Thank you so much for your information. I installed the pgCrypto. Now I have more than 40 functions (i believe all are from pgcrypto) but when I try to run your query:
I am very concerned about security in my application becouse we are going to moviment a large ammount of information and money. As much i take care of it as good.
SHA1 and MD5 are hashing algorithms, they are typically used for passwords and in conjunction with public key encryption or over-the-wire encryption to sign the message. If you are really concerned about security, you may want to hire an experienced person in the security engineering field. Especially if you are talking about financial information.
I know some problem of MD5 and know it is very good too. If someone could tell me where MD5 is used I could be more relaxed.
The impression I get is that SHA-256, SHA-384, or SHA-512 are the preferred hashing algorithms, but I really don't keep up on it. Many many password systems use MD5, I think it is reasonably safe.