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

Namespace:  Rebex.Security.Cryptography
Assembly:  Rebex.Common (in Rebex.Common.dll)

Syntax

Visual Basic
Public Sub Decrypt ( _
	nonce As Byte(), _
	ciphertext As Byte(), _
	authTag As Byte(), _
	plaintext As Byte(), _
	additionalAuthData As Byte() _
)
C#
public void Decrypt(
	byte[] nonce,
	byte[] ciphertext,
	byte[] authTag,
	byte[] plaintext,
	byte[] additionalAuthData
)

Parameters

nonce
Type: array<System..::..Byte>[]()[][]
The 12-byte nonce.
ciphertext
Type: array<System..::..Byte>[]()[][]
The byte array that contains cipher text that will be decrypted.
authTag
Type: array<System..::..Byte>[]()[][]
The 16-byte array that contains authentication tag.
plaintext
Type: array<System..::..Byte>[]()[][]
The byte array in which the resulting plain text will be stored.
additionalAuthData
Type: array<System..::..Byte>[]()[][]
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

 Copy imageCopy Code
            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.
            
            }

Version Information

.NET Compact Framework

Supported in: 3.9, 3.5

See Also