Showing papers on "Attribute-based encryption published in 1984"

Method and apparatus for use in public-key data encryption system

Abstract: In an encryption scheme based on the use of a public key having secret factors p and q, additional requirements on p and q are invoked in order to ensure a high level of security. In particular, it is additionally required that a value p+1 have a large prime factor r and that the value r-1 also have a large prime factor r'.

Field Encryption and Authentication

Abstract: Database encryption and authentication at the field level is attractive because it allows projections to be performed and individual data elements decrypted or authenticated. But field based protection is not usually recommended for security reasons: using encryption to hide individual data elements is vulnerable to ciphertext searching; using cryptographic checksums to authenticate individual data elements is vulnerable to plaintext or ciphertext substitution. Solutions to the security problems of field based protection are proposed.

Data processing system having public encryption and private decryption keys

Abstract: A data processing system that provides for the public en­ cryption of software programs while simultaneously protecting against the public decryption and piracy of those programs is comprised of a plurality of microprocessors: each micropro­ cessor has a unique and publicly accessible encryption key for encrypting software programs in a unique fashion for that mi­ croprocessor; each microprocessor further has a unique de­ cryption key for decrypting programs that have been encrypt­ ed with the microprocessor's unique encryption key; the de­ cryption key in each microprocessor is imbedded therein in a fashion which makes the decryption key humanly impercepti­ ble, and is of a type that is not determinable from the publicly accessible encryption key.