## 4 Implementation of the Proposed Method
The first element in the upper triangular, square HPD matrix has the value 339. Based on that value, we first look for the byte position in the B channel. After that, we change its LSB with the first bit of the binary representation of the secret message. Following that rule, based on the absolute values of the upper triangular square HPD matrix, 339, 87, 110, etc., characters are selected in the Blue channel of carrier data, and the Least Significant Bit (LSB) of those characters are replaced by bits of the encrypted message, 0, 1, 0, etc., respectively. Let us look at the hidden message whose binary notation is 0100011101000101010100. At position 339 in the B channel of a carrier, the data contain character m, whose binary value is 01101101. The last digit is 1, and the first binary digit in the hidden message is 0. It is necessary to make a change and, therefore, it is necessary to transform the character m into the character 1 01101100. The situation is similar to the other characters, so we have the following. The next position in the upper triangular square HPD matrix is \(1-871\to\) so, character s \(\to\) binary value 01110011 \(\to\) the least significant bit (LSB) of this character and the next bit in the hidden message 1, are equal, and then there are no changes, the character remains the same s. The next position is 110 \(\to\) so, character d \(\to\) binary value 01101110 \(\to\) the least significant bit (LSB) of this character is 0, there are no changes, and the character remains the same d. After replacing all 24 bits of hidden message, is obtained a binary record in the following form (see Figure 6). Now, it is necessary to transform the binary record into a base64 record, as in the following image (see Figure 7). Figure 6: Binary of the B channel with an embedded secret message. Figure 8: B channel with an embedded secret message. What remains is to merge all three channels, R, G, and B, into a single image (see Figure 9). Figure 9: Original image with an embedded secret message. Selection  
The selection phase is where the unique values of a Hermitian positive definite matrix come into play. This type of matrix has special properties: it is symmetric and has all positive eigenvalues, which makes it suitable for various applications in linear algebra and signal processing. In this context, the matrix is utilized to determine the specific bits to extract from the binary data generated in the previous phase. By applying a selection algorithm that leverages the characteristics of the Hermitian matrix, the module identifies the bits that will potentially hold parts of the hidden message. This selection process is designed to maximize the robustness of the data extraction while minimizing the risk of altering the original image data. Modification  
The modification phase involves the actual extraction of bits from the stego-object based on the positions indicated by the upper triangular elements of the Hermitian positive definite matrix. This matrix is instrumental in defining a set of indices that pinpoint where the relevant bits reside within the binary data. As the bits are extracted, they are carefully modified to create a coherent stream of information that corresponds to the hidden message. This step is crucial because it ensures that the extraction process does not disturb the visual integrity of the carrier image. The resulting output at this stage is a binary representation of the hidden message, preserved from potential corruption or loss during extraction. Secret Message Generation  
The final phase of the process is the culmination of the previous steps, resulting in the creation of the secret message. In this phase, the binary data extracted in the modification step is translated back into a human-readable format. This may involve decoding the binary sequence back into its original text or data format, depending on how the message was originally embedded. This transformation completes the data extraction process, delivering the hidden message to the user.