[C#]
    TElCustomCryptoKey DecryptKey(byte[] EncKey, int EncKeyStartIndex, int EncKeySize, byte[] EncKeyAlgOID, byte[] EncKeyAlgParams, TElCustomCryptoKey Key, byte[] KeyAlgOID, byte[] KeyAlgParams, TElCPParameters Params, TSBProgressFunc ProgressFunc, Object ProgressData);

[VB.NET]
    Function DecryptKey(ByVal EncKey As Byte(), ByVal EncKeyStartIndex As Integer, ByVal EncKeySize As Integer, ByVal EncKeyAlgOID As Byte(), ByVal EncKeyAlgParams As Byte(), ByVal Key As TElCustomCryptoKey, ByVal KeyAlgOID As Byte(), ByVal KeyAlgParams As Byte(), ByVal Params As TElCPParameters, ByVal ProgressFunc As TSBProgressFunc, ByVal ProgressData As Object) As TElCustomCryptoKey

[Pascal]
    function DecryptKey(EncKey : pointer; EncKeySize : integer; const EncKeyAlgOID, EncKeyAlgParams : ByteArray; Key : TElCustomCryptoKey; const KeyAlgOID, KeyAlgParams : ByteArray; Params : TElRelativeDistinguishedName = nil; ProgressFunc : TSBProgressFunc = nil; ProgressData : pointer = nil) : TElCustomCryptoKey; virtual; abstract;

[C++]
    TElCustomCryptoKeyHandle DecryptKey(void * EncKey, int32_t EncKeySize, const std::vector<uint8_t> &EncKeyAlgOID, const std::vector<uint8_t> &EncKeyAlgParams, TElCustomCryptoKey &Key, const std::vector<uint8_t> &KeyAlgOID, const std::vector<uint8_t> &KeyAlgParams, TElRelativeDistinguishedName &Params, TSBProgressFunc pMethodProgressFunc, void * pDataProgressFunc, void * ProgressData);
    TElCustomCryptoKeyHandle DecryptKey(void * EncKey, int32_t EncKeySize, const std::vector<uint8_t> &EncKeyAlgOID, const std::vector<uint8_t> &EncKeyAlgParams, TElCustomCryptoKey *Key, const std::vector<uint8_t> &KeyAlgOID, const std::vector<uint8_t> &KeyAlgParams, TElRelativeDistinguishedName *Params, TSBProgressFunc pMethodProgressFunc, void * pDataProgressFunc, void * ProgressData);

[PHP]
    TElCustomCryptoKey DecryptKey(TSBPointer|array of byte|string|NULL $EncKey, integer $EncKeySize, array of byte|string|NULL $EncKeyAlgOID, array of byte|string|NULL $EncKeyAlgParams, TElCustomCryptoKey $Key, array of byte|string|NULL $KeyAlgOID, array of byte|string|NULL $KeyAlgParams, TElRelativeDistinguishedName $Params, TSBProgressFunc|callable|NULL $ProgressFunc, TSBPointer|array of byte|string|NULL $ProgressData)

[Java]
    TElCustomCryptoKey decryptKey(byte[] arg0, int arg1, int arg2, byte[] arg3, byte[] arg4, TElCustomCryptoKey arg5, byte[] arg6, byte[] arg7, TElCPParameters arg8, TSBProgressFunc arg9, TObject arg10);