptographically binds the time information and identifying data in the aged time stamp receipt, e.g., by signing the combination of the identifying data, time indication, and computed age with a private signature generation key.

Abstract: A time-stamping protocol for time-stamping digital documents uses a time-based signature key. A document or other identifying data is sent to a time stamping authority TSA. The TSA has a time-based signature key that the TSA uses to sign time stamp receipts. The signature key is associated with a fixed time reference that is stored in a public key certificate also containing the public verification key. Upon receiving the document, the TSA creates a time stamp receipt by computing a time difference between the time reference associated with the signature key and the time the document was received. The time difference is appended to the document to create a time stamp receipt and the receipt is then signed by the TSA and transmitted to the requestor.

Abstract: Methods, systems and computer program products are provided which provide for controlling access to digital data in a file by encrypting the data with a first key, encrypting the first key with a second personal key generated from a password/passphrase associated with the file and further encrypting the encrypted first key with a control key which is managed by the system. In certain embodiments, user authentication may also be provided by issuing a ticket which is utilized to create, access and administer the files in the system.

Abstract: Methods, systems and computer program products are provided which generate an RSA cryptographic value by obtaining user specific information about a user and determining a user specific range of values based on the user specific information. The potential range of RSA prime values is divided into at least two subintervals and the user specific range of values mapped onto a first of the at least two subintervals. A first user-dependent RSA prime is then selected from the range of RSA prime values in the first subinterval corresponding to the mapped user specific range of values.

Abstract: Methods, systems and computer program products are provided which allow for generation and authentication of RSA encrypted values by utilizing a combination of entity specific information such as biometric information and by incorporating information about the secret seeds into the cryptographic values p and q utilized to encrypt the information. Thus, authentication of an encrypted message may be achieved without requiring storage of the secret seed values utilized to generate the cryptographic values. Furthermore the present invention assures that users with different entity specific information utilize different p and q values.

Abstract: A secure method for changing a password to a new password when the passwords are being transmitted over a network is presented. The present invention does not require the use of any additional keys (such as symmetric keys or public/private key pairs) to protect the password exchanges. Moreover, the present solution does not require the use of any encryption algorithms (such as DES, RC4/RC5, etc.), it only requires the use of a collision-resistant hash function.

Abstract: A method to exchange and authenticate public cryptographic keys between parties that share a common but secret password, using a pair of random numbers, a pair of Diffie-Hellman public keys computed from the random numbers and the password, a Diffie-Hellman symmetric secret key computed from the Diffie-Hellman public keys and the random numbers, and hashed values of arguments that depend upon these elements.

Abstract: A method to distribute and authenticate public encryption keys. A client concatenates its ID, its public key, and a secret password known to the client and a server, and hashes the result. The client forms an extended concatenation including the ID, the public key, and the hashed value, and sends the extended concatenation to the server. The server reads the ID and public key, and re-computes the hashed value based on its own knowledge of the password. If the received and the computed hashed values are the same, the server concludes that the client's public key is authentic. An analogous process enables the server to distribute its public key, and enables the client to authenticate the server's distributed public key.

Abstract: A method to exchange and authenticate public cryptographic keys between parties that share a common but secret password. The parties exchange public keys, where the public keys are accompanied by hashed values based on the keys, the password, and random numbers. Each party then encrypts its random number using the public key of the other party, and the encryptions are exchanged. Based on the received encryptions and the known password, each party then re-computes the hashed value received from the other party, and compares the re-computed hashed value with the received hashed value. If the two are the same, the public key that accompanied the hashed value is judged authentic.

Abstract: A method for protecting data for access by a plurality of users. A server encrypts data using a master key and a symmetric encryption algorithm. For each authorized user, a key encryption key (KEK) is derived from a passphrase, and the master key is encrypted using the KEK. The server posts the encrypted data and an ancillary file that includes, for each user, a user identifier and the master key encrypted according to the user's KEK. To access the data, a user enters the passphrase into a client, which re-derives the user's KEK, and finds, in the ancillary file, the master key encrypted using the user's KEK. The client decrypts the master key and then decrypts the data. A KEK may be derived from a natural language passphrase by hashing the passphrase, concatenating the result and a predetermined text, hashing the concatenation, and truncating.

Abstract: A method for time stamping a digital document is disclosed. The document originator creates a time stamp receipt by combining the document and a digital time indication. The time stamp receipt is submitted to a time stamping agent having a trusted clock. The time stamping agent optionally validates the time stamp receipt and then computes the age of the time stamp receipt. If valid, the time stamping agent certifies the time stamp receipt by signing the time stamp receipt with a private signature key. The private signature key is selected from a group of signature keys by the time stamping agent based on the computed age of the time stamp receipt.

Abstract: Methods, systems and computer program products are provided which allow for multi-party authentication by receiving a plurality of biometric authentication messages from a corresponding plurality of users. The biometric authentication messages include biometric data corresponding to the user. It is determined if each of the plurality of received biometric authentication messages is a valid message based on the biometric data contained in the biometric authentication messages so as to determine a quantity of valid biometric authentication messages. An indication of authentication is then provided if the quantity of the valid messages of the received plurality of messages is at least an authentication threshold value.

Abstract: Methods, systems and computer program products are provided which generate a cryptographic key utilizing user specific information to generate a user dependent key. The user specific information may be a user identification or biometric information associated with a user. In particular embodiments of the present invention a seed value is modified with biometric information to generate a user dependent key value. In alternative embodiments a key value is hashed with user specific information or user specific information is hashed and then combined with the key value to generate the user dependent key value. In still another embodiment of the present invention the space of potential key values is divided into subspaces and the subspaces assigned based on user specific information. A key value is then generated from the assigned subspace. Thus, the generated key values for different users are guaranteed to be disjoint.

Abstract: Systems, methods and computer program products reduce effective key length of a symmetric key cipher by deriving an intermediate value from an initial key, using a one-way cryptographic function. Predetermined bit locations of the intermediate value are selected to obtain an intermediate key. An intermediate shortened key is derived from the intermediate key by setting predetermined bit locations of the intermediate key to predetermined values. A diffused intermediate shortened key is derived from the intermediate shortened key using the one-way cryptographic function. Predetermined bit locations of the diffused intermediate shortened key are then selected to obtain a shortened key. In first embodiments, the one-way cryptographic function is a one-way hash function. Second embodiments use the symmetric key cipher itself to perform the one-way cryptographic function.

Abstract: An improved methodology and implementing computer system are provided in which sensitive information is selectively masked in order to enable such information to be relatively securely and efficiently transmitted over networks without disclosure of such sensitive information at a transmitting or receiving terminal, or at points along the data transmission network.

Abstract: A method and apparatus for ensuring that a key recovery-enabled (KR-enabled) system communicating with a non-KR-enabled system in a cryptographic communication system transmits the information necessary to permit key recovery by a key recovery entity. In a first embodiment, data is encrypted under a second key K that is generated as a one-way function of a first key K′ and a key recovery block KRB generated on the first key K′. The key recovery block KRB and the encrypted data e(K, data) are transmitted to the receiver, who cannot decrypt the data without regenerating the second key K from the first key K′ and the key recovery block KRB. In a second embodiment, data is encrypted under a second key K that is generated independently of the first key K′. A third key X, generated as a one-way function of the first key K′ and a key recovery block KRB generated on the second key K, is used to encrypt the XOR product Y of the first and second keys K′, K.