The present invention is a cryptographic method that uses at least one component of a modified fractional Fourier transform kernel a user-definable number of times. For encryption, a signal is received; at least one encryption key is established, where each encryption key includes at least four user-definable variables that represent an angle of rotation, a time exponent, a phase, and a sampling rate; at least one component of a modified fractional Fourier transform kernel is selected, where each component is defined by one of the encryption keys; and the signal is multiplied by the at least one component of a modified fractional Fourier transform kernel selected. For decryption, a signal to be decrypted is received; at least one decryption key is established, where each decryption key corresponds with, and is identical to, an encryption key used to encrypt the signal; at least one component of a modified fractional Fourier transform kernel is selected, where each component corresponds with, and is identical to, a component of a modified fractional Fourier transform kernel used to encrypt the signal; and dividing the signal by the at least one component of a modified fractional Fourier transform kernel selected.Cryptographic method using modified fractional fourier transform kernel671803806/04/200427/07/200020041,349Cusmariu; AdolfUS Patent and Trademark OfficeGoogle Patent Searchpatentimages.storage.googleapis.com/US6718038B1/US06718038-20040406-D00000.pngUniquemodified fractional fouriercomponentkernelencryption keysignalcryptographic methoddecryptionuser-definable variablessampling ratepresent invention