Supporting the decryption of encrypted data

An apparatus comprising at least one processor and at least one memory with a program, the at least one memory and the program configured to, with the at least one processor, cause the apparatus to perform the following:

• log on to a second installation with authentication of a user, wherein a first installation is configured to provide a secret key of the user of the apparatus, and wherein the second installation is configured to provide data for the user,
• receive encrypted data from the second installation,
• create a one-time password,
• encrypt the one-time password by means of a public key of the first installation,
• transmit the encrypted one-time password to the second installation and cause the second installation to retrieve the secret key of the user from the first installation by means of the encrypted one-time password and a key identification allocated to the user in the second installation,
• receive the secret key of the user, which was encrypted by the first installation with the one-time password, from the second installation,
• decrypt the secret key of the user by means of the one-time password and
• decrypt the encrypted data by means of the secret key of the user.

A non-transitory computer-readable storage medium which stores a program comprising program instructions, wherein the program instructions when executed by a processor cause an apparatus to perform the following:

• log on to a second installation with authentication of a user, wherein a first installation is configured to provide a secret key of the user of the apparatus, and wherein the second installation is configured to provide data for the user,
• receive encrypted data from the second installation,
• create a one-time password,
• encrypt the one-time password by means of a public key of the first installation,
• transmit the encrypted one-time password to the second installation and cause the second installation to retrieve the secret key of the user from the first installation by means of the encrypted one-time password and a key identification allocated to the user in the second installation,
• receive the secret key of the user, which was encrypted by the first installation with the one-time password, from the second installation,
• decrypt the secret key of the user by means of the one-time password and
• decrypt the encrypted data by means of the secret key of the user.

A method performed by an apparatus of a first installation, wherein a second installation is configured to provide data for a user, the method comprising:

• receiving a key identification and a one-time password, which was generated by an apparatus of a user and encrypted with a public key of the first installation, from the second installation which stores an allocation between users and key identifications,
• reading a secret key of the user, which is encrypted with the key identification, based on the received key identification from a memory of the first installation,
• decrypting the encrypted secret key of the user by means of the key identification,
• decrypting the encrypted one-time password by means of a private key of the first installation,
• encrypting the secret key of the user with the one-time password and
• transmitting the secret key of the user encrypted with the one-time password to the second installation for passing on to the apparatus of the user, in order to enable the user to decrypt encrypted data received from the second installation.

A method performed by an apparatus of a first installation, wherein a second installation is configured to provide data for a user, the method comprising:

• receiving a key identification and a one-time password, which was generated by an apparatus of a user and encrypted with a public key of the first installation, from the second installation which stores an allocation between users and key identifications,
• reading a secret key of the user, which is encrypted with the key identification, based on the received key identification from a memory of the first installation,
• decrypting the encrypted secret key of the user by means of the key identification,
• decrypting the encrypted one-time password by means of a private key of the first installation,
• encrypting the secret key of the user with the one-time password and
• transmitting the secret key of the user encrypted with the one-time password to the second installation for passing on to the apparatus of the user, in order to enable the user to decrypt encrypted data received from the second installation,
• wherein a stored, encrypted secret key of a user is generated beforehand by the apparatus of the first installation as follows:
• receiving a request from the second installation to generate a secret key for a user,
• generating a secret key for a user independent of a user input,
• generating a key identification for the secret key for the user,
• encrypting the secret key for the user with the key identification and
• storing the encrypted secret key in the memory of the first installation for retrieval by an apparatus of the user via the second installation.

An apparatus of a first installation, wherein a second installation is configured to provide data for a user, the apparatus comprising at least one processor and at least one memory with a program, the at least one memory and the program configured to, with the at least one processor, cause the apparatus to perform the following:

• receive a key identification and a one-time password, which was generated by an apparatus of a user and encrypted with a public key of the first installation, from the second installation which stores an allocation between users and key identifications,
• read a secret key of the user, which is encrypted with the key identification, based on the received key identification from a memory of the first installation,
• decrypt the encrypted secret key of the user by means of the key identification,
• decrypt the encrypted one-time password by means of a private key of the first installation,
• encrypt the secret key of the user with the one-time password and
• transmit the secret key of the user encrypted with the one-time password to the second installation for passing on to the apparatus of the user, in order to enable the user to decrypt encrypted data received from the second installation.

An apparatus of a first installation, wherein a second installation is configured to provide data for a user, the apparatus comprising at least one processor and at least one memory with a program, the at least one memory and the program configured to, with the at least one processor, cause the apparatus to perform the following:

• receive a key identification and a one-time password, which was generated by an apparatus of a user and encrypted with a public key of the first installation, from the second installation which stores an allocation between users and key identifications,
• read a secret key of the user, which is encrypted with the key identification, based on the received key identification from a memory of the first installation,
• decrypt the encrypted secret key of the user by means of the key identification,
• decrypt the encrypted one-time password by means of a private key of the first installation,
• encrypt the secret key of the user with the one-time password and
• transmit the secret key of the user encrypted with the one-time password to the second installation for passing on to the apparatus of the user, in order to enable the user to decrypt encrypted data received from the second installation,
• wherein the at least one memory and the program are further configured to cause the apparatus to generate beforehand a stored, encrypted secret key of a user as follows:
• receive a request from the second installation to generate a secret key for a user,
• generate a secret key for a user independent of a user input,
• generate a key identification for the secret key for the user,
• encrypt the secret key for the user with the key identification and
• store the encrypted secret key in the memory of the first installation for retrieval by an apparatus of the user via the second installation.

A non-transitory computer-readable storage medium which stores a program comprising program instructions, wherein the program instructions when executed by a processor cause an apparatus of a first installation to perform the following:

• receive a key identification and a one-time password, which was generated by an apparatus of a user and encrypted with a public key of the first installation, from a second installation, wherein the second installation stores an allocation between users and key identifications and wherein the second installation is configured to provide data for a user,
• read a secret key of the user, which is encrypted with the key identification, based on the received key identification from a memory of the first installation,
• decrypt the encrypted secret key of the user by means of the key identification,
• decrypt the encrypted one-time password by means of a private key of the first installation,
• encrypt the secret key of the user with the one-time password and
• transmit the secret key of the user encrypted with the one-time password to the second installation for passing on to the apparatus of the user, in order to enable the user to decrypt encrypted data received from the second installation.

A system comprising a first installation having an apparatus and a memory for storing a plurality of secret keys of users encrypted with key identifications, as well as a second installation configured to provide data for a user, the apparatus of the first installation comprising at least one processor and at least one memory with a program, the at least one memory and the program configured to, with the at least one processor, cause the apparatus to perform the following:

• receive a key identification and a one-time password, which was generated by an apparatus of a user and encrypted with a public key of the first installation, from the second installation which stores an allocation between users and key identifications,
• read a secret key of the user, which is encrypted with the key identification, based on the received key identification from a memory of the first installation,
• decrypt the encrypted secret key of the user by means of the key identification,
• decrypt the encrypted one-time password by means of a private key of the first installation,
• encrypt the secret key of the user with the one-time password and
• transmit the secret key of the user encrypted with the one-time password to the second installation for passing on to the apparatus of the user, in order to enable the user to decrypt encrypted data received from the second installation.