1. A bus connection (1) for connecting a field device (2) to a field bus (3) whereby the bus connection (1) has a circuit (5) for sending and receiving databus signals (RxD, TxD, TRS) and for generating at least one regulated operating voltage (UA1), and the regulated operating voltage (UA1) is generated from a bus voltage (UBus) supplying the field bus (3),
characterized in that a controllable resistor (T1) is provided for generating an additional operating voltage (UA2); circuitry means (OP, R1, R2, R3, R5, Z1, Z2) are provided, controlling the controllable resistor (T1) as a function of the bus voltage (UBus) such that the input voltage (UB) of the circuit (5) is regulated at its minimum required power supply voltage; and the sum of the regulated operating voltage (UA1) and the additional operating voltage (UA2) is supplied to the field device (2) as the power supply voltage (UA).
2. The bus connection (1) according to claim 1,
characterized in that an operational amplifier (OP) to which a reference voltage (URef) derived from the best voltage (UBus) is sent is provided as the circuitry means.
3. The bus connection (1) according to claim 2,
characterized in that the reference voltage (URef) is based on a potential (V+Bus) of the bus voltage (UBus).
4. The bus connection (1) according to claim 2,
characterized in that the reference voltage (URef) is based on the reference potential (GND5) of the circuit (5).
5. The bus connection (1) according to claim 2,
characterized in that the reference voltage (URef) is supplied at a Z-diode (Z1, Z2) which is connected in series with a series resistor (R3, R5).
6. The bus connection (1) according to claim 2,
characterized in that circuitry means (R4, Z4) are provided for limiting the operating voltage (UOP) of the operational amplifier (OP).
7. The bus connection (1) according to claim 1,
characterized in that a bipolar transistor (T1) is provided as the controllable resistor.
8. The bus connection (1) according to claim 1,
characterized in that a field effect transistor (T1) is provided as the controllable resistor.
9. The bus connection (1) according to claim 1,
characterized in that a circuitry means (Z3) preferably a Z-diode is provided for limiting the additional output voltage (UA2).
10. The bus connection (1) according to claim 1,
characterized in that the field device (2) comprises a digital part (10, 11, 12, 13) and a sensor part (6).
11. The bus connection (1) according to claim 10,
characterized in that the sensor part (6) receives the sum of the regulated operating voltage (UA1) and the additional operating voltage (UA2) as the power supply voltage (UA).
12. The bus connection (1) according to claim 10,
characterized in that the digital part of the field device (2) comprises a level converter (10) and a step-down converter (13) to which the sum of the regulated operating voltage (UA1) and the additional operating voltage (UA2) is supplied as the power supply voltage (UA).
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A computer based encryption and decryption system comprising:
(a) means
(i) for determining whether digital input information including as content at least one of a body of a message and a file attachment is encrypted using a cryptographic key, and
(ii) for decrypting the digital input information using a private decryption key of a public key pair
prior to applying policies that analyze the content of the digital input information; and
(b) a policy manager configured to apply the policies, the policies including a virus policy for detecting and eradicating a detected virus;
wherein:
(c) the private decryption key is apart from the content of the digital input information and
(d) decryption is done without using decryption executables contained in a header corresponding to the digital input information when a header is present.
2. The system of claim 1, wherein the means for decrypting decrypts the digital information content to facilitate content analysis prior to allowing subsequent use of the decrypted digital input information on a computer system.
3. The system of claim 1, wherein the means for decrypting decrypts the digital information content to facilitate content analysis prior to allowing subsequent transfer of the decrypted digital input information.
4. The system of claim 1, wherein the means for decrypting uses a private decryption key which has been stored by the system.
5. The system of claim 1, wherein the policy manager performs real time content analysis of the digital input information before allowing the digital input information to be passed to a designated recipient.
6. The system of claim 1, wherein the policy manager is further configured to defer, quarantine, return to sender, or drop the digital input information as a result of the content analysis.
7. A computer based encryption and decryption method, said method comprising the steps of:
(a) determining whether digital input information that includes as content at least one of a body of a message and a file attachment is encrypted;
(b) decrypting the digital input information without using decryption executables included in a header corresponding to the digital input information when a header is present if it is determined that the digital input information is encrypted; and
(c) providing content analysis including performing virus detection to facilitate eradication of a detected virus subsequent to decrypting the digital information.
8. The encryption and decryption method of claim 7, wherein the step of providing content analysis includes decrypting the digital information content to facilitate content analysis prior to allowing subsequent use of the decrypted digital input information on a computer system.
9. The encryption and decryption method of claim 7, wherein the step of providing content analysis includes decrypting the digital information content to facilitate content analysis prior to allowing subsequent transfer of the decrypted digital input information.
10. The encryption and decryption method of claim 7, wherein the step of decrypting includes using a private decryption key which has been stored by the system.
11. The encryption and decryption method of claim 7, further including the step of deferring decrypted information prior to dissemination of the digital input information within the network.
12. The encryption and decryption method of claim 7, wherein the step of providing content analysis includes the step of performing real time content analysis of the digital input information before allowing the digital input information to be passed to a designated recipient.
13. A storage medium comprising:
a program executable by a computing mechanism that facilitates the following steps:
(i) determining whether digital input information that includes as content at least one of a body of a message and a file attachment is encrypted;
(ii) decrypting the digital input information without using decryption executables included in a header corresponding to the digital input information when a header is present if it is determined that the digital input information is encrypted; and
(iii) applying content analysis to the decrypted digital input information prior to allowing use of the decrypted digital input information, wherein content analysis includes performing virus detection to facilitate eradication of a detected virus.
14. The storage medium of claim 13, wherein decrypting includes using a private decryption key which has been stored by the system.
15. The storage medium of claim 13, wherein the program also facilitates decryption operation on the encrypted digital input information to facilitate content analysis prior to transferring of the digital input information for use by a target application.
16. A computer based encryption and decryption system comprising:
(a) means
(i) for determining whether digital input information including as content at least one of a body of a message and a file attachment is encrypted using a cryptographic key, and
(ii) for decrypting the digital input information using a private decryption key of a public key pair prior to applying policies that analyze the content of the digital input information; and
(b) a policy manager configured to apply the policies, the policies including a virus policy for detecting and eradicating a detected virus;
wherein:
(c) the private decryption key is apart from the content of the digital input information and
(d) has been stored by the system for access at the time of decryption.
17. The encryption and decryption system of claim 16, wherein the means for decrypting decrypts the digital information content to facilitate content analysis prior to allowing subsequent transfer of the decrypted digital input information.
18. An encryption and decryption method comprising:
providing content analysis by determining whether digital input information that includes at least one of a file, document and at least part of a body of a message is encrypted and
generating a decryption request to a decryptor to decrypt the encrypted digital input information prior to applying content analysis to facilitate content analysis within the encrypted digital input information; and decrypting the encrypted digital input information prior to completion of the content analysis
wherein content analysis includes performing virus detection to facilitate eradication of a detected virus,
wherein decrypting is done without using decryption executables contained in a header corresponding to the digital input information, if a header is present.