(PECL rnp >= 0.1.1)
rnp_op_sign — Perform signing operation on a binary data, return embedded signature(s)
ffiThe FFI object returned by rnp_ffi_create().
dataData to be signed.
keys_fp
      Array with key fingerprints. At least one key must be provided.
      Keys should be present in ffi.
     
optionsAn associative array with options.
| Key | Data type | Description | 
|---|---|---|
| "compression_alg" | string | Compression algorithm. Both "compression_alg"and"compression_level"must be set in order to enable data compression. | 
| "compression_level" | integer | Compression level, 0-9. 0 disables compression. | 
| "armor" | boolean | Enable ASCII-armored output. Disabled by default. | 
| "hash" | string | Set hash algorithm used during signature calculation. | 
| "creation_time" | integer | Set signature creation time in seconds since Jan, 1 1970 UTC. By default current time is used. | 
| "expiration_time" | integer | Set signature expiration time in seconds since the creation time. 0 value is used to mark signature as non-expiring (default value). | 
| "file_name" | string | Set input file name.Special value _CONSOLE may be used to mark message as 'for your eyes only', i.e. it should not be stored anywhere but only displayed to the receiver. Default is the empty string. | 
| "file_mtime" | integer | Set input file modification date in seconds since Jan, 1 1970 UTC. | 
   Data with embedded signature(s) on success or false on failure.
  
