When using Privateencrypt for encryption, publicdecrypt after the decryption end, the encryption before the string and decrypted string, if compared, is not the same, use your example is the same. I turned two strings into byte arrays and found that the decrypted byte array was preceded by an extra element of 0.
testData:="abcdefg"
encryption before the string into byte arrays:
[97 98 99 100 101 102 103]
decrypted string bytes
[0 97 98 99 100 101 102 103]