ascon-go

README

Ascon cipher

Ascon cipher in idiomatic Go using interfaces by the standard library. Reference:

• The proposed v1.2 NIST specification.
• Ascon PRF, MAC, and Short-Input MAC.

Don't expect too much of this. There's no guarentee that this is actually safe, use at your own risk. It might delete your files if the cat in the void meows.

General overview

• ascon-permutation: Internal package that implements the Ascon permutation.
• ascon-aead: Package that exports cipher.AEAD interface for Ascon-128, Ascon-128a and Ascon-80pq AEAD modes.
• ascon-hash: Package that exports hash.Hash interface for Ascon-Hash and Ascon-Hasha, exports ascon_hash.Xof interface for Ascon-Xof and Ascon-Xofa.
• ascon-prf: Package that exports hash.Hash interface for Ascon-Mac.

Examples

Encrypting with Ascon:

// Can be swapped with New128a or New80pq for Ascon-128a and Ascon-80pq respectively.
c, err := ascon_aead.New128(key)
if err != nil {
    // [...]
}

cipherText := c.Seal(nil, nonce, cipherText, nil)

Decrypting with Ascon:

// Can be swapped with New128a or New80pq for Ascon-128a and Ascon-80pq respectively.
c, err := ascon_aead.New128(key)
if err != nil {
    // [...]
}

plainText, err := c.Open(nil, nonce, cipherText, nil)
if err != nil {
    // [...]
}

Hashing with Ascon:

message := []byte("Hello, world")

// Can be swapped with Suma for Ascon-Hasha.
messageDigest := ascon_hash.Sum(message)

Hash of file with Ascon:

f, err := os.Open("README.md")
if err != nil {
    // [...]
}
defer f.Close()

// Can be swapped with Newa for Ascon-Hasha.
h := ascon_hash.New()
h.Write(f)
fileHash := h.Sum(nil)

XOF with Ascon:

message := []byte("Hello, world")
longHash := make([]byte, 1024)

// Can be swapped with NewXofa for Ascon-Xofa.
xof := ascon_hash.NewXof()
xof.Write(message)
xof.Read(longHash) // Produces a hash with a length of 1024 bytes.

Generate MAC tag with Ascon:

key := []byte("Ascon-Mac keyzzz")
message := []byte("Hello, world")

mac, err := ascon_prf.NewMac(key)
if err != nil {
    // [...]
}
mac.Write(message)
tag := mac.Sum(nil)

Verify MAC tag with Ascon:

key := []byte("Ascon-Mac keyzzz")
message := []byte("Hello, world")
tag := []byte{149, 86, 87, 32, 71, 31, 182, 39, 220, 208, 135, 131, 103, 176, 255, 44}

ok, err := ascon_prf.ValidateMac(message, tag, key)
if err != nil {
    // [...]
}
fmt.Println(ok) // Result: true

License

The code is licensed under the MIT License. Files in the testdata directory is licensed differently.