Encryption and decryption program

• US 20030235307A1
• Filed: 06/09/2003
• Published: 12/25/2003
• Est. Priority Date: 06/13/2002
• Status: Abandoned Application

• Current Assignee: Kazuhiro Miyamoto
• Original Assignee: Kazuhiro Miyamoto
• Inventors: Miyamoto, Kazuhiro
• Application Number:
  US10/457,628
• Publication Number:
  US 20030235307A1
• Time in Patent Office: Days
• US Class Current: 380/269
• CPC Class Codes: H04L 2209/30 Compression, e.g. Merkle-Damgard construction
• CPC Class Codes: H04L 9/002 Countermeasures against attacks on cryptographic mechanisms network architectures or network communication protocols for protection against malicious traffic H04L63/1441
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/14 using a plurality of keys or algorithms

Abstract

A novel hybrid cryptosystem proposed in the present invention comprises a step of removing a part of data from a compressed message to be later encrypted with a symmetric cryptography so as to encrypt a session key and the removed data with a public key, which is an additional step that a conventional hybrid cryptosystem does not have.

Claims

1. A message encryption program for causing a computer to function as:

compression means for compressing binary data;

combining means for combining a plurality of binary data;

removing means for removing a part of data from a compression message obtained by compressing a message entered into the computer by the compression means so as to generate a lacked compression message and removed data;

symmetric key encryption means for encrypting the lacked compression message with a symmetric algorithm using a session key to generate an encryption message;

public key encryption means for encrypting the removed data and the session key with a public key encryption algorithm using a public key by combining them by the combining means so as to generate an encryption block; and

hybrid encryption means for combining the encryption message and the encryption block by the combining means to generate a hybrid encryption message.

2. A program for decrypting the hybrid encryption message generated by the encryption program according to claim 1, said program causing a computer to function as:

decompression means for decompressing the binary data compressed by the compression means;

decomposition means for decomposing the binary data combined by the combining means into the plurality of binary data;

hybrid decryption means for decomposing the hybrid encryption message into the encryption message and the encryption block by the decomposition means;

public key decryption means for decrypting the encryption block with a public key decryption algorithm using a secret key and then decomposing it into the removed data and the session key by the decomposition means;

symmetric key decryption means for decrypting the encryption message into the lacked compression message with a symmetric key decryption algorithm using the session key; and

embedding means for embedding the removed data in the lacked compression message to restore the compression message,

wherein the compression message is decompressed by the decompression means so as to decrypt it into the message entered into the computer.

7. A computer readable recording medium for recording the program according to claim 1 or 2.

3. An apparatus for encrypting a message comprising:

compression means for compressing binary data;

combining means for combining a plurality of binary data;

removing means for removing a part of data from a compression message obtained by compressing a message entered into the apparatus by the compression means so as to generate lacked compression message and removed data;

symmetric key encryption means for encrypting the lacked compression message with a symmetric algorithm using a session key to generate an encryption message;

public key encryption means for encrypting the removed data and the session key with a public key encryption algorithm using a public key by combining them by the combining means so as to generate an encryption block; and

hybrid encryption means for combining the encryption message and the encryption block by the combining means to generate a hybrid encryption message.

4. An apparatus for decrypting the hybrid encryption message generated by the apparatus according to claim 3 into the message entered into the apparatus, comprising:

decompression means for decompressing the binary data compressed by the compression means;

decomposition means for decomposing the binary data combined by the combining means into the plurality of binary data;

hybrid decryption means for decomposing the hybrid encryption message into the encryption message and the encryption block by the decomposition means;

non-public key decryption means for decrypting the encryption block with a public key decryption algorithm using a secret key and then decomposing it into the removed data and the session key by the decomposition means;

symmetric key decryption means for decrypting the encryption message into the lacked compression message with a symmetric key decryption algorithm using the session key; and

embedding means for embedding the removed data in the lacked compression message to restore the compression message,

wherein the compression message is decompressed by the decompression means so as to decrypt it into the message entered into the apparatus.

5. A method for encrypting a message using a computer having:

compression means for compressing binary data; and

combining means for combining a plurality of binary data, comprising the steps of;

removing a part of data from a compression message obtained by compressing a message entered into the computer so as to generate lacked compression message and removed data;

encrypting the lacked compression message with a symmetric algorithm using a session key to generate an encryption message;

encrypting the removed data and the session key with a public key encryption algorithm using a public key by combining them by the combining means to generate an encryption block; and

combining the encryption message and the encryption block by the combining means to generate a hybrid encryption message.

6. A method for decrypting the hybrid encryption message by the method according to claim 5 using a computer having:

decompression means for decompressing the binary data compressed by the compression means; and

decomposition means for decomposing the binary data combined by the combining means into the plurality of binary data, comprising the steps of;

decomposing the hybrid encryption message into the encryption message and the encryption block;

decrypting the encryption block with a public key decryption algorithm using a secret key and then decomposing it into the removed data and the session key;

decrypting the encryption message into the lacked compression message with a symmetric key decryption algorithm using the session key; and

embedding the removed data in the lacked compression message to restore the compression message,

wherein the compression message is decompressed to decrypt it into the message entered into the computer.

8. A method for ensuring secure message exchange over an insecure telecommunication line, comprising the steps of:

encrypting a message using the method according to claim 5 to generate an encryption message;

transmitting the encryption message over a telecommunication line; and

decrypting the encryption message by the method according to claim 6.