ChaCha20Poly1305IETF

Decrypt the plaintext using the chacha function.

Using the DJB ciphers, encryption and decryption are the same operation applied. simply in reverse, thus, the init parameter in the StreamCipher is irrelevant.

We assume the ciphertext is of the form cipherText || block Thus, it must have a minimum size of at least one.

Decrypt the plaintext using the chacha function.

Using the DJB ciphers, encryption and decryption are the same operation applied. simply in reverse, thus, the init parameter in the StreamCipher is irrelevant.

We assume the ciphertext is of the form cipherText || block Thus, it must have a minimum size of at least one.

Run the empty block on the cipher, run the encryption algorithm (which is essentially decryption) and compare the tag computed from the original ciphertext.

Decrypt the plaintext using the chacha function.

Run an empty block of 64 bytes through the cipher to generate the Poly1305 key. Decrypt the plaintext, generate the authentication tag and compare it to the supplied tag.

Encrypt the plaintext using the chacha function.

Run an empty block of 64 bytes through the cipher to generate the Poly1305 key. Encrypt the plaintext, then return the block and the tag concatenated like:

cipherText || block

Encrypt the plaintext using the chacha function.

Run an empty block of 64 bytes through the cipher to generate the Poly1305 key. Encrypt the plaintext, then return the block and the tag concatenated like:

cipherText || block

Encrypt the plaintext using the chacha function.

Run an empty block of 64 bytes through the cipher to generate the Poly1305 key. Encrypt the plaintext, then return the block and the tag in a separate fashion.

Encrypt the plaintext using the chacha function.

Run an empty block of 64 bytes through the cipher to generate the Poly1305 key. Encrypt the plaintext, then return the block and the tag in a separate fashion.