US4375579A
Expired / Lapsed
US
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Database encryption and decryption circuit and method using subkeys
Assignee: Wisconsin Alumni Research Foundation
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Filing: 1980-01-30
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Granted: 1983-03-01
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Expires: 2000-01-30
Abstract
Abstract An encryption and decryption circuit and method using subkeys which is therefore particularly useful for the encryption and decryption of database information. Each data field has a corresponding write key and a different read key. A database record is encrypted by multiplying each field by its corresponding write key and adding up all such products modulo the product of all read keys. The read keys must be prime numbers and the write keys must satisfy a certain relationship with respect to the read keys. A database record may have a single field decrypted by dividing the encrypted record by the read key for that field and taking the remainder. The security of each field may thereby be individually controlled without compromising the security of the entire record.
Inventors
- 👤 George I. Davida
- 👤 David L. Wells
- 👤 John B. Kam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:11
CPC Classifications
G; G06; G06F; G06F21/00; G06F21/70; G06F21/71; G06F21/72; G06F21/60; G06F21/62; G06F21/6209
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
216 words
A method for encryption of a data record consisting of a plurality of fields, f i , and for decryption of a field, f i , from the encrypted record, comprising the steps of: choosing a read key, d i , and write key, e i , corresponding to each field, i, such that each d i is a prime number, D is the product of all d i and each e i is chosen such that e i =1 modulo d i , and e i =0 modulo d j for all j≠i; multiplying each of said plurality of fields by said corresponding key field, e i , to yield an intermediate product; summing all of said intermediate products modulo D to yield an encrypted version of said data record; decrypting a field f i from said encrypted version of said data record by dividing said encrypted version of said data record by said read key d i corresponding to said field f i to yield a decrypted version of said field f i ; concatenating each of said plurality of fields, f i , with a randomly chosed number prior to multiplication by said corresponding key field; and removing said randomly chosen number from said decrypted version of said field f i after decryption.
Claim 2
Independent Claim
216 words
A method for encryption of a data record consisting of a plurality of fields, f i , and for decryption of a field, f i , from the encrypted record, comprising the steps of: choosing a read key, d i , and write key, e i , corresponding to each field, i, such that each d i is a prime number, D is the product of all d i and each e i is chosen such that e i =1 modulo d i , and e i =0 modulo d j for all j≠i; multiplying each of said plurality of fields by said corresponding key field, e i , to yield an intermediate product; summing all of said intermediate products modulo D to yield an encrypted version of said data record; decrypting a field f i from said encrypted version of said data record by dividing said encrypted version of said data record by said read key d i corresponding to said field f i to yield a decrypted version of said field f i ; concatenating each of said plurality of fields, f i , with a randomly chosed number prior to multiplication by said corresponding key field; and removing said randomly chosen number from said decrypted version of said field f i after decryption.
Claim 3
Independent Claim
214 words
A method for encryption of a data record consisting of a plurality of fields, f i , and for decryption of a field, f i , from the encrypted record, comprising the steps of: choosing a read key, d i , and write key, e i , corresponding to each field, i, such that each d i is a prime number, D is the product of all d i and each e i is chosen such that e i =1 modulo d i , and e i =0 modulo d j for all j≠i; multiplying each of said plurality of fields by said corresponding key field, e i , to yield an intermediate product; summing all of said intermediate products modulo D to yield an encrypted version of said data record; decrypting a field f i from said encrypted version of said data record by dividing said encrypted version of said data record by said read key d i corresponding to said field f i to yield a decrypted version of said field f i ; concatenating each of said plurality of fields, f i , with a signature field prior to multiplication by said corresponding key field; and removing said signature field from said decrypted version of said field f i after decryption.
Claim 4
Independent Claim
214 words
A method for encryption of a data record consisting of a plurality of fields, f i , and for decryption of a field, f i , from the encrypted record, comprising the steps of: choosing a read key, d i , and write key, e i , corresponding to each field, i, such that each d i is a prime number, D is the product of all d i and each e i is chosen such that e i =1 modulo d i , and e i =0 modulo d j for all j≠i; multiplying each of said plurality of fields by said corresponding key field, e i , to yield an intermediate product; summing all of said intermediate products modulo D to yield an encrypted version of said data record; decrypting a field f i from said encrypted version of said data record by dividing said encrypted version of said data record by said read key d i corresponding to said field f i to yield a decrypted version of said field f i ; concatenating each of said plurality of fields, f i , with a signature field prior to multiplication by said corresponding key field; and removing said signature field from said decrypted version of said field f i after decryption.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-28 | 1986-08-30 | 1987-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-28 | 1990-08-30 | 1991-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-28 | 1994-08-30 | 1995-03-01 | $7700.00 | Window Closed / Lapsed |