ChaCha20Poly1305.Decrypt Method

Namespace: Rebex.Security.Cryptography

Assembly: Rebex.Security.dll (version 7.0.9313)

Decrypt(Byte[], Byte[], Byte[], Byte[], Byte[])

Decrypts ciphertext using the secret key and nonce, stores the result to the ciphertext and validates authTag.

Declaration

public void Decrypt(byte[] nonce, byte[] ciphertext, byte[] authTag, byte[] plaintext, byte[] additionalAuthData = null)

Parameters

Type	Name	Description
Byte[]	nonce	The 12-byte nonce.
Byte[]	ciphertext	The byte array that contains cipher text that will be decrypted.
Byte[]	authTag	The 16-byte array that contains authentication tag.
Byte[]	plaintext	The byte array in which the resulting plain text will be stored.
Byte[]	additionalAuthData	Optional (can be null) byte array that contains additional authenticated data (AAD). This byte array should contain the exactly same additional authenticated data that were provided to previous encryption operation; otherwise decryption fails.

Remarks

When the validation of the authentication tag check fails, then CryptographicException is thrown and ciphertext is not decrypted.

Examples

using (var chacha20Poly1305 = new ChaCha20Poly1305(key))
{
   //Decrypt data. Use the same nonce, same additional authentication data, and use the authTag from the previous encrypt operation.
   chacha20Poly1305.Decrypt(nonce, cipherText, authTag, decryptedData, aaaData);
   //After a successful call decryptedData contains decrypted data.

}