DecryptAndVerify Method
DecryptAndVerify(ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, ReadOnlySpan<Byte>, Span<Byte>, ReadOnlySpan<Byte>)
Decrypt the ciphertext using AES-GCM with the given
keyData, nonce, and associatedData. Verify the
authentication tag in the tag Span. Place the resulting
decrypted data into the plaintext Span. Return the result of
the authentication verification.
bool DecryptAndVerify(ReadOnlySpan<byte> keyData, ReadOnlySpan<byte> nonce, ReadOnlySpan<byte> ciphertext, ReadOnlySpan<byte> tag, Span<byte> plaintext, ReadOnlySpan<byte> associatedData)Parameters
| Type | Name | Description |
|---|---|---|
| System.ReadOnlySpan<System.Byte> | keyData | The key data that will be used to decrypt, either 16, 24, or 32 bytes. |
| System.ReadOnlySpan<System.Byte> | nonce | The 12-byte "IV". A GCM nonce should be random bytes and should be different for each key. |
| System.ReadOnlySpan<System.Byte> | ciphertext | The data to decrypt. |
| System.ReadOnlySpan<System.Byte> | tag | The 16-byte authentication tag computed during encryption. This is the value this method will authenticate. |
| System.Span<System.Byte> | plaintext | Where the decrypted data will be placed. |
| System.ReadOnlySpan<System.Byte> | associatedData | The "extra" data used to compute the authentication tag. |
Returns
A boolean, true if the authentication tag is verified and
false if it is not.
Exceptions
| Type | Condition |
|---|---|
| System.Security.Cryptography.CryptographicException | The key data is not a valid length. |
| System.ArgumentException | One of the arguments was not valid (e.g. tag is not exactly 16 bytes). |
Remarks
The key data must be either 128, 192, or 256 bits (16, 24, or 32 bytes).
The nonce must be exactly 12 bytes, and the tag must be exactly 16
bytes. The plaintext result will be the same length as the
ciphertext. Note that this method will throw an exception if
plaintext.Length is not exactly ciphertext.Length.
If the input tag matches the tag computed during decryption, this
method will return true. If the input tag does not match the
tag computed during decryption, this method will return false.
In this case, the method will still fill the plaintext buffer
with the decrypted data.