Time dependence and wavelength selection advanced information encryption method based on visible light response

Abstract

The invention provides an advanced information encryption method based on time dependence and wavelength selection of visible light response, which comprises the following steps of: cutting different CdS / dye / agarose photochromic films into small rods on a common glass or flexible transparent substrate, and pasting according to a pre-designed digital password template to realize information encryption. In the time-dependent information encryption, based on different oxidation kinetics of methylene blue (MB) and methylene green (MG), the time-dependent information encryption is realized by utilizing the color change difference of the methylene blue (MB) and the methylene green (MG) in the air along with time. In wavelength selective information encryption, the MB and the PPS are mixed, and wavelength selective information encryption is realized through different response capabilities of the MB and the PS to light with different wavelengths. According to the information encryption method, the visible light is utilized to drive the photochromic film to prepare the information encryption method, time-dependent and wavelength-selective advanced polymorphic information encryption is realized, the information security can be greatly enhanced, and the method has wide application in the fields of information secrecy, information storage, anti-counterfeiting marks and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of time-dependent and wavelength-selective polymorphic advanced information encryption method based on visible light response, belong to information material technical field. BACKGROUND

[0002] With the vigorous development of information technology, the security of massive data information is more and more widely concerned by the society, so the storage and encryption of information has become the focus of researchers. In recent years, in order to improve the level of information security, people have done a lot of work in the development of information encryption materials. For example, Professor Chen Tao's research group reported a urease-coated polyacrylamide fluorescent hydrogel, which introduced metal ions (Zn 2+ , Al 3+), the gel was treated in urea solution, and the different urease-urea catalytic reaction rates showed time differences in fluorescence weakening, thereby realizing the spatiotemporal regulation of the fluorescence intensity of the hydrogel, and the decryption-self-erasing of multi-level encrypted information was achieved. (Le, X.; Shang, H.; Yan, H.; Zhang, J.; Lu, W.; Liu, M.; Wang, L.; Lu, G.; Xue, Q.; Chen, T. A urease-containing fluorescent hydrogel for transient information storage. Angew. Chem., Int. Ed. 2021, 60, 3640-3646). Professor Tian's group designed a kind of ultraviolet light response self-assembly supramolecular photochromic material, which used the influence of different proportions of host and guest on the rate of photodimerization to show different color changes, successfully introduced the time variable into a dynamic switching system, and realized the time-resolved dynamic encryption / decoding process. (Li, D.; Feng Z.; Han Y.; Chen C.; Zhang Q.; Tian Y. Time-Resolved Encryption via a Kinetics-Tunable Supramolecular Photochromic System. Adv. Sci. 2022, 9, 2104790). Although these encryption materials introduce the time variable, they realize the dynamic regulation of information encryption, but there are still some challenges in the application of these photochromic materials. In these information storage and encryption systems, most of them rely on ultraviolet light to drive the display of encrypted information, and ultraviolet light has the disadvantages of weak penetration, great damage to users and substrate materials, etc. Therefore, compared with ultraviolet light, visible light is considered to be a more friendly light source. In addition, it is more noteworthy that only the visualization of information recorded in one wavelength, and this simple information storage method is limited by the lower security level in application. Therefore, it has great scientific significance to introduce dynamic regulation of photochromic with different spatial dimensions, and realize the dynamic regulation of multi-level information encryption material with time dependence and wavelength selection driven by visible light. SUMMARY

[0003] In view of the shortcomings of the prior art, the present application provides a kind of multi-state high-level information encryption method based on visible light response time dependence and wavelength selection. The method of the present application uses visible light to drive the color change of the composite system of semiconductor and redox dye, realizes high-level dynamic information encryption and decryption, improves the security level of information storage, and has potential application value in the fields of information security, information storage and anti-counterfeiting.

[0004] The technical scheme of the present application is as follows: A time-dependent and wavelength-selective multi-state advanced information encryption method based on visible light response, comprising the following steps: CdS nanoparticles are dispersed in deionized water, different oxidation-reduction dyes are added, mixed with a high molecular water solution, and then a moisturizing solvent is added, and after uniform mixing, the mixture is quickly poured into a mold to solidify into a film to obtain a photochromic film; The CdS / dye / film with the same initial color system but different dye components is cut into uniform small rods, and is placed on a transparent substrate according to a designed digital password template to prepare a digital password "888"; The digital password is exposed to visible light of different wavelengths for irradiation, and during the irradiation or stop of irradiation, the digital password "888" composed of different dye components undergoes obvious color change, so that the hidden encrypted information can be displayed; According to the present application, preferably, the CdS nanoparticle synthesis method in step (1) comprises the following steps: Cd(NO3)2 is used as a cadmium source, TAA is used as a sulfur source, and ethylene glycol is used as a reducing agent, and the synthesis temperature is 139-140 o C; Further preferably, the molar ratio of Cd(NO3)2 to TAA is 1:1; Further preferably, the molar concentration of Cd(NO3)2 and TAA is 0.5 mmol; Further preferably, the reaction time is 2 min; According to the present application, preferably, the particle size of the CdS nanoparticles in step (1) is 15-20 nm; According to the present application, preferably, the CdS nanoparticles in step (1) are dispersed in deionized water for standby use, and the concentration is preferably 7-10 mg / ml; According to the present application, preferably, the oxidation-reduction dye in step (1) includes methylene blue (MB), methylene green (MG), phenosafranine (PS), neutral red (NR), patent blue (PBV), and basic fuchsin (BF); According to the present application, preferably, the film-forming high molecular matrix in step (1) is agarose; According to the present application, preferably, the moisturizing solvent in step (1) is ethylene glycol or glycerol, and further preferably is ethylene glycol; According to the present application, preferably, the solidification and film formation process in step (1) is under room temperature conditions; According to the present application, preferably, the size of the uniform small rod in step (2) is 3 mm × 10 mm; According to the application, preferably, the transparent substrate in step (2) is common glass or flexible PET, the digital template is placed under the substrate, and the sticks are placed in sequence according to the preset digital password to realize information encryption. According to the application, preferably, the light range with different wavelengths in step (3) is 400-515 nm.

[0005] The principles and advantages of the application are as follows: The information encryption / decryption method of the application is a photochromic film system based on visible light response, excellent visible light response semiconductor CdS nanoparticles are combined with different redox dyes, agarose is selected as a high molecular film forming substrate, and the photochromic film is prepared; under irradiation of visible light with different wavelengths, different redox dyes are reduced to cause discoloration, and display of different encrypted information is realized. In the light irradiation process, different dyes have different oxidation reduction potentials, which leads to different response wavelengths, so that wavelength selective photochromic information display can be realized; and after stopping light irradiation, under the action of oxygen, different oxidation kinetics of the reduced state dyes can further realize time-dependent information display. Therefore, the wavelength selection and time-dependent multi-state advanced information encryption method based on visible light response prepared by the application has the advantages of simple preparation process operation, fast response speed, long cycle life, complex information encryption, high security level, and has potential application value in multi-level dynamic information encryption. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 UV-visible absorption spectrum of CdS nanoparticles; Figure 2 Photo of the discoloration process of the time-dependent photochromic film based on visible light response in Example 1; Figure 3 Schematic diagram of the process of the wavelength selective multi-state advanced information encryption / decryption method based on visible light response in Example 2; Figure 4 Spectrum (a, b) and photo (c) of the discoloration process of the wavelength selective photochromic film based on visible light response in Example 2; Figure 5 Schematic diagram of the process of the wavelength selective multi-state advanced information encryption / decryption method based on visible light response in Example 2; Figure 6 Display effect diagram of the erasable rewritable medium based on visible light response in Example 3 (a) CdS / MB / agarose discoloration film; (b) CdS / PS / agarose discoloration film; (c) CdS / NR / agarose discoloration film; (d) CdS / MG / agarose discoloration film. DETAILED DESCRIPTION

[0007] The application is further described below in connection with specific embodiments, but not limited to the following; meanwhile, the experimental methods described in the following examples are all conventional methods, unless otherwise specified; the reagents and materials described are all commercially available, unless otherwise specified.

[0008] Example 1 A time-dependent multi-state advanced information encryption / decryption method based on visible light response, comprising the following steps: (1) The preparation method of CdS nanoparticles is as follows: 0.4 g TAA and 1.2 g Cd(NO3)2 are respectively dissolved in 4 ml EG, then 9.8 ml EG is heated to 139 o C for 3-4 min, then 380 ul TAA solution (0.5 mmol) is quickly injected into the EG solution, and then 500 ul Cd(NO3)2 solution (0.5 mmol) is injected into the solution, and the reaction is continued at 139 o C for 2 min, after the reaction is completed, the glass bottle is cooled in water bath, centrifuged, and then dispersed in 2.5 ml deionized water for standby. The color of the CdS nanoparticles is yellow, and its ultraviolet-visible absorption spectrum is as follows: Figure 1 (2) Preparation of agarose solution: take 0.2 g agarose, add 6 ml H2O, stir until uniform, and heat the solution to 110 o C until the agarose is completely dissolved; (3) The preparation method of CdS / dye / agarose film is as follows: CdS / MB / agarose film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul EG, then add 15 ul MB (0.01 M), and then quickly add 1 ml of the above agarose solution, quickly shake until uniform, pour into a culture dish with a diameter of 6 cm, and form a film for standby; CdS / basic MB / agarose film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul EG, then add 15 ul basic MB (0.01 M), and then quickly add 1 ml of the above agarose solution, quickly shake until uniform, pour into a culture dish with a diameter of 6 cm, and form a film for standby; CdS / MG / agarose film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul EG, then add 40 ul MG (0.01 M), and then quickly add 1 ml of the above agarose solution, quickly shake until uniform, pour into a culture dish with a diameter of 6 cm, and form a film for standby; ​The three photochromic films can all change from green to yellow after irradiation of 490 nm light. The difference is that the CdS / alkali MB / agarose film reduced first restores to the initial green color because the oxidation kinetics of alkali MB in air is the fastest, and then the CdS / MB / agarose film in the reduced state also restores to the initial green color, and the CdS / MG / agarose film slowly restores to green color at last because of the slow oxidation of MG Figure 2 The photochromic films are cut into small rods (2 mm x 10 mm) for standby; (4) Based on this, the following time-dependent multi-state advanced information encryption / decryption method based on visible light response is prepared: A glass or flexible transparent substrate of 10 cm x 5 cm is taken, and the glass substrate is ultrasonically washed with deionized water, acetone, ethanol and deionized water for 15 minutes in turn and dried for standby; a pre-designed digital password template "888" is placed under the transparent substrate. First, the small rods of CdS / alkali MB / agarose film are placed according to the digital password "117", then the small rods of CdS / MB / agarose film are used to fill the remaining positions of the password "117" according to the password "UJN", and finally, the small rods of CdS / MG / agarose film are used to fill all the remaining positions of the password "888", so that the encrypted information "888" with the initial green color is obtained; (5) When the green password "888" is irradiated with a 490 nm lamp, a yellow password "888" is displayed after 10 s. The yellow password "888" is placed in air, and the small rods containing alkali MB restore to the green password "117" in about 1 min, and then the small rods containing MB also restore to green, and the green password "UJN" is displayed in about 4 min. The small rods containing MG also gradually restore to green in 50 min, and the initial green password "888" is displayed. Only the correct time can obtain the correct password, such as the password "UJN" obtained at 4 min. The initial green password "888" can be used to encrypt and decrypt information again Figure 3 ).

[0009] Example 2 A wavelength-selective multi-state advanced information encryption / decryption method based on visible light response is prepared as described in Example 1, except that: Step (3) is: CdS / MB / PS / agarose film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul of EG, then add 20 ul of MB (0.01 M) and 40 ul of PS (0.01 M), then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a culture dish with a diameter of 6 cm, and form a film for standby; CdS / MB / BF / agarose film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul of EG, then add 20 ul of MB (0.01 M) and 10 ul of BF (0.01 M), then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a culture dish with a diameter of 6 cm, and form a film for standby; wherein BF is a complementary color of PS, which cannot be driven to change color by CdS nanoparticles; CdS / BF / PBV / agarose film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul of EG, then add 10 ul of BF (0.01 M) and 10 ul of PBV (0.01 M), then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a culture dish with a diameter of 6 cm, and form a film for standby; wherein PBV is a complementary color of MB, which cannot be driven to change color by CdS nanoparticles; The above three photochromic films, wherein the CdS / MB / PS / agarose film, after irradiation with 490 nm light, changes from brown to orange due to the reduction of MB to colorless, and then changes from orange to yellow (490 nm light irradiation) due to the reduction of PS to colorless. Figure 4 The CdS / MB / BF / agarose film changes from brown to orange after irradiation with 490 nm light, and remains orange after irradiation with 450 nm light, because MB is reduced to colorless and BF does not change color, and 450 nm light cannot drive BF to change color. The last CdS / BF / PBV / agarose film always shows brown whether irradiated with 490 nm light or 450 nm light. Cut the above photochromic films into small rods (2 mm x 10 mm) with uniform size for standby; Step (4) is: Based on this, the following wavelength-selective multi-state advanced information encryption / decryption method based on visible light response is prepared: Take a piece of 10 cm × 5 cm glass or flexible transparent substrate, wherein the glass substrate is sequentially washed with deionized water, acetone, ethanol and deionized water for 15 minutes, and dried for standby; The pre-designed digital password template "888" is placed under the transparent substrate. First, place the small rod of CdS / MB / PS / agarose film according to the digital password "326", then based on this, place the small rod of CdS / MB / BF / agarose film according to the password "988" to fill the remaining positions of the password "326", and finally, place the small rod of CdS / BF / PBV / agarose film to fill the remaining positions of the password "888", so as to obtain the initial color brown encrypted information "888"; (5) When the brown password "888" is irradiated with a 490 nm lamp, after 10 s, all the small rods containing MB show orange color because MB is reduced to colorless, and an orange password "988" is displayed. Then, it is placed under a 450 nm lamp for irradiation for 40 s, and PS is reduced to colorless, so that the small rods containing PS are all discolored. At this time, a yellow password "326" is obtained, and BF and PBV cannot be reduced and discolored as the complementary colors of PS and MB, respectively. After the yellow password is placed in the air for 8 min, the password can be restored to the initial brown password "888", and the encryption and decryption of information can be realized again. Figure 5 ).

[0010] Example 3 A kind of based on visible light response's erasable rewrite medium, the erasable rewrite medium is prepared using the photochromic material in example 1, and the specific preparation method is as follows: CdS / MB / agarose discoloration film: take 900 ul of the above CdS nanoparticle dispersion liquid, add 900 ul of EG, then add 15 ul of MB (0.01 M), then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a 6 cm diameter culture dish, form a film, and cut it into a 4 cm × 3 cm size erasable rewrite medium for standby; CdS / PS / agarose discoloration film: take 900 ul of the above CdS nanoparticle dispersion liquid, add 900 ul of EG, then add 40 ul of PS (0.01 M), then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a 6 cm diameter culture dish, form a film, and cut it into a 4 cm × 3 cm size erasable rewrite medium for standby; CdS / NR / agarose film color-changing film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul of EG, then add 40 ul of NR (0.01 M), then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a culture dish with a diameter of 6 cm, form a film, and after treating with acid steam for 5-7 s, cut it into 4 cm x 3 cm size erasable rewrite medium for standby; CdS / MG / agarose color-changing film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul of EG, then add 40 ul of MG (0.01 M), then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a culture dish with a diameter of 6 cm, form a film, and after treating with acid steam for 5-7 s, cut it into 4 cm x 3 cm size erasable rewrite medium for standby; Use different light masks to block, irradiate the CdS / MB / agarose color-changing film and the CdS / MG / agarose color-changing film with 490 nm light, respectively, to obtain very clear effect diagrams as shown in Figure 6 a, 6d; Use different light masks to block, irradiate the CdS / PS / agarose color-changing film and the CdS / NR / agarose color-changing film with 450 nm light, respectively, to obtain very clear effect diagrams as shown in Figure 6 b, 6c.

Claims

1. A high-level information encryption method based on visible light response time dependence and wavelength selection, comprising the following steps: (1) Cut different CdS / dye / agarose photochromic films into small rods of uniform size, and paste them on ordinary glass or flexible transparent substrate according to the pre-set numerical password to realize information encryption; (2) Use light of different wavelengths to irradiate, and in the process of fading or recovery, respectively realize the wavelength selection and time-dependent high-level information encryption method.

2. The information encryption / decryption method according to claim 1, characterized by, The CdS / dye / agarose photochromic film in step (1) uses dyes including methylene blue (MB), methylene green (MG), phenosafranine (PS), neutral red (NR), and patent blue (PBV) and basic fuchsin (BF) as complementary colors which cannot be reduced; The information encryption / decryption method according to claim 1, wherein The number of digits to be encrypted in step (1) is not less than 1, preferably 3; The information encryption / decryption method according to claim 1, wherein The CdS nanoparticles in step (1) are prepared by dissolving 0.4 g TAA and 1.2 g Cd(NO3)2 in 4 ml EG respectively, then heating 9.8 ml EG to 139 o C in a glass bottle for 3-4 min, then quickly injecting 380 ul TAA solution (0.5 mmol) into the EG solution, and then injecting 500 ul Cd(NO3)2 solution (0.5 mmol) into the solution, and reacting at 139 o C for 2 min. After the reaction, the glass bottle is cooled in water bath, centrifuged, and then dispersed in 2.5 ml deionized water for standby. The information encryption / decryption method according to claim 1, wherein the preparation method of the agarose in step (1) is: taking 0.2 g of agarose, adding 6 ml of H2O, stirring uniformly, heating the solution to 110 o C until the agarose is completely dissolved. The information encryption / decryption method according to claim 1, wherein The preparation method of the CdS / dye / agarose photochromic film in step (1) is as follows: (1) CdS / MB / agarose film: take 900 ul of the above CdS nanoparticle dispersion, add 900 ul of EG, then add 15 ul of MB (0.01 M), and then quickly add 1 ml of the above agarose solution, shake quickly and uniformly, pour into a culture dish with a diameter of 6 cm, and reserve for use; (2) CdS / basic MB / agarose film: same as (1), except that 15 ul of basic MB (0.01 M) is added; (3) CdS / MG / agarose film: same as (1), except that 40 ul of MG (0.01 M) is added; (4) CdS / MB / PS / agarose film: same as (1), except that 20 ul of MB (0.01 M) and 40 ul of PS (0.01 M) are added; (5) CdS / MB / BF / agarose film: same as (1), except that 20 ul of MB (0.01 M) and 10 ul of BF (0.01 M) are added; wherein BF is a complementary color of PS, which cannot be driven to change color by CdS nanoparticles; (6) CdS / BF / PBV / agarose film: same as (1), except that 10 ul of BF (0.01 M) and 10 ul of PBV (0.01 M) are added; wherein PBV is a complementary color of MB, which cannot be driven to change color by CdS nanoparticles; The information encryption / decryption method according to claim 1, wherein The CdS / dye / agarose photochromic film in step (1) is cut into small rods (2 mm × 10 mm); The method for time-dependent information encryption / decryption according to claim 1, characterized in that, Select dyes MB and MG in claim 2, treat MB with ammonia water, and prepare three dyes into CdS / MB / agarose photochromic film, CdS / basic MB / agarose photochromic film, and CdS / MG / agarose photochromic film, and cut them into small rods; The method for wavelength-selected information encryption / decryption according to claim 1, characterized in that, The dyes MB, PS, PBV and BF in claim 2 are selected, and MB and PS, MB and BF, and PBV and BF are mixed respectively to prepare CdS / MB / PS / agarose photochromic film, CdS / MB / BF agarose photochromic film and CdS / PBV / BF agarose photochromic film, which are cut into small rods. The information encryption / decryption method according to claim 1, wherein The different wavelengths of light in step (2) are 400-515 nm, preferably 450 nm and 490 nm.

Images