An implementation based on NIST.SP.800-185

Algorithms:

• SHA-3 derived function KMACXOF256
• ECDHIES encryption and Schnorr signatures
• DHIES encryption and Schnorr signatures with elliptic curves

Objective: implement (in Java) a library and an app for asymmetric encryption and digital signatures at the 256-bit security level

Developed By:

Yudong Lin:

• The overall structure of the program, including but not limited to Glossary functions and ECDHIES encryption, and so on.
• The implementation of elliptic curves service module.
• Bug fixes and finalize the implementation of Ed448-Goldilocks

Brian M LeSmith:

• The implementation of cSHAKE256
• The implementation of Ed448-Goldilocks

What this program will do:

KMACXOF256 and ECDHIES encryption:

1. Compute a plain cryptographic hash of a given file.

2. Compute a plain cryptographic hash of text input by the user directly to the app (instead of having to be read from a file).

3. Compute an authentication tag (MAC) of a given file under a given passphrase.

4. Compute an authentication tag (MAC) of text input by the user directly to the app (instead of having to be read from a file) under a given passphrase.

5. Encrypt a given data file symmetrically under a given passphrase.

6. Decrypt a given symmetric cryptogram under a given passphrase.

DHIES encryption and Schnorr signatures with elliptic curves

1. Generate an elliptic key pair from a given passphrase and write the public key to a file.
2. Encrypt the private key from that pair under the given password and write it to a different file as well.
3. Encrypt a data file under a given elliptic public key file and write the ciphertext to a file.
4. Encrypt text input by the user directly to the app instead of having to read it from a file (but write the ciphertext to a file).
5. Decrypt a given elliptic-encrypted file from a given password and write the decrypted data to a file.
6. Sign a given file from a given password and write the signature to a file.
7. Sign text input by the user directly to the app instead of having to read it from a file (but write the signature to a file).
8. Verify a given data file and its signature file under a given public key file.

How to use:

SHA-3:

Compute a plain cryptographic hash:

-h -f <file path> -- the program will compute a plain cryptographic hash of the file located on given path

-h -s <string> -- the program will compute a plain cryptographic hash of a given string

-h -- you will be asked to input a string, then the program will compute a plain cryptographic hash of a given string

Compute an authentication tag:

-t -f <file path> -p <passphrase> -- the program will compute an authentication tag of the file located on given path with the given passphrase

-t -f <file path> -- same as above, but you will be prompted to input a passphrase manually

-t -s <string> -p <passphrase> -- the program will compute an authentication tag of a given string with the given passphrase

-t -s <string> -- same as above, but you will be prompted to input a passphrase manually

-t -- you will be asked to input a string and a passphrase, then the program will compute an authentication tag of a given string with the given passphrase

Encryption:

-e -f <input file path> -p <passphrase> -o <output file path> -- the program will encrypt the file located on given path with the given passphrase, and then save to given location

-e -f <input file path> -o <output file path> -- same as above, but you will be prompted to input a passphrase manually

-e -f <input file path> -- same as above, but the encrypted data will only be printed to console, and not save to local disk.

Decryption:

-d -f <file path> -p <passphrase> -- the program will decrypt the file located on given path with the given passphrase

-d -f <file path> -- same as above, but you will be prompted to input a passphrase manually

Elliptic curves:

Generate an elliptic key pair:

-eck -p <passphrase> -o <public key output path> -o2 <private key output path> -- generate an elliptic key pair from a given passphrase and write the public key and encrypted private key to given location.

-eck -o <public key output path> -o2 <private key output path> -- same as above, but you will be prompted to input a passphrase manually

-eck -o <public key output path> -- same as above, but the private key will only be printed to console, and will not be saved to local disk.

-eck -- same as above, but the public key will only be printed to console, and will not be saved to local disk.

Encryption using elliptic public key:

-ece -f <input file path> -keyp <key file path> -o <ciphertext save to path> -- the program will encrypt the file located on given path with the given public key, and then save to given location

-ece -keyp <key file path> -o <ciphertext save to path> -- same as above, but you will be asked to input a string which will be encrypted and save to given location.

-ece -keyp <key file path> -- same as above, but the encrypted data will only be printed to console, and will not be saved to local disk.

Decryption:

-ecd -f <input file path> -p <passphrase> -o <output file path> -- the program will decrypt the file located on given path with the given passphrase, and then save to given location

-ecd -f <input file path> -o <output file path> -- same as above, but you will be prompted to input a passphrase manually

-ecd -f <input file path> -- same as above, but the encrypted data will only be printed to console, and not save to local disk.

Sign:

-ecs -f <input file path> -p <passphrase> -o <output file path> -- the program will sign the file located on given path with the given passphrase, and write the signature to give output path.

-ecs -p <passphrase> -o <output file path> -- same as above, but you will be prompted to input a string which will be signed and used to generate the signature

-ecs -o <output file path> -- same as above, but you will be prompted to input a passphrase manually

-ecs -- same as above, but the signature will only be printed to console, and will not be saved to local disk.

Verify:

-ecv -f <input data file path> -o <signature file path> -keyp <public key file path> -- Verify a given data file and its signature file under a given public key file.

Please Note:

The mode argument such as "-h" or "-t" has to be entered as the first argument! The other arguments can be entered in different orders, but following the order listed above are highly recommended!

License

Please check the LICENSE file. You are free to learn and use any part of this repo. However, giving us credits is always a requirement! You are mandated to include an explicit link to this repo! We reserve the right to notify your professor or take legal action if needed.

Credits:

Our implementations is inspired by following repositories or documents:

https://github.com/mjosaarinen/tiny_sha3

NIST.SP.800-185

https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Standards-and-Guidelines/documents/examples/cSHAKE_samples.pdf

Reference used for implementing Ed448-Goldilocks:

https://ed448goldilocks.sourceforge.net/spec/

https://github.com/otrv4/ed448/tree/master

https://github.com/Realiserad/elliptic-curve-cryptography