1. A method to detect a coating on a fluid sensor, comprising:
determining a fluid sample type;
performing, via the fluid sensor, at least one fluid sample measurement; and
determining, based on the determination of the fluid sample type, whether the at least one fluid sample measurement is indicative of a film coating on a fluid sensor interface with the sampled fluid.
2. A method as defined in claim 1, further comprising initiating a process to remove the coating in response to determining that the at least one fluid sample measurement is indicative of the coating.
3. A method as defined in claim 1, wherein determining a fluid sample type comprises determining whether the fluid sample is a gas, and wherein performing at least one fluid sample measurement comprises measuring a fluid sample for at least one of an optical density parameter, a color absorption parameter, a scattering parameter, a water fraction parameter, a reflection parameter or a fluorescence parameter.
4. A method as defined in claim 3, wherein determining whether the fluid sample is a gas comprises measuring a gasoil ratio and determining whether the gasoil ratio is within a predetermined range.
5. A method as defined in claim 4, wherein determining whether the at least one fluid sample measurement is indicative of the coating comprises comparing the optical density parameter and the color absorption parameter to corresponding threshold values typical of gas.
6. A method as defined in claim 1, wherein determining whether there is a coating on the sensor is based on the at least one fluid sample measurement being indicative of a first result that is contradictory to the determined sample fluid type.
7. A method as defined in claim 6, wherein the at least one fluid sample measurement is obtained with an optical reflectionfluorescence sensor or an optical spectrometer.
8. A method as defined in claim 1, wherein performing, via the fluid sensor, at least one fluid sample measurement comprises measuring a plurality of color absorption parameters for each of a plurality of wavelengths.
9. A method as defined in claim 8, wherein determining whether the at least one fluid sample measurement is indicative of the coating comprises determining that a first color absorption parameter associated with a first wavelength corresponds to a higher optical density than an optical density associated with a second color absorption parameter associated with a second wavelength that is longer than the first wavelength.
10. A method as defined in claim 8, wherein determining whether the at least one fluid sample measurement is indicative of the coating comprises determining that the plurality of color absorption parameters correspond to an absorption pattern of a substance indicative of the coating substance.
11. A method as defined in claim 1, wherein determining whether the at least one sample fluid measurement is indicative of the coating comprises determining whether the at least one measured parameter is within a range of values determined by the fluid type.
12. A method as defined in claim 1, further comprising pumping the fluid sample into a fluid analyzer and wherein determining whether the at least one fluid sample measurement is indicative of the coating comprises determining that the at least one fluid sample measurement is substantially unresponsive to the pumping of the fluid sample.
13. A method as defined in claim 1, wherein determining the fluid sample type comprises performing, via a second fluid sensor, a second fluid sample measurement.
14. A method as defined in claim 1 performed while drilling.
15. An apparatus to detect a coating on a fluid sensor, comprising:
a fluid sensor to measure at least one fluid sample parameter; and
a processing unit to determine a fluid sample type, and whether the at least one fluid sample parameter is indicative of a film coating on a fluid sensor interface with the sampled fluid based on the determination of the fluid sample type.
16. An apparatus as defined in claim 15, wherein the fluid sensor is to measure a gasoil ratio, and the processing unit is to determine whether the fluid sample type is a gas by determining whether the gasoil ratio is within a predetermined range.
17. An apparatus as defined in claim 16, wherein the fluid sensor is to measure an optical density parameter and a color absorption parameter and the processing unit is to determine that the coating is on the sensor based on at least one of an optical density parameter and a color absorption parameter.
18. A method to detect a coating on a window of a fluid analyzer, comprising:
measuring an optical density parameter of a fluid sample;
measuring a color absorption parameter of the fluid sample for each of a plurality of color channels;
determining a gasoil ratio of the fluid sample; and
determining that there is a coating on the window of the fluid analyzer based on two or more of the optical density parameter, the color absorption parameters, and the gasoil ratio of the fluid sample.
19. A method as defined in claim 18, further comprising determining a water fraction of the fluid sample and comparing the water fraction to a predetermined threshold and wherein determining that there is a coating on the window is further based on the comparison.
20. A method as defined in claim 18, further comprising determining a reflectionfluorescence parameter associated with the fluid sample and wherein determining that there is a coating on the window is further based on the reflectionfluorescence parameter.
21. A method as defined in claim 18, wherein determining that there is a coating on the window is further based on at least two of the parameters having contradictory indications.
22. A method as defined in claim 18 further comprising:
performing a first comparison of the optical density parameter with a predetermined value;
performing a second comparison of color absorption parameters with a predetermined color absorption pattern; and
wherein determining that there is a coating on the window of the fluid analyzer is based on the first and second comparisons.
23. A method as defined in claim 22, wherein performing a second comparison of color absorption parameters with a predetermined color absorption pattern comprises determining whether optical density decreases as wavelength increases.
24. A method as defined in claim 18, further comprising pumping the fluid sample into the fluid analyzer and wherein determining there is a coating on the window comprises determining that at least one of the optical density parameter or the water fraction parameter is substantially unresponsive to the pumping of the fluid sample.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An order-preserving encryption system comprising:
encryption unit configured to generate, upon receiving a plaintext as input, an order-preserved cipher in accordance with a predetermined probability distribution generated based on a value determined from the plaintext and on one of a set generated from a plaintext space included in a secret key using a uniform distribution and a key to a predetermined pseudorandom function, the probability distribution representing a conditional probability as a binomial distribution.
2. The order-preserving encryption system according to claim 1, further comprising:
key generation unit configured to generate a first set S comprising elements selected from a plaintext space uniformly at random and generating a second set L comprising a uniform random number as a function of the first set S to generate data comprising the first set S and the second set S as a secret key; wherein
upon receiving a plaintext as input, based on the secret key, the encryption unit calculates a count C\u2033 of elements in the second set L corresponding to an element having a value of not more than a value MB determined from the plaintext, of the elements in the first set S to determine the count C\u2033 as a first value that follows the predetermined probability distribution, calculates a count C\u2032 determined from a count of elements in the plaintext space to determine the count C\u2032 as a second value that follows the predetermined probability distribution, and adds the second value C\u2032 to the first value C\u2033 to generate an order-preserved cipher OPEPart.
3. The order-preserving encryption system according to claim 1, further comprising:
key generation unit configured to generate a key to a predetermined pseudorandom function as a secret key; wherein
upon receiving a plaintext as input, based on the secret key, the encryption unit calculates a value MB determined from the plaintext, obtains a value MBNum by a bisection method that defines the value MB as an accuracy of an approximate solution to determine the value MBNum as a first value that follows the predetermined probability distribution, and obtains a value MBVal by a bisection method that defines the first value MBNum as an accuracy of an approximation solution to determine the value MBVal as a second value that follows the predetermined probability distribution to generate an order-preserved cipher OPEPart using the second value MBVal,
the bisection method that obtains the first value MBNum uses a binomial distribution to calculate a value MidNum in a middle Mid between an upper limit High and a lower limit Low of the bisection method based on the upper limit High, the lower limit Low, and values HighNum and LowNum at the upper limit High and the lower limit Low,
the bisection method that obtains the second value MBVal uses a binomial distribution to calculate a value MidVal in a middle MidNum between an upper limit HighNum and a lower limit LowNum of the bisection method based on the upper limit HighNum, the lower limit LowNum, and values HighVal and LowVal at the upper limit HighNum and the lower limit LowNum, and
the binomial distribution used for each of the bisection method that obtains the first value MBNum and the bisection method that obtains the second value MBVal is generated using a pseudorandom number obtained by inputting the secret key to the pseudorandom function.
4. The order-preserving encryption system according to claim 2, wherein
the key generation unit generates not only the secret key but also a symmetric key for symmetric-key cryptography and a MAC key for a message authenticator,
upon receiving a plaintext as input, the encryption unit generates the order-preserved cipher OPEPart using the secret key, encrypts the plaintext by a symmetric encryption scheme using the symmetric key to generate a cipher SymPart, and adds a message authenticator MACPart generated using the MAC key to a complex cipher formed by a combination of the cipher OPEPart and the cipher SymPart to generate a cipher text Cipher, and
the order-preserving encryption system further comprises:
decryption unit configured to reconstruct, upon receiving the cipher text Cipher generated by the encryption unit, a cipher OPEPart, a cipher SymPart, and a message authenticator MACPart from the cipher text Cipher, checking validity of the reconstructed message authenticator MACPart using the MAC key and a complex cipher formed by a combination of the reconstructed cipher OPEPart and the reconstructed cipher SymPart, and, when the reconstructed message authenticator MACPart is determined to be valid, decrypting the reconstructed cipher SymPart using the symmetric key to obtain a plaintext.
5. The order-preserving encryption system according to claim 1, wherein letting p be a real number, the predetermined probability distribution takes 0 with a probability p and 1 with a probability 1\u2212p.
6. An encryption device comprising:
encryption unit configured to generate, upon receiving a plaintext as input, an order-preserved cipher in accordance with a predetermined probability distribution generated based on a value determined from the plaintext and on one of a set generated from a plaintext space included in a secret key using a uniform distribution and a key to a pseudorandom function, the probability distribution representing a conditional probability as a binomial distribution.
7. A database system comprising:
encryption unit configured to generate, upon receiving a plaintext as input, an order-preserved cipher OPEPart in accordance with a predetermined probability distribution generated based on a value determined from the plaintext and on one of a set generated from a plaintext space included in a secret key using a uniform distribution and a key to a pseudorandom function, the probability distribution representing a conditional probability as a binomial distribution;
data storage unit configured to store the cipher OPEPart generated by the encryption unit as data; and
size comparison unit configured to determine a size of a content of the data stored in the data storage unit relative to an arbitrary plaintext M; wherein
the size comparison unit determines a size of the content of the data relative to an arbitrary plaintext M by comparing a size of the data to be determined with a cipher OPEPart_M for the plaintext M having undergone order-preserving encryption by the encryption unit.
8. The database system according to claim 7, further comprising:
encryption unit configured to generate, upon receiving a plaintext as input, an order-preserved cipher OPEPart in accordance with a predetermined probability distribution generated based on a value determined from the plaintext and on one of a set generated from a plaintext space included in a secret key using a uniform distribution and a key to a pseudorandom function, the probability distribution representing a conditional probability as a binomial distribution, encrypting the plaintext by a symmetric encryption scheme using a symmetric key to generate a cipher SymPart, and adding a message authenticator MACPart generated using a MAC key to a complex cipher formed by a combination of the cipher OPEPart and the cipher SymPart to generate a cipher text Cipher;
decryption unit configured to reconstruct, upon receiving the cipher text Cipher, a cipher OPEPart, a cipher SymPart, and a message authenticator MACPart from the cipher text Cipher, checking validity of the reconstructed message authenticator MACPart using the MAC key and a complex cipher formed by a combination of the reconstructed cipher OPEPart and the reconstructed cipher SymPart, and, when the reconstructed message authenticator MACPart is determined to be valid, decrypting the reconstructed cipher SymPart using the symmetric key to obtain a plaintext;
data storage unit configured to store the cipher text Cipher generated by the encryption unit as data; and
size comparison unit configured to determine a size of a content of the data stored in the data storage unit relative to an arbitrary plaintext M; wherein
the size comparison unit determines a size of the content of the data relative to an arbitrary plaintext M by comparing a size of the cipher OPEPart reconstructed from the data to be determined with a cipher OPEPart_M for the plaintext M having undergone order-preserving encryption by the encryption unit.
9. An order-preserving encryption method comprising:
generating one of data including a set generated from a plaintext space using a uniform distribution and a key to a predetermined pseudorandom function to obtain a secret key; and
upon receiving a plaintext as input, generating an order-preserved cipher in accordance with a predetermined probability distribution generated based on a value determined from the plaintext and on one of the set included in the secret key and the key to the predetermined pseudorandom function, the probability distribution representing a conditional probability as a binomial distribution.
10. An order-preserving encryption program for causing a computer to execute:
processing of, upon receiving a plaintext as input, generating an order-preserved cipher in accordance with a predetermined probability distribution generated based on a value determined from the plaintext and on one of a set generated from a plaintext space included in a secret key using a uniform distribution and a key to a pseudorandom function, the probability distribution representing a conditional probability as a binomial distribution.