Use of encryption to provide positioning support services

An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause a mobile device at least to perform:

• holding available at least a first decryption key;
• receiving encrypted first positioning support data covering a first service area, wherein said encrypted first positioning support data are decryptable by said first decryption key, wherein said encrypted first positioning support data are configured to enable one or more mobile devices receiving said encrypted first positioning support data and having access to said first decryption key to determine their position within the first service area at least partially based on said encrypted first positioning support data decrypted by the first decryption key, and wherein said first decryption key is one decryption key of a plurality of decryption keys;
• receiving encrypted second positioning support data covering the second service area, wherein at least a second decryption key of said plurality of decryption keys is associated with encrypted second positioning support data covering the first service area, and wherein the encrypted second positioning support data supports positioning of a higher accuracy relative to positioning supported by the encrypted first positioning support data, and wherein the second decryption key is different from the first decryption key;
• obtaining observation information comprising a timing measurement and an angle of arrival;
• decrypting said encrypted first positioning support data using said first decryption key;
• and
• determining a position of said mobile device at least partially based on said first positioning support data and said observation information.

An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause a server at least to perform:

• holding available a plurality of decryption keys;
• assigning at least a first decryption key of said plurality of decryption keys to a mobile device, wherein said first decryption key is useable to decrypt encrypted first positioning support data covering a first service area, and wherein said encrypted first positioning support data is configured to enable one or more mobile devices receiving said encrypted first positioning support data and having access to said first decryption key to determine their position within the first service area at least partially based on said encrypted first positioning support data decrypted by the first decryption key, wherein a second decryption key of said plurality of decryption keys is associated with encrypted second positioning support data covering the first service area, wherein the encrypted second positioning support data supports positioning of a higher accuracy relative to positioning supported by the encrypted first positioning support data, and wherein the second decryption key is different than the first decryption key;
• and
• providing said first decryption key to said mobile device.