EVP_CipherInit_ex2() and EVP_CipherUpdate() return 1 for success and 0 for failure.
EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success.
-EVP_Cipher() returns the amount of encrypted / decrypted bytes, or -1
-on failure if the flag B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is set for the
-cipher. EVP_Cipher() returns 1 on success or 0 on failure, if the flag
+EVP_Cipher() returns 1 on success or 0 on failure, if the flag
B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is not set for the cipher.
+EVP_Cipher() returns the number of bytes written to I<out> for encryption / decryption, or
+the number of bytes authenticated in a call specifying AAD for an AEAD cipher, if the flag
+B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is set for the cipher.
EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure.
To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(),
EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output
-parameter I<out> set to B<NULL>.
+parameter I<out> set to B<NULL>. In this case, on success, the parameter
+I<outl> is set to the number of bytes authenticated.
When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal()
indicates whether the operation was successful. If it does not indicate success,